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NB/T 47013.3-2015

Chinese Standard: 'NB/T 47013.3-2015'
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Detail Information of NB/T 47013.3-2015; NB/T47013.3-2015
Description (Translated English): (Nondestructive testing of pressure equipments - Part 3: Ultrasonic testing)
Sector / Industry: Energy Industry Standard (Recommended)
Classification of Chinese Standard: H26
Date of Issue: 2015-04-02
Date of Implementation: 2015-09-01
Older Standard (superseded by this standard): JB/T 4730.3-2005
Regulation (derived from): ?Energy Bureau Announcement 2015 No. 3

NB/T 47013.3-2015
ENERGY INDUSTRY STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
ICS 77.040.20
H 26
Replacing JB/T 4730.3-2005
Nondestructive testing of pressure equipment
- Part 3: Ultrasonic testing
承压设备无损检测
第 3部分: 超声检测
[Including Modification 2018XG1]
ISSUED ON: APRIL 02, 2015
IMPLEMENTED ON: SEPTEMBER 01, 2015
Issued by: National Energy Administration
Table of Contents
Foreword ... 5
1 Scope ... 9
2 Normative references ... 9
3 Terms and definitions ... 10
4 General requirements ... 11
5 Ultrasonic testing methods and quality grading for standby raw material or
components of pressure equipment ... 18
6 Ultrasonic testing method and quality grading of welded joint for pressure
equipment ... 49
7 Ultrasonic measuring methods for thickness of pressure equipment ... 77
8 Ultrasonic testing methods of in-service pressure equipment ... 84
9 Ultrasonic testing records and reports ... 96
Annex A (Normative) Requirements for electrical performance indicators of
ultrasonic testing instruments ... 98
Annex B (Normative) Requirements for performance indicators of probe used
for ultrasonic testing ... 102
Annex C (Normative) Requirements for performance of double-crystal straight
probe ... 104
Annex D (Normative) Ultrasonic testing methods and acceptance standard for
plates used for pressure equipment by using an angle probe... 106
Annex E (Normative) Ultrasonic testing methods (by using an angle probe) and
quality classification of steel forgings used for pressure equipment ... 109
Annex F (Normative) Ultrasonic testing methods (by using an angle probe) for
austenitic steel forgings used for pressure equipment ... 112
Annex G (Normative) Ultrasonic testing method and quality classification of the
welding overlay of pressure equipment ... 114
Annex H (Normative) Ultrasonic testing method and quality classification of the
butt joints of pressure equipment made by aluminum & aluminum alloy and
titanium ... 119
Annex I (Informative) Ultrasonic testing method and quality classification of the
butt joints of austenitic stainless steel ... 123
Annex J (Normative) Ultrasonic testing method of the curved longitudinal butt
joints of pressure equipment ... 132
Annex K (Normative) Ultrasonic testing method of the curved circumferential
butt joints of pressure equipment ... 136
Annex L (Normative) Ultrasonic testing method of fillet joints for nozzles and
shells (or heads) of pressure equipment ... 139
Annex M (Normative) Ultrasonic testing method of T-type welding joints ... 145
Annex N (Normative) Specific requirements for the ultrasonic testing for welding
joints of different types ... 148
Annex O (Normative) CSK-III A Test specimen ... 160
Annex P (Normative) Determination of the loss difference during sound energy
transmission ... 161
Annex Q (Normative) Echo dynamic patterns ... 165
Annex R (Normative) Defect Height Measurement Method (I) Measure defect
height by the endpoint wave diffraction method ... 169
Annex S (Normative) Defect Height Measurement Method (II) The End Echoes
Diffraction Method to Measure the Defect Height ... 176
Annex T (Normative) Defect Height Measurement Method (III) Using -6 dB
method for measuring defect heights ... 179
Modification Notification of Industry Standard NB/T 47013.3-2015 (2018XG1)
... 182
Foreword
This Standard, NB/T 47013 “Nondestructive testing of pressure equipment”, consists
of the following 13 parts:
- Part 1: General requirements;
- Part 2: Radiographic testing;
- Part 3: Ultrasonic testing;
- Part 4: Magnetic particle testing;
- Part 5: Penetrant testing;
- Part 6: Eddy current testing;
- Part 7: Visual testing;
- Part 8: Leak testing;
- Part 9: Acoustic emission testing;
- Part 10: Ultrasonic time of flight diffraction technique testing;
- Part 11: X-ray digital radioscopic examination;
- Part 12: Magnetic flux leakage testing;
- Part 13: Pulsed eddy current testing.
This Part is Part 3: Ultrasonic testing of NB/T 47013.
This Part is drafted according to the rules provided in GB/T 1.1-2009 “Directives for
standardization - Part 1: Structure and drafting of standards”.
This Part replaces JB/T 4730.3-2005 “Nondestructive testing of pressure equipment -
Part 3: Ultrasonic testing”. The main technical changes are as follows, compared with
JB/T 4730.3-2005:
- ADD “terms and definitions”, including terms and definitions related to ultrasonic
testing in the former JB/T 4730.1;
- REPLACE JB/T 10061 “Shape A Pulse Reflection Ultrasonic Flaw Detector -
General Technology Condition” WITH GB/T 27664.1 “Nondestructive Testing
Performance and Inspection of Ultrasonic Testing Equipment - Part 1: Instrument”.
Put forward more scientific requirements for performance of ultrasonic testing
equipment;
- ADD specific performance indicator requirements for ultrasonic test instrument
and probe;
- ADD requirements for calibration, inspection, operational inspection; and check of
ultrasonic test instrument and probe;
- ADD “safety requirements”; and put forward requirements for safety of personnel
in process of ultrasonic test;
- ADD requirements for process files; and list out the related factors to formulate
process procedure;
- RE-DIVIDE types (standard test block and reference block) of test blocks used in
this part; and such division was implemented mainly based on domestic general
standards, instead of dividing types of standard test block and reference block in
this Part;
- ADJUST the sequence of “ultrasonic testing methods and quality grading for
standby raw material or components of pressure equipment”, so as to formulate
in accordance with the order of plate, composite plate, carbon steel and low alloy
steel forgings, steel bolt billet, austenite steel forgings, seamless steel pipe and
so on;
- COMBINE ultrasonic testing methods and quality grading of carbon steel and low
alloy steel, aluminum and aluminum alloy plate, titanium and titanium alloy plate,
as well as nickel and nickel alloy plate, austenite stainless steel and duplex
stainless steel, and so on. Redesign reference blocks. The detection sensitivity
shall be mainly determined by flat bottom hole distance amplitude curves of
reference blocks. Modify the quality grade requirements to stricter requirements
for qualified indicators at all levels. As the plates in JB/T 4730.3-2005 have lower
requirements for testing quality level, it is difficult to control the quality
requirements, and moreover, as it has larger difference from specific indicators as
required by ISO, EU EN and other related quality requirements, therefore, it
modifies the quality grading in accordance with EU EN and other standards;
- INTEGRATE the contents in two chapters of 2005-version, “ultrasonic detection
and quality grading for butt joint of pressure equipment" and "ultrasonic detection
and quality grading for pipe and pressure pipe ring of pressure equipment”.
Classification shall be conducted according to the type of welded joint, base
material nominal thickness and the size of detecting surface curve rate;
- Applicable scope of welded joint base material nominal thickness of pressure
equipment is expanded from 8 mm ~ 400 mm to 6 mm ~ 500 mm;
- REDESIGN the position and the number of the artificial reflector on CSK-IIA and
CSK - IVA blocks. In this way, it not only guarantees the coverage of the detection
area coverage, but also is suitable for adjustment of the straight probe benchmark
sensitivity. New CSK-IIA block is applicable for work piece with thickness scope of
6 mm ~ 200 mm, mainly referring to the European Union (EN) and Japanese
standard (JIS). New CSK-IVA block is applicable for work piece with thickness
scope greater than 200 mm ~ 500 mm, and makes improvement on basis of mainly
referring to the ASME codes. The block diameter of artificial reflector shall be 6
mm;
- REFINE the weld ultrasonic testing requirements for different types. It involves flat
butt joint, T-shaped welded joint, plug-in Angle joint, L-shaped welded joint,
placement type pipe and cylinder (or seal-end socket) angle joint, cross welding
joint, embedded type pipe and cylinder (or end socket) butt joint etc.
- REDESIGN the GS test block. Increase the circular arc surfaces etc. It is mainly
beneficial to adjusting time base of arc probe;
- LIMIT the length of non-crack defect in Zone I in quality grade of weld joint;
- ADJUST overall formulation structure involved in weld joint ultrasonic testing. The
ultrasonic testing method of connecting pipe and cylinder (head) angle joint,
ultrasonic testing method of T-shaped weld joint, ultrasonic testing method and
quality grading of surfacing welding layer are included into the annex;
- ADD “ultrasonic thickness measurement method for the pressure equipment” in
accordance with actual testing requirements, including measurement method for
stainless steel surfacing layer thickness;
- When pressure equipment is used to conduct ultrasonic detection, ADD failure
mode of host materials, components or welded joint which may be caused in use
process or analysis results of risk evaluation to select ultrasonic testing method,
detection parts and detection proportion.
This Part is proposed by and shall be under the jurisdiction of National Technical
Committee on Boiler Pressure Vessel of the Standardization Administration of China
(SAC/TC 262).
Drafting organizations of this Part: Hefei General Machinery Research Institute, China
Special Equipment Inspection Institute, Shanghai Electric and Nuclear Power
Equipment Co., Ltd., China First Heavy Machinery Group Dalian Hydrogenation
Reactor Manufacturing Co., Ltd., Jiangsu Special Equipment Safety Supervision and
Inspection Research Institute, and Lanzhou Lanshi Heavy Equipment Co., Ltd.
Main drafters of this Part: Yan Changzhou, Zheng Hui, Xu Zunyan, Zhou Fengge, Zhou
Yufeng, Tao Yuanhong, Zheng Kai, Gu Jie, Zhang Baozhong and Pan Qianghua.
The historical version of the standards replaced by this Part are as follows:
- JB 4730-1994, JB/T 4730.3-2005.
Nondestructive testing of the pressure equipment -
Part 3: Ultrasonic testing
1 Scope
1.1 This Part of NB/T 47013 specifies the pressure equipment shall adopt ultrasonic
testing method and quality grading requirements in which shape A pulse reflection
ultrasonic detector is used to test work piece defect.
1.2 This Part is applicable to ultrasonic detection for metal material system pressure
equipment with raw materials or components and welded joint, and be applied to
ultrasonic detection of metal materials used in the pressure equipment.
1.3 This Part specifies ultrasonic measuring method for thickness of the pressure
equipment.
1.4 Ultrasonic detection of supporting parts and structural piece related to the pressure
equipment can also refer to this part.
2 Normative references
The following documents are necessary to the application of this document. For all
dated references, only the dated edition applies to this document. for all undated
references, the latest edition (including all amendments) applies.
GB/T 11259 Non-destructive testing - Practice for fabrication and control of steel
reference blocks used in ultrasonic testing
GB/T 12604.1 Non-destructive testing - Terminology - Terms used in ultrasonic
testing
GB/T 27664.1 Non-destructive testing - Characterization and verification of
ultrasonic test equipment - Part 1: Instruments
GB/T 27664.2 Non-destructive testing - Characterization and verification of
ultrasonic test equipment - Part 2: Probes
JB/T 8428 Non-destructive testing - Blocks for ultrasonic testing
JB/T 9214 Non-destructive testing - Practice for evaluating performance
characteristics of A scope ultrasonic pulse - Echo testing systems
JB/T 10062 Testing methods for performance of probes used in ultrasonic flaw
detection
NB/T 47013.1 Nondestructive testing of pressure equipment
3 Terms and definitions
The following terms and definitions in GB/T 12604.1 and NB/T 47013.1 are applicable
to this Part.
3.1
Reduction of backwall echo caused by the presence of discontinuities BG/BF
In time of forging test, ratio of the initial backwall echo BG in the intact area close to
defect place and the initial backwall echo BF within the defect place, expressed as dB
value.
3.2
Grouped discontinuities
In time of forging test, there are five or more defect reflection signals within 50 mm
acoustic distance at the same time on the display screening line, or five or more defect
reflection signals within the same depth scope were found on the inspection surface
of 50 mm × 50 mm, and the reflection amplitude are greater than or equal to defect of
an equivalent flat bottom hole diameter.
3.3
Reference sensitivity
It refers to sensitivity when height of reference block artificial reflection echo or height
of inspected work piece bottom are adjusted to a certain reference.
3.4
Scanning sensitivity
Based on reference sensitivity, dB value (increment) shall be properly improved in
accordance with surface condition, testing defect requirements and probe types to
conduct sensitivity of actual detection.
3.5
Through thickness dimension of the flaw
The size of defect on the direction of base material nominal thickness.
3.6
Echodynamic patterns
Envelope curve of probe moving distance and the corresponding defect reflector echo
envelope changes.
3.7
Base material nominal thickness
Base material nominal thickness is defined as follows:
a) For plate butt joint, when the thickness of the parent materials at both sides of
the weld is equal, the base material nominal thickness t is the nominal thickness
of the parent materials at thinner side;
b) For plug-in connecting pipe Angle joint, base material nominal thickness t is the
nominal thickness of cylinder or end socket; placement connecting pipe and
cylinder (or end socket) Angle joint, the base material nominal thickness t is
nominal thickness of connecting pipe;
c) For T-shaped weld joint, the base material nominal thickness t is nominal
thickness of plate.
4 General requirements
4.1 Inspector
4.1.1 The general requirements for ultrasonic testing personnel shall be in conformity
with the relevant provisions in NB/T 47013.1.
4.1.2 Ultrasonic testing personnel shall master basic knowledge about certain metal
materials, equipment manufacturing and installation, welding and heat treatment etc.,
shall be familiar with material, geometry size and acoustic properties of the tested work
piece etc., and shall make analysis, judgment and processing to problems found in
inspection.
4.2 Testing equipment and instrument
4.2.1 Product quality qualification certificate of instrument and probe
It shall at least give out preheating time, low voltage alarm or automatic shutdown
voltage with low voltage, pulse repetition frequency, effective output impedance, firing
pulse voltage, pulse rise time and firing pulse width (using square wave pulse impact
as firing pulse), receiving circuit band and other main performance parameters in
product quality certification of ultrasonic testing instrument the probe shall provide
center frequency, bandwidth, impedance or static capacitance, relative pulse echo
sensitivity and Angle probe beam performance (including probe frontier distance (shot
point), Value K (refraction Angle β) and other major parameters.
4.2.2 Test instrument, probe and combined performance
4.2.2.1 Testing instruments
Use A type pulse reflection ultrasonic detector, and the working frequency shall include
at least frequency range of 0.5 MHz ~ 10 MHz based on -3 dB measurement, test
conditions and parameters of each performance in the ultrasonic instrument shall meet
the requirements of annex A and provide certification documents. The test method
shall be based on provisions in GB/T 27664.1.
4.2.2.2 Probe
Circular wafer shall not be greater than 40 mm in diameter, and either side length of
square chip shall not be more than 40 mm in general. The performance indicators shall
meet the requirements of annex B and provide certification documents. The test
method shall be based on provisions in GB/T 27664.2.
4.2.2.3 Combined performance of instrument and probe
4.2.2.3.1 Combined performance of instrument and probe includes horizontal linear,
vertical linear, combined frequency, margin sensitivity, blind area (only limited to
straight probe) and far field resolution.
4.2.2.3.2 It shall measure combined performance of instrument and probe in the
following cases:
a) Newly purchased ultrasonic testing instrument and (or) probe;
b) After instrument and probe are repaired or have major components replaced;
c) When inspectors doubted.
4.2.2.3.3 The horizontal linear deviation is not more than 1 %, and vertical linear
deviation is not more than 5 %.
4.2.2.3.4 The deviation between combined frequency of instrument and probe and
nominal frequency of probe shall not be more than plus or minus 10 %.
4.2.2.3.5 Combined performance of instrument and straight probe shall meet the
following requirements:
a) Sensitivity allowance shall not be less than 32 dB;
b) Under reference sensitivity, for probe with nominal frequency of 5 MHz, the blind
area is not more than 10 mm; for probe with the nominal frequency of 2.5 MHz,
the blind area is not more than 15 mm;
c) The far field resolution of straight probe is not less than 20 dB.
4.2.2.3.6 Combined performance of instrument and angle probe shall meet the
following requirements:
a) Sensitivity allowance shall not be less than 42 dB;
b) The far field resolution of angle probe is not less than 12 dB.
4.2.2.3.7 When it reached the maximum detection acoustic distance of the detected
work piece, the effective sensitivity allowance shall be not less than 10 dB.
4.2.2.3.8 The testing method for combined frequency of instrument and probe shall be
based on provisions in JB/T 10062, and testing method for other combined
performance shall refer to provisions in JB/T 9214.
4.2.3 Test block
4.2.3.1 Reference block
4.2.3.1.1 Reference block is a material block with specified chemical composition,
surface roughness, heat treatment and geometry, used for evaluating and calibrating
ultrasonic testing equipment, which is test block used for calibrating instrument probe
system performance. Reference block used by this part is No. 20 high-quality carbon
structural steel CSK-IA, DZ-I and DB-P Z20-2.
4.2.3.1.2 See this part for specific shape and size of CSK - IA test block, and see JB/T
9214 for specific shape and size of DZ-O and DB-P Z20-2.
4.2.3.1.3 The manufacture of reference test block shall meet the requirements of JB/T
8428; the manufacturer shall provide product quality certificate and ensure that the
maximum reflection amplitude difference shall be less than or equal to 2 dB when each
reference test block manufactured is compared to national standard sample or similar
reference test block with quantity transmission under same test condition.
4.2.3.2 Reference block
4.2.3.2.1 Reference block refers to test block with similar chemical composition as
inspected work piece or material and including reference reflector with clear meaning
(reflector shall be made by machining way), to regulate amplitude and acoustic
distance of the ultrasonic testing equipment, so as to compare tested defect signal with
signals produced by the known reflector, namely test block used for inspection.
4.2.3.2.2 Overall dimensions of reference block shall be able to represent features of
inspected work piece, and thickness of test block shall be corresponding to thickness
of inspected work piece. If it involved inspection of butt joint with different thickness,
the selection of the test block thickness shall be determined by thickness of the larger
one.
4.2.3.2.3 The reference block shall be made by materials with same or similar acoustic
performance as the inspected materials. When straight probe is used for detection, it
is not allowed having defects with flat bottom quantity diameter greater than or equal
to Φ2 mm.
4.2.3.2.4 The shape, size and quantity of reference block artificial reflector used for
different inspected work piece ultrasonic inspection shall comply with the provisions in
relevant sections of this Part.
4.2.3.2.5 When it clearly requires size accuracy of reference block in this part, it shall
provide related evidence document, and it shall refer to provisions in JB/T 8428 without
clear requirements.
4.2.4 Coupling agent
4.2.4.1 Sound permeability of coupling agent shall be better and not damage detection
surface detection, such as machine oil, chemical paste, glycerin and water etc.
4.2.4.2 Control on content of coupling agent contaminants
4.2.4.2.1 Adding content of coupling agent shall not be greater than 250 mg/L if used
on nickel-based alloy.
4.2.4.2.2 The total halogen (chlorine and fluorine) of coupling agent shall not be greater
than 250 mg/L if used on austenite stainless steel or titanium.
4.2.5 Calibration, verification, operation review and check requirements for ultrasonic
testing equipment and instrument
4.2.5.1 Calibration, verification and operation review shall be conducted on reference
test block. The main beam of the probe shall vertically align to reflector’s reflective
surface to obtain stable and the largest reflected signal.
4.2.5.2 Calibration or verification
4.2.5.2.1 It shall at least calibrate horizontal linear, vertical linear, combined frequency,
blind area (only limited to straight probe), margin sensitivity and resolution in combined
performance of the ultrasonic instrument and probe as well as attenuator precision of
the instrument once a year, and record. Test is required to meet provisions in 4.2.2.3.
4.2.5.2.2 It shall at least review surface corrosion and mechanical damage of reference
test block and reference block once a year.
4.2.5.3 Operational review
4.2.5.3.1 It shall at least review horizontal linear and vertical linear of analog ultrasonic
detector every 3 months or digital ultrasonic detector every 6 months in combined
performance of the instrument and probe, and record. Test is required to meet
provisions in 4.2.2.3.
4.2.5.3.2 It shall at least review blind area (only limited to straight probe), margin
sensitivity and resolution every 3 months, and record. Test is required to meet
provisions in 4.2.2.3.
4.2.5.4 Inspection
4.2.5.4.1 It shall check whether instrument and equipment appearance, cable
connection and boot signals are normal before each test.
4.2.5.4.2 When angle probe is used, it shall measure incidence point (frontier distance)
and refraction angle (value K) before inspection.
4.2.5.5 Precaution on calibration, operational verification and check
In time of calibration, operational verification and check, the controller to affect the
instrument linear (such as inhibit or filter switch etc.) shall be placed in “off” position or
at the lowest level.
4.3 Test of process file
4.3.1 Test of process file includes process procedures and operating instructions
4.3.2 The process procedure shall also specify specific scope or requirements for
related factors listed in table 1 and relevant chapters and section, in addition to meet
requirements in NB/T 47013.1. When changes in related factors are beyond the rules,
it shall formulate again or revise the process procedures.
4.3.3 The operating instructions shall be formulated based on the content of process
procedure and test requirements of inspected work piece. In addition to meet
requirements in NB/T 47013.1, the content shall also include:
a) Test technology requirements: test technology (straight probe test, angle probe
test, direct contact method, and immersion method etc.) and test wave form etc.;
b) Test object: category of pressure equipment, name, specification and material of
tested object, and heat treatment state, test parts etc.;
c) Test equipment: instrument type, probe specification, coupling agent, test block
type, project, timing and performance indicators of instrument and probe
performance test etc.;
d) Technical parameters related to test process: scanning direction and scanning
range, defect quantitative method, inspection records and evaluation
requirements, and test schematics etc.
Table 1 -- Related factors involved in ultrasonic testing procedure
S/N Content of related factors
1 Work piece shape includes specification and material etc.
2 Requirements for test surface
3 Testing technology (straight probe test, angle probe test, direct contact method, and immersion method etc.)
4 Probe refraction angle and its waveform in the work piece (transverse wave and longitudinal wave); probe nominal frequency, wafer size and wafer shape
5 Testing instrument type
6 Coupling agent type
7 Calibration (test block and calibration method)
8 Scanning direction and scanning scope
9 Scanning mode (manual or automatic)
10 Defect quantitative method
11 Computer data acquisition (when used); automatic alarm and/or recording device (when used)
12 Personnel qualifications; test report requirement
4.3.4 The operating instructions shall be performed with process verification before
initial application. The verification method can be conducted on related reference block.
The verification content includes sensitivity within test scope, signal-to-noise ratio and
whether meet the testing requirements.
4.4 Safety requirements
Test place, environment and safety protection shall comply with provisions in NB/T
47013.1.
4.5 Test implementation
4.5.1 Test preparation
4.5.1.1 When the pressure equipment is manufacturing, installing and testing,
selection of ultrasonic testing time and test rate shall be consistent with the provisions
of the relevant laws and regulations, standards and related technical documents.
4.5.1.2 Confirmed test surface shall ensure that the tested part of work piece can be
fully tested.
4.5.1.3 Surface quality of weld shall be qualified through appearance check. It shall
remove all paint, dirt and rust, splash and contaminants to influence test on test surface
(area passing probe), and its surface roughness shall conform to the requirements of
the test. The irregular state on the surface shall not affect the validity of test results.
4.5.2 Scanning coverage
In order to ensure ultrasonic sound beam can scan the overall tested area of work
piece while testing, every scanning coverage of the probe shall be greater than probe
diameter or 15 % of the width or it shall give priority to satisfy the demands of test
coverage requirements in related chapters.
4.5.3 Movement speed of the probe
Probe scanning speed shall not exceed 150 mm per second commonly. When
automatic alarm device is used for scanning, the scanning speed shall be based on
the reference test to determine.
4.5.4 Scanning sensitivity
Setting of scanning sensitivity shall comply with the provisions in the relevant chapter.
4.5.5 Sensitivity compensation
a) Coupling compensation: in time of testing and defect quantitative, compensation
shall be made to coupling loss caused by difference between reference block
and surface roughness of tested work piece;
b) Attenuation compensation: in time of testing and defect quantitative,
compensation shall be made to sensitivity decline and defect quantitative error
caused by difference between reference block and material attenuation of tested
work piece;
c) Hook face compensation: in time of testing and defect quantitative, for work piece
with hook tested face, compensation shall be made to coupling loss caused by
difference between work piece and radius of reference block curvature.
4.5.6 Review of instrument and probe system
4.5.6.1 Review shall be carried out to the system in the following cases:
a) When there are changes in probe, coupling agent and instrument regulation;
b) When it is suspected that scanning range or scanning sensitivity have changes;
c) It has worked for more than 4 hours continuously;
d) When the work is done.
4.5.6.2 Review of the scanning range
If the offset on the scanning line at any point exceeds 10 % of reading on the scanning
line at this point or 5 % of the full scanning range, it shall readjust scanning range, and
review shall be carried out to all tested positions since last review.
4.5.7 Review of scanning sensitivity
While reviewing, if the scanning sensitivity or distance within tested scope are found
to have artificial reflector echo amplitude dropping 2 dB on wave curves in any depth,
review shall be carried out to all tested positions since last review; if the echo amplitude
rises 2 dB, it shall reevaluate all recording signals.
5 Ultrasonic testing methods and quality grading for
standby raw material or components of pressure
equipment
5.1 Scope
This chapter specifies ultrasonic testing methods and quality grading for standby raw
material or components of pressure equipment.
5.2 Ultrasonic testing process files for standby raw material or components of
pressure equipment
Ultrasonic testing process files for standby raw material or components of pressure
equipment shall also include related factors listed in table 2, in addition to meet
requirements in 4.2.
Table 2 -- Related factors involved in ultrasonic testing process procedure for
raw material or components
S/N Content of related factors
1 Product shape (plate, pipe material, and forgings etc.)
2 Tested time (such as before or after heat treatment)
3 Tested scope
4 Quality acceptance level
5.3 Ultrasonic testing method and quality grading for standby plate of pressure
equipment
5.3.1 Scope
5.3.1 This article is applicable for ultrasonic testing method and quality grading for
standby plate of pressure equipment made of by carbon steel and low alloy steel with
thickness of 6 mm to 250 mm.
5.3.1.2 Ultrasonic testing method shall be conducted according to this article for
aluminum and aluminum alloy plate, titanium and titanium alloy plate, nickel and nickel
alloy plate, copper and copper alloy plate, and quality grading shall also be based on
this article.
5.3.1.3 Ultrasonic testing method shall be conducted according to this article for
austenite stainless steel and austenite, ferritic duplex stainless steel plate, and quality
grading shall also be based on this article.
5.3.2 Testing principle
5.3.2.1 The plate generally uses straight probe for testing.
5.3.2.2 If there is a doubt or when there are provisions in the technical agreement in
the testing process, angle probe can be used for testing.
5.3.2.3 It can choose to conduct testing to any rolling surface of the plate. If inspectors
think it necessary or technical conditions required, it can also choose to conduct testing
respectively to upper and lower rolling surface of plate.
5.3.3 Probe selection
5.3.3.1 Straight probe
5.3. 3.1.1 Selection of straight probe shall be in accordance with the provisions in table
3.
Table 3 -- Straight probe selected for ultrasonic testing of standby plate for
pressure equipment
Plate
thickness/mm Probe used
Nominal
frequency/MHz
Probe wafer
size(recommended)/mm
6 ~ 20 Double wafer straight probe 4 ~ 5 Circular wafer diameter
Φ10 ~ 30
Square wafer side
length 10 ~ 30
> 20 ~ 60 Double wafer straight probe or single wafer straight probe 2 ~ 5
> 60 Single wafer straight probe 2 ~ 5
5.3.3.1.2 When immersion method is used to test plate with thickness less than or
equal to 20 mm, single wafer straight probe can be selected for testing.
5.3.3.1.3 Performance of double wafer straight probe shall meet requirements in Annex
C.
5.3.3.2 Angle probe
The selection of Angle probe shall be in accordance with the provisions in Annex D.
5.3.4 Reference block
5.3.4.1 When double wafer straight probe is used to test plate with thickness less than
20 mm, the ladder flat test block can be adopted as shown in figure 1.
5.3.4.2 When it is used to test plate with thickness greater than 20 mm, the shape and
the size of reference block shall meet provisions in table 4 and figure 2. reference block
artificial reflector is a flat bottom hole with Φ5 mm, and the number of reflector shall be
at least 3.
Figure 1 -- Ladder flat bottom test block
5.3.5 Determination of sensitivity
5.3.5.1 When plate thickness is less than or equal to 20 mm, ladder flat bottom test
block can be used to regulate as shown in figure 1, and it can also use intact part of
tested plate without defect to regulate. At this moment, it can adjust to 50 % of full scale
with first bottom wave of test block or tested plate whose thickness is equal to the work
piece, and then lift to 10 dB as standard sensitivity.
5.3.5.2 When plate thickness is greater than 20 mm, probe and instrument shall be
used to draw a distance - wave curve on the plat bottom hole test block of Φ5 mm,
and such curve can be taken as standard sensitivity.
All
5.3.5.3 If it can determine the relation between the plate bottom echo and Φ5 mm of
flat bottom hole with different depth, it can adopt intact part without defect to regulate
standard sensitivity for the first bottom wave.
5.3.5.4 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
Table 4 -- Reference block used for standard plate ultrasonic testing of
pressure equipment
Unit: mm
SN of test
block
Plate
thickness t
Distance from tested surface to
flat bottom hole S
Thickness of test
block T
Width of test block
1 > 20 ~ 40 10, 20, 30 40 30
2 > 40 ~ 60 15, 30, 45 60 40
3 > 60 ~ 100 15, 30, 45, 60, 80 100 40
4 > 100 ~ 150 15, 30, 45, 60, 80, 110, 140 150 60
5 > 150 ~ 200 15, 30, 45, 60, 80, 110, 140, 180 200 60
6 > 200 ~ 250 15, 30, 45, 60, 80, 110, 140, 180, 230 250 60
Note 1: when plate thickness is greater than 40 mm, the thick test block can be replaced by
thinner one.
Note 2: In order to decrease size and weight of a single test block, flat bottom hole with same
or similar acoustic performance on the test block can be processed to test block with different
thickness.
Figure 2 -- Schematic chart for reference block for plate ultrasonic testing
5.3.6 Testing
5.3.6.1 Coupling method
All
Coupling method can use direct contact method or immersion method.
5.3.6.2 Sensitivity compensation
In time of testing, coupling compensation and attenuation compensation shall be
carried out according to the actual situation.
5.3.6.3 Scanning way
a) It shall perform 100 % scanning on the edge of the plate or groove reserved line
on both sides, and scanning width is shown in table 5.
b) It shall perform scanning in the region of the central plate, probe along the
direction perpendicular to the plate rolling, and parallel line with distance not
more than 50 mm, or the probe along the vertical and parallel plate rolling
direction and grid line with distance not more than 100 mm. Scanning diagram
is shown in figure 3;
c) According to the requirements of contract, technical agreement or drawing
pattern, it also can use other forms for scanning;
d) When scanning is performed with double wafer straight probe, the moving
direction of the probe shall be vertical to its sound insulation layer.
Table 5 -- Width on edge of the plate or groove reserved line on both sides
Unit: mm
Plate thickness Regional width
< 50 50
≥ 60 ~ 100 75
≥ 100 100
Figure 3 -- Schematic chart of probe scanning
5.3.6.4 Testing of Angle probe shall be carried out in accordance with the provisions in
Annex D.
5.3.7 Judgment and quantitative of defect
5.3.7.1 It can be viewed as defect if one of two following cases are found under testing
standard sensitivity:
a) The first reflective wave (F1) of the defect has higher wave amplitude than
distance - wave amplitude curve; or when double wafer probe is used to test
plate with thickness less than 20 mm, the first reflective wave (F1) of the defect
is greater than or equal to 50 % of full scale of fluorescent screen;
b) The first reflection (B1) has lower wave amplitude than 50% of full scale of
fluorescent screen, namely B1 < 50 %.
5.3.7.2 Defect quantitative
5.3.7.2.1 Defect quantitative when double wafer straight probe is used for testing:
a) When double wafer straight probe is used for defect quantitative, the moving
direction probe shall be vertical to its sound insulation layer;
b) When plate thickness is less than or equal to 20 mm, move the probe to make
defect wave decline to 50 % of full scale of fluorescent screen under standard
Central scanning
of steel plate 100 % scanning region nearby
Central scanning
of steel plate 100 % scanning region nearby
Groove reserved line
Groove reserved line
sensitivity, and the center point of the probe is the boundary point of the defect;
c) When plate thickness is greater than 20 mm to 60 mm, move the probe to make
defect wave decline to distance - wave amplitude, and the center point of the
probe is the boundary point of the defect;
d) When boundary range of defect is determined in 5.3.7.1 b), move the probe to
make the first bottom face reflection wave lift to 50 % of full scale of fluorescent
screen under standard sensitivity or lift to distance - wave amplitude. For this
case, the center point of the probe is the boundary point of the defect.
5.3.7.2.2 Defect quantitative when single wafer straight probe is used for testing:
Single wafer straight probe shall be used to make defect quantitative based on method
in 5.3.7.2.1 c), d) and e), and it shall also record the defect reflection amplitude or
equivalent flat bottom hole diameter.
5.3.8 Evaluation method of defect size
5.3.8.1 Evaluation rules on defect indicated length
Rectangular frame parallel to plate rolling direction shall surround the defects, and its
side length shall be taken as indicated length of this defect.
5.3.8.2 Evaluation rules on indicated area of single defect
a) A defect shall accord with its indicated rectangular area as single indicated area
of this defect;
b) When adjacent spacing among many defects are lower than indicated length of
small defect nearby, it shall deal with in accordance with single defect, and the
defect indicated area is the sum of each defect area.
5.3.9 Plate quality grading
5.3.9.1 See table 6 and table 7 for plate quality grading, and table 6 and table 7 shall
be applied separately when quality grading is carried out specifically.
5.3.9.2 In the process of testing, testing personnel shall evaluate Grade V if there are
white spots, crack and other defects are found in the plate.
5.3.9.3 In the central testing area of the plate, the quality grading shall be determined
in accordance with the maximum allowed single defect indicated area and the
maximum allowed defect quantity within any testing area of 1 m × 1 m. If the testing
area is lower than 1 m × 1 m within the center of the whole plate, the maximum allowed
defect quantity can be converted based on proportion.
5.3.9.4 On the edge of the plate or groove reserved line on both sides of the detection
area, the quality grading shall be determined in accordance with the maximum allowed
single defect indicated length, the maximum allowed single defect indicated area and
the maximum allowed defect quantity within any testing area of 1 m. If the testing area
is lower than 1 m within the edge of the whole plate, the maximum allowed defect
quantity can be converted based on proportion.
Table 6 -- Quality grading in center testing area of standby plate for pressure
equipment
Unit: mm
Grade
The maximum allowed single
defect indicated area S or
equivalent flat bottom hole
diameter D
The maximum allowed defect quantity within any
testing area of 1 m × 1 m.
Evaluation scope of single defect
indicated area or equivalent flat
bottom hole diameter
Maximum
allowed
quantity
Double wafer straight probe is
used for testing: S ≤ 50
Double wafer straight probe is used
for testing: 20 < S ≤ 50 10 Or single wafer straight probe is
used for testing: D ≤ Φ5 + 8 dB
Or single wafer straight probe is
used for testing: Φ5 < D ≤ Φ5 + 8 dB
II
Double wafer straight probe is
used for testing: S ≤ 100
Double wafer straight probe is used
for testing: 50 < S ≤ 100
10 Or single wafer straight probe is
used for testing: D ≤ Φ5 + 14 dB
Or single wafer straight probe is
used for testing: Φ5 + 8 dB < D ≤ Φ5
+ 14 dB
III S ≤ 1000 100 < S ≤ 1000 15
IV S ≤ 5000 1000 < S ≤ 1000 20
V Exceeding grade IV
Note: when single wafer straight probe is used for testing and quality grading of defects (Grade
I and Grade II) were determined as shown in 5.3.7.1 b), the requirements are the same as
double wafer straight probe.
Table 7 -- Quality grading ion the edge or groove reserved line of testing area
of standby plate for pressure equipment
Unit: mm
Grade
Maximum
allowed
single
defect
indicated
length
Lmax
Maximum allowed
single defect
indicated area S or
equivalent flat bottom
hole diameter D
Maximum allowed defect quantity within
any testing area of 1 m
Evaluation scope of single defect
indicated length L or equivalent
flat bottom hole diameter
Maximum
allowed
quantity
I ≤ 20 Double wafer straight Double wafer straight probe is 2
probe is used for
testing: S ≤ 50
used for testing: 10 < L ≤ 20
Or single wafer
straight probe is used
for testing: D ≤ Φ5 + 8
dB
Or single wafer straight probe is
used for testing: Φ5 < D ≤ Φ5 +
8 dB
II ≤ 30
Double wafer straight
probe is used for
testing: S ≤ 100
Double wafer straight probe is
used for testing: 15 < L ≤ 30
3 Or single wafer
straight probe is used
for testing: D ≤ Φ5 +
14 dB
Or single wafer straight probe is
used for testing: Φ5 + 8 dB < D ≤
Φ5 + 14 dB
III ≤ 50 S ≤ 1000 25 < L ≤ 50 5
IV ≤ 100 S ≤ 2000 50 < S ≤ 100 6
V Exceeding grade IV
Note: When single wafer straight probe is used for testing and quality grading of defects
(Grade I and Grade II) were determined as shown in 5.3.7.1 b), the requirements are the
same as double wafer straight probe.
5.4 Ultrasonic testing method and quality grading of standby composite board
for pressure equipment
5.4.1 Scope
5.4.1.1 This article is applicable to ultrasonic testing method and quality grading of
standby composite board for pressure equipment with base material thickness of more
than or equal to 6 mm, such as stainless steel - steel, titanium - steel, aluminum - steel,
nickel - steel and copper - steel composite board.
5.4.1.2 This article is mainly used for ultrasonic testing for composite board base
material and sheathing interface combined status.
5.4.2 Testing principle
It can either generally perform testing from the substrate side, or choose testing from
sheathing side.
5.4.3 Probe selection
It shall adopt single wafer straight probe or double wafer straight probe with 2 MHz to
5 MHz, and the effective diameter of probe wafer shall be within the scope of 10 mm
to 25 mm.
5.4.4 Determination of sensitivity
5.4.4.1 The probe shall be placed to full combined position of the composite plate, and
the first regulated bottom echo height is 80 % of full scale of fluorescent screen. This
shall be taken as standard sensitivity.
5.4.4.2 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
5.4.5 Testing
Coupling method can use direct contact method or immersion method.
5.4.5.2 Scanning way
a) It shall perform 100 % scanning on the edge of the composite plate or groove
reserved line on both sides, and scanning width is shown in table 5.
b) It shall perform scanning in the region of the central composite plate, probe along
the direction perpendicular to the plate rolling, and parallel line with distance not
more than 50 mm, or the probe along the vertical and parallel plate rolling
direction and grid line with distance not more than 100 mm. Scanning diagram
is shown in figure 3;
c) According to the requirements of contract, technical agreement or drawing
pattern, it also can use other forms for scanning;
d) When scanning is performed with double wafer straight probe, the moving
direction of the probe shall be vertical to its sound insulation layer.
5.4.6 Measurement of uncombined area
When the first bottom echo height is 5 % less than full scale of fluorescent screen, and
there are obvious uncombined defect echoes existed (echo height ≥ 5 %), this position
shall be viewed as uncombined defect area. Move the probe to make the first bottom
echo lift to 40 % of full scale of fluorescent screen, at this moment, the probe center
point shall be taken as boundary point of uncombined defect area.
5.4.7 Uncombined evaluation method
5.4.7.1 Evaluation rules on uncombined indicated length
When uncombined boundary scope is determined, rectangular frame parallel to plate
rolling direction shall surround the uncombined defects, and its side length shall be
taken as indicated length of this defect. If single uncombined indicated length is less
than 25 mm, it is not required to record.
5.4.7.2 Evaluation rules on single uncombined area
a) An uncombined shall accord with its indicated rectangular area as this single
uncombined area;
b) When adjacent spacing among many uncombined are lower than 20 mm, it shall
deal with in accordance with single uncombined, and its area is the sum of each
uncombined area.
5.4.7.3 Evaluation of uncombined rate
Within any tested area of 1 m × 1 m, it shall be determined in accordance with
percentage occupying in uncombined area.
5.4.8 Quality grading
5.4.8.1 Within the 100 % scanning area on the edge of the composite board or groove
reserved line on both sides, when uncombined indicated length is greater than or equal
to 25 mm, it shall be confirmed as Grade IV.
5.4.8.2 Quality grading shall be according to provisions in table 8.
Table 8 -- Quality grading of composite board ultrasonic testing
Grade Single uncombined indicated length/mm
Single uncombined
area/cm2 Uncombined rate/%
I 0 0 0
II ≤ 50 ≤ 20 ≤ 2
III ≤ 75 ≤ 45 ≤ 5
IV Exceeding grade III.
5.5 Ultrasonic testing method and quality grading of standby carbon steel and
low ally steel forgings for pressure equipment
5.5.1 Scope
5.5.1.1 This article is applicable to ultrasonic testing method and quality grading of
standby carbon steel and low ally steel forgings for pressure equipment.
5.5.1.2 This article is not applicable to testing of circumferential angle probe for annular
and cylinder forgings with ratio of internal and external radius less than 65 %.
5.5.2 Testing principle
5.5.2.1 Testing shall be arranged after heat treatment, and before hole and platform
structure are machining. The surface roughness of tested face shall be Ra ≤ 6.3 μm.
5.5.2.2 Forgings shall generally be used with straight probe for testing, and annular
and cylinder forgings shall be added with angle probe for testing.
5.5.2.3 When testing thickness is less than or equal to 45 mm, it shall be performed
with double wafer straight probe. When testing thickness is more than 45 mm, it is
usually performed with single wafer straight probe.
5.5.2.4 When thickness of forgings testing direction exceeds 400mm, it shall be tested
from both relative end face.
5.5.3 Probe selection
5.5.3.1 Straight probe
5.5.3.1.1 Probe nominal frequency shall be in the range of 1 MHz to 5 MHz.
5.5.3.1.2 Wafer area of double wafer straight probe shall not be less than 150 mm2;
effective diameter of single wafer straight probe shall be within the rage of Φ10 mm to
40 mm.
5.5.3.2 Angle probe
5.5.3.2.1 The probe shall keep good contact with tested work piece. In the following
cases, curve test blocks shall be applied to regulate testing scope and standard
sensitivity:
a) When scanning is carried out on convex surface vertically (axially), the probe
wedge width shall one fifth greater than curvature radius of the tested surface;
b) When scanning is carried out on convex surface horizontally (circumferential),
the probe wedge length shall one fifth greater than curvature radius of the tested
surface;
5.5.3.2.2 The probe nominal frequency is 2 MHz to 5 MHz mostly, and the probe wafer
area is 80 mm2 to 625 mm2.
5.5.4 Reference block
5.5.4.1 Reference block shall conform to the provisions in 4.2.3.2.
5.5.4.2 Reference block can be made of by one of the following materials:
a) Excessive part of tested material (when the size is sufficient);
b) Material with same steel type and heat treatment status as the tested material;
c) Material with same or similar acoustic features as the tested material.
5.5.4.3 Reference block of single wafer straight probe
Single wafer straight probe shall use CS-2 test block to regulate standard sensitivity,
and its shape and size shall conform to provisions in figure 4 and table 9. It can also
use other reference block if necessary.
5.5.4.4 Reference block of double wafer straight probe
a) When testing thickness of work piece is less than 45 mm, it shall use CS-3
reference block;
b) The shape and size of CS-3 reference block shall meet figure 5 and table 10.
Figure 4 -- CS-2 reference block
Table 9 -- Size of CS-2 reference block
Unit: mm
SN of
test
block
Specification
of test block d L1 L2 D
S/N
of
test
block
Specification
of test block d L1 L2 D
1 25/2 2 25 50 ≥ 35 19 200/2 2 200 225 ≥ 100
2 25/3 3 25 50 ≥ 35 20 200/3 3 200 225 ≥ 100
3 25/4 4 25 50 ≥ 35 21 200/4 4 200 225 ≥ 100
4 50/2 2 50 75 ≥ 50 22 250/2 2 250 275 ≥ 110
5 50/3 3 50 75 ≥ 50 23 250/3 3 250 275 ≥ 110
6 50/4 4 50 75 ≥ 50 24 250/4 4 250 275 ≥ 110
All
7 75/2 2 75 100 ≥ 60 25 300/2 2 300 325 ≥ 120
8 75/3 3 75 100 ≥ 60 26 300/3 3 300 325 ≥ 120
9 75/4 4 75 100 ≥ 60 27 300/4 4 300 325 ≥ 120
10 100/2 2 100 125 ≥ 70 28 400/2 2 400 425 ≥ 140
11 100/3 3 100 125 ≥ 70 29 400/3 3 400 425 ≥ 140
12 100/4 4 100 125 ≥ 70 30 400/4 4 400 425 ≥ 140
13 125/2 2 125 150 ≥ 80 31 500/2 2 500 525 ≥ 155
14 125/3 3 125 150 ≥ 80 32 500/3 3 500 525 ≥ 155
15 125/4 4 125 150 ≥ 80 33 500/4 4 500 525 ≥ 155
16 150/2 2 150 175 ≥ 85
17 150/3 3 150 175 ≥ 85
18 150/4 4 150 175 ≥ 85
Figure 5 -- CS-3 reference block
Table 10 -- Size of CS-3 reference block Unit: mm
SN of test
block
Hole
diameter
Testing distance L
1 2 3 4 5 6 7 8 9
1 Φ2
5 10 15 20 25 30 35 40 45 2 Φ3
3 Φ4
5.5.4.5 When curvature radius of work piece tested surface is less than or equal to 250
mm, it shall use curve surface reference blocks (the test block curvature radius is within
0.7 times to 1.1 times of work piece curvature radius) to adjust standard sensitivity, or
CS-4 comparison test is used to measure sound energy loss caused by different
curvature, and its shape and size shall be according to figure 6.
All
Figure 6 -- CS-4 reference block
5.5.4.6 See provisions in JB/T 8428 and GB/T 11259 for manufacturing requirements
of CS-2, CS-3 and CS-4 reference block.
5.5.5 Determination of sensitivity
5.5.5.1 Determination of standard sensitivity of single wafer straight probe
Use CS-2 or CS-4 test block to test a group of flat bottom hole of Φ2 mm with different
testing distance in order (at least three), draw distance - amplitude curve of single
wafer straight probe, and take it as standard sensitivity. When the thickness of tested
position is 3 times larger than near-field zone length of probes and the tested surface
is parallel to the bottom surface, it can also adopt bottom wave calculation method to
determine standard sensitivity.
5.5.5.2 Determination of standard sensitivity of double wafer straight probe
Use CS-3 test block to test a group of flat bottom hole of Φ2 mm with different testing
distance in order (at least three). Draw distance - amplitude curve of double wafer
straight probe, and take it as standard sensitivity.
5.5.5.3 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
5.5.6 Testing
5.5.6.1 Coupling method
All R is 0.7 times to 1.1 times of
work piece curvature radius
Coupling way can generally adopt direct contact method.
5.5.6.2 Sensitivity compensation
Coupling compensation, attenuation compensation and surface compensation shall be
conducted in accordance with actual situation in time of testing.
5.5.6.3 The determination of work piece material attenuation coefficient
a) In the area where the work piece are in good condition without defect, choose
three representative where tested surfaces is parallel to the bottom surface,
adjust the instrument to make the first bottom echo amplitude (B1) or the Nth time
bottom echo amplitude (Bn) to be 50 % of full scale, record instrument gain or
attenuator readings at this time, readjust the instrument gain or attenuator to
make the second bottom echo amplitude or the mth time bottom echo amplitude
(B2 or Bm) to be 50 % of full scale, and the reading difference between the two
gains or attenuator readings is (B1 - B2) or (Bn - Bm) (not considering bottom
reflection loss).
b) When base material nominal thickness is 3 times less than near-field zone of
probe (t < 3N), the attenuation coefficient (meeting t < 3N/t, m < n) shall be
calculated based on formula (1):
α = [(Bn - Bm) - 201g(m/n)]/2 (m - n)t ……………………… (1)
where:
α - attenuation coefficient, dB/m (single travel);
(Bn - Bm) - reading difference between the two gains or attenuator readings, dB;
t - tested thickness of the work piece, m;
N - near-field zone length of single wafer straight probe, m;
m, n - times of bottom reflection.
c) When base material nominal thickness is greater than or equal to 3 times of near-
field zone of probe (t ≥ 3N), the attenuation coefficient shall be calculated based
on formula (2):
α = [(B1 - B2) - 6]/2t ………….…………...……. (2)
where:
(B1 - B2) - reading difference between the two gains or attenuator readings, dB;
And other symbols have the same meaning as b).
d) The average value of three attenuation coefficients on the work piece is
attenuation coefficient of this work piece.
5.5.6.4 Scanning method
5.5.6.4.1 Testing with straight probe
a) It shall perform 100 % scanning by moving probe from two mutual vertical
direction on the tested surface. The main testing direction is shown in figure 7;
b) When scanning is made by double wafer straight probe, the moving direction of
the probe shall be perpendicular to its sound isolation layer.
c) According to the requirements of contract, technical agreement or drawing
pattern, it also can use other forms for scanning, such as parallel line or grid line
scanning with certain intervals.
5.5.6.4.2 Testing with angle probe
Testing with angle probe shall be according to requirements of Annex E.
5.5.7 Determination of defect equivalent
5.5.7.1 When depth of tested defect is greater than or equal to 3 times of near-field
zone of probe, it can use AVG curve calculation method to determine the defect
equivalent. For defect with 3 times of near-field zone, it can apply distance - amplitude
curve to determine the defect equivalent. It can also adopt other equivalent method to
determine.
Explanation:
↑ - testing direction;
※ - reference testing direction.
Figure 7 -- Testing direction (vertical testing method)
5.5.7.2 When calculation method is adopted to determine the defect equivalent, it shall
be revised if material attenuation coefficient is more than 4 dB/m.
5.5.7.3 When the distance - amplitude curve is used to determine the defect equivalent,
it shall be revised if attenuation coefficient difference between the reference blocks
and work piece material is more than 4 dB/m.
5.5.8 Evaluation on quality classification and grading
5.5.8.1 See table 11 for defect quality grading.
5.5.8.2 When inspectors determine that reflected signal is white spot, crack and other
harmful defects, the forging quality is determined as Grade V.
Table 11 -- Quality grading of ultrasonic testing for forgings Unit: mm
Grade I II III IV V
Single defect
equivalent flat
bottom hole
diameter
≤ Φ4 ≤ Φ4 + 6 dB ≤ Φ4 +12 dB ≤ Φ4 + 18 dB > Φ4 + 18 dB
Bottom wave
decline amount
caused by defect
BG/BF
≤ 6 dB ≤ 12 dB ≤ 18 dB ≤ 24 dB > 24 dB
Grouped area
defect equivalent
diameter
≤ Φ2 ≤ Φ3 ≤ Φ4 dB ≤ Φ4 + 4dB > Φ4 + 4 dB
Percentage of
grouped zone
defect area
occupying total
tested area %
0 ≤ 5 ≤ 10 ≤ 20 > 20
Note1: bottom wave caused by defect is only applicable to defect with acoustic travel larger than
length in near-field zone.
Note2: defect grading with different types in the table shall be used independently.
Note3: grouped zone defect area refers to grouped zone defect with reflection amplitude greater
than or equal to Φ2 of equivalent flat bottom hole diameter.
5.6 Ultrasonic testing method and quality grading of standby steel bolt billet for
pressure equipment
5.6.1 Scope
5.6.1.1 This article is applicable to ultrasonic testing method and quality grading of
standby steel bolt billet for pressure equipment with diameter greater than or equal to
M36.
5.6.1.2 Ultrasonic testing method for austenite stainless steel bolt billet shall be carried
out in accordance with this article and quality grading shall accord with this article.
5.6.1 Testing principle
Testing is generally conducted after heat treatment, and appearance roughness of
tested surface is Ra ≤ 6.3 μm.
5.6.3 Probe selection
It shall adopt single wafer straight probe or double wafer straight probe with 2 MHz to
5 MHz.
5.6.4 Reference block
5.6.4.1 When single wafer straight probe is used for axial testing, the size and shape
of reference block shall meet provision in 5.5.4.3.
5.6.4.2 When double wafer straight probe is used for axial testing, the size and shape
of reference block shall meet provision in 5.5.4.4.
5.6.4.3 In time of radial test, it shall probe with small wafer size. When radius of bolt
billet curvature is less than 100 mm, it shall use shape and size of reference block as
sown in figure 8 and table 12.
Figure 8 -- Bolt billet radial testing reference block
5.6.5 Determination of sensitivity
5.6.5.1 Determination of standard sensitivity of single wafer straight probe
When axial testing, use CS-2 test block to test a group of flat bottom hole of Φ2 mm
with different testing depth in order (at least three) based on testing range, draw
distance - amplitude curve of single wafer straight probe, and take it as standard
sensitivity. When radial testing, use CS-2 test block or test block as shown in figure 8
to test a group of flat bottom hole of Φ2 mm with different testing depth in order (at
least three) based on testing range or curve radius, draw distance - amplitude curve
of single wafer straight probe, and take it as standard sensitivity.
Table 12 -- Size of bolt billet radial testing reference block Unit: mm
Reference block
radius R A B c D E
Applicable work piece
curvature radius range
90 15 30 45 90 135 82 ~ 99
75 12 24 38 76 114 67 ~ 81
60 10 20 30 60 90 54 ~ 66
48 8 16 24 48 72 43 ~ 53
38 6 12 20 40 60 36 ~ 42
32 4 8 16 25 40 29 ~ 35
25 4 8 16 24 32 22 ~ 28
20 4 8 14 20 30 18 ~ 22
5.6.5.12 Determination of standard sensitivity of double wafer straight probe
When axial testing, use CS-2 test block to test a group of flat bottom hole of Φ2 mm
with different testing depth in order (at least three) based on testing range, draw
distance - amplitude curve of double wafer straight probe, and take it as standard
sensitivity. When radial testing, use CS-3 test block or test block as shown in figure 8
to test a group of flat bottom hole of Φ2 mm with different testing depth in order (at
least three) based on testing range or curve radius, draw distance - amplitude curve
of double wafer straight probe, and take it as standard sensitivity.
5.6.5.3 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
5.6.6 Testing
5.6.6.1 Coupling method
Coupling way can generally adopt direct contact method.
5.6.6.2 Sensitivity compensation
Coupling compensation, attenuation compensation and surface compensation shall be
conducted in accordance with actual situation in time of testing.
5.6.6.3 Scanning method
5.6.6.3.1 Radial testing shall be performed with scanning according to the spiral line
or along the circumference, the travel shall be overlapping, and scanning surface shall
include the whole cylindrical surface.
5.6.6.3.2 Axial testing be performed with scanning from both ends of bolt billet, to avoid
edge effect influencing testing result as much as possible.
5.6.7 Determination of defect equivalent
Distance-amplitude curve is generally adopted to determine defect equivalent.
5.6.8 Quality grading
5.6.8.1 See table 13 for quality grading of single defect.
5.6.8.2 See table 14 for quality grading of bottom wave decline amount caused by
defect.
5.6.8.3 It shall be used respectively as independent grade when defect grade is
assessed in accordance with table 13 and table 14.
5.6.8.4 When inspectors determine the defect as white spot, crack and other harmful
defects, the quality grading of bolt billet is determined as Grade V.
Table 13 -- Quality grading of single defect Unit: mm
Grade I II III IV V
Defect equivalent flat
bottom hole diameter ≤ Φ2 ≤ Φ3 ≤ Φ4 ≤ Φ4 + 6 dB > 4 + 6 dB
Table 14 -- Quality grading of bottom wave decline amount caused by defect
Unit: dB
Grade I II III IV V
Bottom wave decline
amount caused by defect
BG/BF
≤ 6 ≤ 12 ≤ 18 ≤ 24 > 24
Note: this table is only applicable to defect with acoustic travel larger than length in near-field
zone.
5.7 Ultrasonic testing method and quality grading of standby austenite steel
forgings for pressure equipment.
5.7.1 Scope
5.7.1.1 This article is applicable to ultrasonic testing method and quality grading of
standby austenite steel forgings and duplex austenite - ferritic for pressure equipment
with diameter greater than or equal to M36.
5.7.1.2 Ultrasonic testing method and quality grading for nickel alloy forgings shall be
carried out in accordance with this article
5.7.2 Testing principle
5.7.2.1 When forgings are processed into appropriate testing appearance after heat
treatment, ultrasonic testing shall be carried out before finish machining.
5.7.2.2 Testing surface roughness shall be Ra ≤ 6.3 μm, and the tested surface shall
be no oxide coating, paint and dirt etc.
5.7.2.3 It shall generally conduct longitudinal wave detection for straight probe. And
angle probe detection shall be carried out for cylinder forgings and ring forgings.
5.7.3 Probe
5.7.3.1 The nominal frequency of the probe is 1 MHz to 2.5 MHz.
5.7.3.2 Wafer diameter of straight probe is Φ10 mm to Φ40 mm, and wafer area of
straight probe is about 300 mm2 to 625 mm2.
5.7.3.3 Refraction of angle probe (value K) is 35 to 63 degree in general (K0.7 to K2).
5.7.3.4 In order to accurately measure defect, other probes can be used if necessary.
5.7.4 Test block
5.7.4.1 Reference block shall meet provisions in 4.2.3.2.
5.7.4.2 The grain size and the acoustic characteristics of reference blocks shall be
close to the tested forging, and the attenuation coefficient difference between these
two shall not be more than 4 dB/m.
5.7.4.3 It shall prepare several sets of austenite steel forgings for reference blocks with
different grain size, so as to make reasonable comparison to attenuation test block in
the defect zone.
5.7.4.4 The shape and the size of reference block is shown in figure 9 and table 15.
Figure 9 -- Test block of austenite steel forgings
Table 15 -- Size of test block of austenite steel forgings Unit: mm
All
Φ3 Φ6 Φ10 Φ13
L D L D L D L D
20 50 20 50 20 50 20 50
40 50 50 50 50 50 50 50
60 50 80 50 100 60 100 60
80 50 120 60 150 80 150 80
— — 160 80 200 80 200 80
— — 200 80 250 100 250 100
— — — — 300 100 300 100
— — — — — — 400 150
— — — — — — 500 150
— — — — — — 600 200
5.7.4.5 When conditions allowed, one a more appropriate flat bottom hole a V-shaped
groove can be processed to representative positions on the forgings, to replace
reference block, so as to conduct calibration of sensitivity.
5.7.5 Determination of sensitivity
5.7.5.1 When the thickness of tested forgings is less than or equal to 600 mm,
calibration shall be carried out on flat bottom hole test block with proper thickness and
equivalent diameter in accordance with order forging thickness and required quality
grade, draw distance-amplitude curve based on actual measured value, and take it as
standard sensitivity.
5.7.5.2 When the thickness of tested forgings is more than 600 mm, the bottom wave
shall be adjusted to 80 % of full scale on position without defect, and take it as standard
sensitivity. If the tested surface is not parallel to the bottom reflection surface, a Φ3
mm flat bottom test block can be used as distance-amplitude curve, and take it as
standard sensitivity.
5.7.5.3 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
5.7.6 Testing
5.7.6.1 Coupling method
Coupling way can generally adopt direct contact method.
5.7.6.2 Sensitivity compensation
Coupling compensation, attenuation compensation and surface compensation shall be
conducted in accordance with actual situation in time of testing.
5.7.6.3 Testing with straight probe
5.7.6.3.1 All tested areas of the forgings shall be performed with testing from two
vertical direction mutually as much as possible, and the tested distance shall be half
of the thickness.
5.7.6.3.2 When disk-shaped or pie-shaped forgings are tested, straight probe shall be
used to conduct testing from at least one flat surface, and scanning shall be carried
out from circumference surface if possible.
5.7.6.3.3 When cylinder forgings are tested, for cylinder forgings or annular forgings,
testing can be conducted from the whole external surface (side face or circumference
surface) with straight probe. When the ratio of length and diameter exceeds 6 or the
axial length is more than 600 mm, straight probe shall be used to conduct axial testing
from both end surface on the largest scope as possible. If testing on both ends fails to
exceed half of the length due to attenuation and other causes, the straight probe can
be replaced by angle probe to conduct axial testing.
5.7.6.4 Testing with angle probe
Testing for austenite steel forgings with angle probe shall be conducted in accordance
with requirements of Annex F.
5.7.7 Defect record
5.7.7.1 Because there are defects, the bottom wave under standard sensitivity will be
decreased to a position below 25 % of full scale.
5.7.7.2 Defect amplitude is at a position above distance-amplitude curve.
5.7.8 Quality grading
5.7.8.1 Please see table 16 for quality grading for single wafer straight probe or double
wafer straight probe.
5.7.8.2 Please see table 17 for quality grading for testing with angle probe.
5.7.8.3 When quality is graded specifically, table 16 and table 17 shall be used
separately.
Table 16 -- Quality grading of testing with straight probe Unit: mm
Base material nominal
thickness ≤ 80 > 80 ~ 200 > 200 ~ 300 > 300 > 600
Quality grade I II I II I II I II I II
Defect equivalent flat
bottom hole diameter or
amplitude after bottom
wave decline caused by
≤ Φ3 > Φ3 ≤ Φ6 > Φ6 ≤ Φ10
Φ10
Φ13
Φ13 ≥ 5 % < 5 %
defect
Note: Base material nominal thickness mainly refers to size in pressure bearing direction; for
cylinder or annular forgings, base material nominal thickness is the cylinder thickness; for pie-
shaped or similar forgings, base material nominal thickness is the minimum thickness.
Table 17 -- Quality grading of testing with angle probe
Grade I II
Defect
amplitude
Defect amplitude is lower than
distance-amplitude curve of V-shaped
groove test block. For this case, V-
shaped groove is 3 % of nominal wall
thickness of work piece (it is 3 mm at
largest).
Defect amplitude is lower than
distance-amplitude curve of V-shaped
groove test block. For this case, V-
shaped groove is 5 % of nominal wall
thickness of work piece (it is 6 mm at
largest).
5.8 Ultrasonic testing method and quality grading of standby seamless steel
pipe for pressure equipment
5.8.1 Scope
5.8.1.1 This article is applicable to ultrasonic testing method and quality grading of
standby carbon steel, low alloy steel, austenitic stainless steel and austenite - iron
body duplex stainless steel seamless steel pipe for pressure equipment with external
diameter not less than 12 mm.
5.8.1.2 This article shall neither apply to steel pipe circumferential direct contact angle
probe testing with the ratio of internal and external diameter less than 65 %, and of the
steel pipe circumferential immersion method transverse wave testing with the ratio of
internal and external diameter less than 60 %, nor apply to ultrasonic testing with defect
in layers.
5.8.2 Testing principle
Unless it is required to detect transverse defect, testing is generally conducted to the
longitudinal defects. Through negotiation of both parties, testing on longitudinal or
transverse defects can be carried out at one direction on the steel pipe.
5.8.3 Testing equipment
5.8.3.1 Testing equipment is composed of ultrasonic detector, probe, detecting device,
mechanical transmission device, separation devices and other auxiliary equipment etc.
5.8.3.2 Detection can use line focus or point or focusing probe. A single probe’s
piezoelectric wafer length or diameter shall be no greater than 25 mm.
5.8.3.3 Detection device
Detection device shall be equipped with high-precision adjusting mechanism for
relative steel pipe position of the probe, and can be reliably locked up or can achieve
good mechanical trace, to ensure that the beam keep unchanged incidence condition
for steel pipe under dynamic situation.
5.8.3.4 Transmission device
Transmission device shall make the steel tube passing through the detection device
with uniform speed and can guarantee the steel pipe and the detection device has
good concentricity during detection.
5.8.3.5 Separation device
Separation device shall reliably detect qualified and unqualified steel pipes separately.
5.8.4 Reference blocks
5.8.4.1 Reference blocks shall be manufactured by choosing steel pipes with same
specification as the tested steel pipe, and same or similar material, heat treatment
process and surface status as the tested pipe. The length of the reference block shall
meet requirements of testing method and detection equipment.
5.8.4.2 Artificial reflector
5.8.4.2.1 The shape of artificial reflector
Artificial reflector used for testing longitudinal and transverse defects shall be
longitudinal groove parallel to the pipe axis and transverse groove vertical to the pipe
axis respectively. Both cross section shape can be rectangular or V-shaped. See figure
10 for diagram of artificial reflector. Two side faces in the rectangular groove shall be
parallel to and vertical to the groove bottom mutually. When the electric erosion method
is used for processing, it is allowed the bottom and the bottom corner of the groove to
be circular slightly. Angle of V-shaped groove shall be 60 degree. Both parties of supply
and demand shall negotiate to select shape of artificial reflector during testing.
5.8.4.2.2 Position of artificial reflector
A longitudinal groove shall be processed to the external surface in the center of
reference block or internal and external surface of end region. Nominal size of three
grooves are the same. When the inner diameter of the steel pipe is less than 25 mm,
inner wall longitudinal groove cannot be processed. A transverse groove shall be
processed to the external surface in the center of sample or internal and external
surface of end region. Nominal size of three grooves are the same. When the inner
diameter of the steel pipe is less than 50mm, inner wall transverse groove cannot be
processed.
5.8.4.2.3 Size of artificial reflector
The size of the artificial reflector is divided into 3 levels according to table 18. Specific
levels shall be conducted in accordance with relevant standard of steel pipe products.
If there are no provisions for product standards, both parties of supply and demand
shall negotiate and determine.
Table 18 -- Size of artificial reflector Unit: mm
Grade
Depth
Width b
Length
h/t
(%) Minimum
Allowable
error Longitudinal Transverse
I 5 0.20 ±15 % Not twice greater
than the depth,
and the maximum
value is 1.5.
40
40 or 50 %
of perimeter,
which one is
smaller.
II 8 0.40 ±15 %
III 10 0.40 ±15 %
Note: the maximum depth of artificial reflector is 3.0.
5.8.4.2.4 Manufacture and measurement
Artificial reflector can be processed with electric erosion, mechanical or other methods.
Obvious mark or serial number shall be attached to the reference sample. The depth
of artificial reflector can be measured with optical method, concealed method or other
methods.
a) Schematic diagram of transverse artificial reflector
All
Artificial reflector - rectangular groove
Artificial reflector - V-shaped groove
b) Schematic diagram of longitudinal artificial reflector
Explanation:
h - depth of artificial reflector, mm;
b - width of artificial reflector, mm.
Figure 10 -- Diagram of artificial reflector
5.8.5 Determination of sensitivity
5.8.5.1 When direct contact method is used for testing, echo amplitude of inner wall
artificial reflector on the reference block can be directly adjusted to 80 % of full scale
of fluorescent screen, and then move the probe to find out the maximum echo of outer
wall artificial reflector and mark on the displayed screen. Connect two points to
generate distance-amplitude curve and take as standard sensitivity. When there is no
inner wall artificial reflector on the reference block due to pipe diameter, the first echo
and the second echo of outer wall artificial reflector can be used to draw distance-
amplitude curve.
5.8.5.2 Standard sensitivity of immersion method can be determined by the following
methods:
a) Water layer distance shall be determined based on the focal length of the
focusing probe;
Artificial reflector - rectangular groove
Artificial reflector - V-shaped groove
All
b) In time of adjustment, rotate the pipe with proper speed on one side, and slowly
tilt the probe’s center on other side to make echo amplitude generated from inner
and outer surface artificial reflector of the reference block up to 50 % of full scale
of fluorescent screen, and take it as standard sensitivity;
c) When the internal and external wall artificial reflector signal use the same alarm
gate, the alarm sensitivity of the detector shall be set up in accordance with the
lower amplitude signal between signals of the internal and external wall and
circumferential signals at different locations. When the internal and external wall
artificial reflector signal use different alarm gates, the alarm sensitivity of the
detector shall be set up in accordance with the lower amplitude signal of
circumferential signals at different locations. At the same time, the width of both
gates shall meet alarm requirements for defect signals at each position inside
the pipe wall.
5.8.5.3 The scanning sensitivity is generally 6 dB higher than standard sensitivity.
5.8.6 Testing
5.8.6.1 Testing of steel pipe can be conducted with immersion method or direct contact
method in accordance with specification of the steel pipe.
5.8.6.2 When test block is used to regulate testing, coupling difference between test
block and tested surface of steel pipe shall be considered.
5.8.6.3 Angle probe is used for testing under status when the probe and steel probe is
moving relatively. In time of automatic or manual testing, it shall ensure sound beam
can scan all surface of the steel pipe. In time of automatic testing, it cannot conduct
effective testing for both ends of the steel pipe, and this area is viewed as blink area
of automatic testing. It shall adopt effective method to test this area, such as manual
method.
5.8.6.4 When longitudinal defect is tested, the sound beam shall be spread along with
circumferential direction (see figure 11); when transverse defect is tested, the sound
beam shall be spread along with axial direction (see figure 12). Testing of longitudinal
and transverse defect shall be conducted on opposite direction of the steel pipe.
Figure 11 -- Circumferential spread of sound beam inside the pipe wall
Figure 12 -- Axial spread of sound beam inside the pipe wall
5.8.6.5 The screw pitch of probe corresponding to steel pipe screw feed shall ensure
when the ultrasonic beam can conduct 100 % scanning on the steel pipe, the coverage
rate shall not be less than 15 %.
5.8.6.6 Automatic testing shall ensure dynamic testing, and the maximum reflection
amplitude difference of internal and external artificial reflector shall not exceed 2 dB.
5.8.7 Defect record
5.8.7.1 When direct contact method is used for testing, echo amplitude shall be greater
than or equal to 50 % defect of corresponding reference block, artificial reflector
distance - amplitude curve.
5.8.7.2 When immersion method is used for testing, echo amplitude shall be greater
than or equal to 50 % defect of echo amplitude generated by internal and external
surface artificial reflector of corresponding reference block.
5.8.8 Quality grading
5.8.8.1 Quality grading of seamless steel pipe shall be according to provisions in table
19.
5.8.8.2 Non-conforming products can be processed once again, and it shall accord
with testing and quality grade rating in accordance with this article after processing.
Table 19 -- Quality grading for ultrasonic testing of seamless steel pipe
Grade Allowable defect echo amplitude Direct contact method Immersion method
Lower than 50 % of corresponding
reference block, artificial reflector
distance - amplitude curve, namely
Hd < 50 % DAC
Lower than 50 % of echo amplitude
generated by internal and external
surface artificial reflector of
corresponding reference block, namely <
50 % Hr
II
Lower than corresponding
reference block, artificial reflector
distance - amplitude curve, namely
50 % DAC ≤ Hd < DAC
Lower than 50 % of echo amplitude
generated by internal and external
surface artificial reflector of
corresponding reference block, namely
50 % Hr ≤ Hd< Hr
III
Greater than or equal to
corresponding reference block,
artificial reflector distance -
amplitude curve, namely Hd ≥ 50 %
DAC
Greater than or equal to echo amplitude
generated by internal and external
surface artificial reflector of
corresponding reference block, namely
Hd ≥ Hr
Note: Hd refers to defect echo amplitude, and Hr refers to echo amplitude generated by
internal and external surface artificial reflector of reference block with immersion method.
5.8.9 Acceptance requirements
The acceptance requirements of seamless steel pipe shall be according to related
technical files.
6 Ultrasonic testing method and quality grading of
welded joint for pressure equipment
6.1 Scope
6.1.1 This chapter specified ultrasonic testing method and quality grading of welded
joint for pressure equipment made by ferritic steel, and its applicable scope and use
principle are shown in table 20.
6.1.2 Other fine crystal isotropic and low attenuation metal materials can be conducted
in accordance with provisions in this chapter, but the change of acoustic characteristics
of materials shall be considered.
6.1.3 Ultrasonic testing method and quality grading of weld cladding layer for pressure
equipment shall be performed in accordance with provisions in Annex G.
6.1.4 Ultrasonic testing method and quality grading of butt joint for pressure equipment
made by aluminum and aluminum alloy and titanium shall be performed in accordance
with provisions in Annex H.
6.1.5 Ultrasonic testing method and quality grading of butt joint for pressure equipment
made by austenite stainless steel shall be performed in accordance with provisions in
Annex H.
6.1.6 Ultrasonic testing method related to supporting part and structural piece of
pressure equipment shall be performed in accordance with provision in this chapter.
Table 20 -- Applicable scope and use principle for ultrasonic testing of welded
joint for steel-made pressure equipment
Unit: mm
Type of
pressure
equipment
Type of
welded joint
Base
material
nominal
thickness
Diameter of tested surface Testing method
Quality
grading
Boiler,
pressure
container
Cylinder (or
end socket)
butt joint
≥ 6 ~ 500
≥ 500, when longitudinal butt joint,
ratio of inner and outer diameter ≥
70 %.
6.3
6.5.1
≥ 100 ~ 500, longitudinal butt joint,
and ratio of inner and outer
diameter ≥ 70 %.
Annex
≥ 159 ~ 500, circular butt joint Annex K
Connecting
pipe (or end
socket)
Fillet joint
≥ 6 ~ 500
Plug-in type: cylinder (or end
socket) ≥ 500, and ratio of inner
and outer diameter ≥ 70 % nominal
diameter of connecting pipe ≥ 80.
Placement-type: cylinder (or end
socket) ≥ 300, and nominal
diameter of connecting pipe ≥ 100.
Annex
T-shaped
welded joint ≥ 6 ~ 300 —
Annex
Pipe
circular butt
joint
≥ 6 ~ 150 Outer diameter ≥ 500 6.3 6.5.2
≥ 6 ~ 150 Outer diameter ≥ 159 ~ 500 Annex K 6.5.2
≥ 6 ~ 50 Outer diameter ≥ 32 ~ 159 6.4 6.5.2
≥ 4 ~ 6 Outer diameter ≥ 32 6.4 6.5.2
Pipe
longitudinal
butt joint
≥ 6 ~ 150
Outer diameter ≥ 500, and ratio of
internal and external diameter ≥
70 %.
6.3 6.5.2
Outer diameter ≥ 100 ~ 500, and
ratio of internal and external
diameter ≥ 70 %.
Annex
J 6.5.2
Pressure
pipe
Circular butt
joint
≥ 6 ~ 150 Outer diameter ≥ 500 6.3 6.5.3
≥ 6 ~ 150 Outer diameter ≥ 159 ~ 500 Annex K 6.5.3
≥ 6 ~ 50 Outer diameter ≥ 32 ~ 159 6.4 6.5.3
≥ 4 ~ 6 Outer diameter ≥ 32 6.4 6.5.3
Longitudinal
butt joint ≥ 6 ~ 150
Outer diameter ≥ 500, and ratio of
internal and external diameter ≥
70 %.
6.3 6.5.3
Outer diameter ≥ 100 ~ 500, and
ratio of internal and external
diameter ≥ 70 %.
Annex
J 6.5.3
6.2 Process files of ultrasonic testing of welded joint for pressure equipment
Process files of ultrasonic testing of welded joint shall also include related factors listed
in table 21, in addition to meet requirements in 4.3.
Table 21 -- Related factors involved with process procedure of ultrasonic
testing of welded joint
S/N Content of related factors
1 Geometry shape of welded joint, including work piece specification, thickness, size
and product form (such as plate welding, forge welding etc.)
2 Welding method, welding process (such as groove type, angle etc.)
3 Grade of testing technology
4 Testing of parent material
5 Testing time (such as after welding or heat treatment or pressure resistance test)
6 Testing zone (scope etc.)
7 Additional testing (if necessary) and requirements
8 Acceptance grade (quality grade)
6.3 Ultrasonic testing method of I type welded joint for pressure equipment
6.3.1 Scope
This article is applicable to ultrasonic testing of I type welded joint, and see table 22
for scope of I type welded joint.
Table 22 -- Applicable scope of ultrasonic testing of I type welded joint
Unit: mm
Type of
pressure
equipment
Type of
welded joint
Base
material
nominal
thickness t
Diameter of tested surface
Testing
technology
grade
requirement
Boiler,
pressure
container
Cylinder (or
end socket)
butt joint
≥ 6 ~ 500
≥ 500, when longitudinal butt joint,
ratio of inner and outer diameter ≥
70 %.
6.3.2
≥ 100 ~ 500, longitudinal butt joint,
and ratio of inner and outer
diameter ≥ 70 %.
6.3.2
≥ 159 ~ 500, circular butt joint 6.3.2
Connecting
pipe (or end
socket)
Fillet joint
≥ 6 ~ 500
Plug-in type: cylinder (or end
socket) ≥ 500, and ratio of inner
and outer diameter ≥ 70 %.
Nominal diameter of connecting
pipe ≥ 80.
Placement-type: cylinder (or end
socket) ≥ 300, and nominal
diameter of connecting pipe ≥ 100.
6.3.2
T-shaped
welded joint ≥ 6 ~ 300 — 6.3.2
Pipe
circular butt
joint
≥ 6 ~ 150 Outer diameter ≥ 159 6.3.2
Pipe
longitudinal
butt joint
≥ 6 ~ 150
Outer diameter ≥ 100, and ratio of
internal and external diameter ≥
70 %.
6.3.2
Pressure
pipe
Circular butt
joint ≥ 6 ~ 150 Outer diameter ≥ 159 —
Longitudinal
butt joint ≥ 6 ~ 150
Outer diameter ≥ 100, and ratio of
internal and external diameter ≥
70 %.
6.3.2 Technical grade of ultrasonic testing
6.3.2.1 Technical grade of ultrasonic testing is divided into Grade A, Grade B and
Grade C.
6.3.2.2 Selection of technical grade of ultrasonic testing
The selection of technical grade of ultrasonic testing shall meet related specification of
manufacturing and installation, as well as provisions of standard and design drawing.
Ultrasonic testing when welded joint for pressure equipment is manufactured and
installed, shall generally adopt Grade B ultrasonic testing technology to conduct testing.
Welded joint for important equipment can adopt Grade C ultrasonic testing technology
to conduct testing.
6.3.2.3 General requirements of different testing technology grade
6.3.2.3.1 See Annex N for specific requirements for ultrasonic testing with different
types of welded joint.
6.3.2.3.2 Grade A testing
Grade A is applicable to testing welded joint with base material nominal thickness of 6
mm to 40 mm. A kind of refraction angle (value K) probe can use direct wave method
and primary reflection wave method to make testing on single and double side of
welded joint. If condition limited, it can choose to test single side of double face or
single side of single face. It does not require for testing of transverse defect in general.
6.3.2.3.3 Grade B testing
a) Grade B is applicable to testing welded joint with base material nominal thickness
of 6 mm to 200 mm;
b) The welded joint would conduct testing for transverse defect in general;
c) For welded joint which shall conduct testing for double side of double face in
accordance with requirements in Annex N, it shall add angle probe to conduct
testing for near-surface defect if geometry condition limited or testing for double
side of single face is selected due to existence of weld cladding layer (or
composite layer).
6.3.2.3.4 Grade C testing
a) Grade C is applicable to testing welded joint with base material nominal thickness
of 6 mm to 500 mm;
b) The excess weld metal of welded joint shall be rubbed down when Grade C is
used for testing. For parent material area scanning by angle probe of welded
joint, straight probe shall be used for testing, and the testing method shall be
performed in accordance with provisions in 6.3.7.
c) Welded joint with base material nominal thickness greater than 15mm shall
conduct testing for double sides of double face, and t shall add angle probe to
conduct testing for near-surface defect if geometry condition limited or testing for
double side of single face is selected due to existence of weld cladding layer (or
composite layer);
d) For weld seam with narrow clearance whose groove angle is lower than 5 degree,
if shall add effective method to testing and groove surface parallel defect if
possible;
e) For butt joint with base material nominal thickness greater than 40 mm, it shall
add testing made by straight probe;
f) Welded joint shall conduct testing for transverse defect.
6.3.2.3.5 When two or more kinds of different refraction (value K) angle probe are used
for testing, the refraction angle difference between probes shall not be smaller than 10
degree.
6.3.3 Test block
6.3.3.1 Standard test block
6.3.3.1.1 Preparation of standard test block shall comply with provisions in 4.2.3.1.
6.3.3.1.2 The standard test block used in this article is CSK-IA. And its shape and size
shall comply with the provisions in figure 13 respectively.
6.3.3.2 Reference blocks
6.3.3.2.1 Preparation of reference block shall comply with provisions in 4.2.3.2.
6.3.3.2.2 The reference block used in this article is CSK-IIA, CSK-IIIA and CSK-IVA:
a) The shape and size of CSK-IIA test block shall comply with the provisions in table
23 and figure 14;
b) See Annex O for the shape and size of CSK-IIIA;
c) The shape and size of CSK-IVA test block shall comply with the provisions in
table 24 and figure 15;
d) When requirements for standard sensitivity is met, artificial reflector on the test
block can adopt other arrangement form or add in accordance with testing
demands, and can use equivalent test blocks in other forms.
6.3.3.3 Use principle of test block
6.3.3.3.1 CSK-IA, CSK-IIA, CSK-IIIA and CSK-IVA test blocks are applicable to
ultrasonic testing for welded joint with tested surface curvature radius greater than or
equal to 250 mm.
6.3.3.3.2 CSK-IA, CSK-IIA, CSK-IIIA and CSK-IVA test blocks are applicable to
ultrasonic testing for welded joint with work piece wall thickness of 6 mm to 500 mm,
in which CSK-IIA is applicable to welded joint with work piece wall thickness of 6 mm
to 200 mm, and CSK-IVA is applicable to welded joint with work piece wall thickness
of 200 mm to 500 mm.
6.3.3.3.3 For ultrasonic testing for welded joint with work piece wall thickness of 8 mm
to 120mm, it can also use CSK-IIIA test block (refer to Annex O), but the sensitivity
shall be accordingly adjusted to keep consistent with CSK-IIA test block.
6.3.3.3.4 When testing is performed to welded joint with different base material nominal
thickness, the selection of test block thickness shall be determined by the thicker work
piece, and scanning sensitivity and quality grading shall be determined by the thinner
one.
Table 13 -- Size of CSK-IIA test block Unit: mm
CSK-II A SN
Applicable base
material
nominal
thickness t
Test block
thickness T
Transverse hole
position
Transverse hole
diameter d
CSK-II A1 ≥ 6 ~ 40 45 5, 15, 25, 35 Φ2.0
CSK-II A-2 > 40 ~ 100 110 10, 30, 50, 70, 90 Φ2.0
CSK-II A-3 > 40 ~ 200 210
10, 30, 50, 70,
90, 110, 140,
170, 200
Φ2.0
Note 1: hole diameter deviation is not greater than ±0.02 mm, and other size deviation is not
greater than ±0.05 mm.
Note 2: The test block length shall be determined by the acoustic travel used.
Note 3: if the acoustic feature is the same or similar, the thicker test block can replace the
thinner one.
Note 4: It can add transverse hole quantity within the full thickness range of the test block.
Note 5: Transverse holes with other diameters can be used too, but the sensitivity shall be
equivalent.
Note 6: The perpendicularity deviation of opening hole shall not be greater than 0.1 degree.
Note: the size deviation shall not be greater than ± 0.05 mm.
Figure 13 -- CSK-IA test block
Organic glass
The rest
Through hole
All
a) CSK-IIA-1 test block
b) CSK-IIA-2 test block
c) CSK-IIA-3 test block
Figure 14 -- CSK-IIA test block (recommended)
All
All
Table 24 -- Size of CSK-IVA Unit: mm
CSK-IIA
SN
Applicable
base
material
nominal
thickness t
Test block
thickness T
Test block
length L
Transverse hole
position
Transverse
hole
diameter d
CSK-IVA-1 > 200 ~ 300 310 See note 2
10, 30, 50, 80, 110,
150, 190, 240, 290 Φ6
CSK-IVA-2 > 300 ~ 400 410 See note 2
10, 30, 50, 80, 110,
150, 190, 240, 290,
340, 390
Φ6
CSK-IVA-3 > 400 ~ 500 510 See note 2
10, 30, 50, 80, 110,
150, 190, 240, 290,
340, 390, 440, 490
Φ6
Note 1: hole diameter deviation is not greater than ±0.02 mm, and other size deviation is not
greater than ±0.05 mm.
Note 2: The test block length shall be determined by the acoustic travel used.
Note 3: if the acoustic feature is the same or similar, the thicker test block can replace the
thinner one.
Note 4: It can add transverse hole quantity within the full thickness range of the test block.
Note 5: Transverse holes with other diameters can be used too, but the sensitivity shall be
equivalent.
Note 6: The perpendicularity deviation of opening hole shall not be greater than 0.1 degree.
a) CSK-IVA-1 test block
All
b) CSK-IVA-2 test block
All
c) CSK-IVA-3 test block
Figure 15 -- Schematic diagram of CSK-IVA test block (recommended)
6.3.4 Testing zone
6.3.4.1 Testing zone shall be represented by width of testing zone of welded joint and
thickness of testing zone of welded joint.
6.3.4.2 Width of testing zone of welded joint shall be determined by welding seam
adding welding seam fusion line for 10 mm at both sides. V-shaped groove butt joint
testing zone is shown in figure 16.
6.3.4.3 Thickness of testing zone of butt joint shall be base material nominal thickness
plus excess weld metal of welding seam.
6.3.4.4 Ultrasonic inspection shall cover the entire area. If it cannot fully cover by
increasing the number of test probe or increasing the tested surface (side), it shall
increase auxiliary testing, including other nondestructive testing methods.
All
Note: a refers to width of testing zone of welded joint.
Figure 16 -- Schematic diagram of testing zone
6.3.5 Testing surface preparation
6.3.5.1 Probe moving zone width
6.3.5.1.1 Probe moving zone width shall satisfy to test the whole testing zone, as
shown in figure 17.
Figure 17 -- Schematic diagram of probe moving zone width
6.3.5.1.2 When primary reflection method is used, the probe moving zone width shall
be greater than or equal to 1.125P:
P = 2Kt ……………………………………… (3)
Probe moving zone width
or
P = 2t × tan β …………………………………… (4)
where:
P - crossing distance, mm;
t - base material nominal thickness, mm;
K - tangent value of probe refraction angle;
β - probe refraction angle, (°).
6.3.5.1.3 When direct method is used for testing, probe moving zone width shall be
greater than or equal to 0.75P.
6.3.5.2 The tested surfaces shall be removed from paint, welding spatter, iron, oil dirt
and other foreign matters, lest affect acoustic coupling and defect judgment. The tested
surface shall be smooth. The clearance between tested surface and probe wedge
bottom or protective film shall not be greater than 0.5 mm, and its surface roughness
(value Ra) shall be smaller or equal to 25 μm. The tested surface shall be polished.
The excess weld metal shall be polished parallel to the parent material. Reserve weld
seam with excess weld metal, if the surface of weld seam has bite edge, larger uplift
and depression, it shall be properly ground, and rounded off so as not to affect the test
results evaluation.
6.3.6 Probe refraction angle (value K), nominal frequency
6.3.6.1 Refraction of angle probe (value K), and nominal frequency can be selected in
accordance with provisions in table 25. When condition allowed, it shall try to use probe
with larger refraction angle (value K).
6.3.6.2 When first reflection method is used for testing, the selection of refraction of
angle probe (value K) shall make the interaction angle of main sound beam and bottom
normal opposite to the tested surface between 35 to 70 degree. When two or more
refraction of angle probe (value K) are used for testing, one refraction of angle probe
(value K) shall meet this requirement at least.
Table 25 -- Refraction of angle probe (value K) and nominal frequency
recommended for use
Base material nominal
thickness t/mm
Refraction angle (value K) Nominal frequency/MHz
≥ 6 ~ 25 63o ~ 75o (2.0 ~ 3.0) 4 ~ 5
> 25 ~ 40 56o ~ 68o (1.5 ~ 2.5) 2 ~ 5
> 40 45o ~ 63o (1.0 ~ 2.0) 2 ~ 2.5
6.3.6.3 Nominal frequency of straight probe can be selected in accordance with
provisions in table 25.
Table 26 -- Nominal frequency of straight probe recommended for use
Base material nominal thickness t/mm Nominal frequency/MHz
≥ 6 ~ 40 4 ~ 5
> 40 2 ~ 5
6.3.7 Testing of parent material
For Grade C testing or when necessary, parent material zone passing through by the
angle probe scanning beam shall be tested by the straight probe at first, to detect
whether there are layers or other types of defects to influence probe testing results.
This testing is only recorded, not belongs to acceptance testing of parent materials.
The main point for testing of parent materials are as follows:
a) Scan sensitivity: the secondary bottom wave is adjusted to 100 % of full scale of
fluorescent screen at place where without defects;
b) Any positions where defect signal amplitude exceeds 20 % of full scale of
fluorescent screen shall be marked on the work piece surface, and recorded.
6.3.8 Instrument regulation
6.3.8.1 Incidence point and refraction angle (value K) of angle probe
The measurement of incidence point of angle probe shall generally adopt CSK-IA test
block, and measurement of refraction angle (value K) shall use CSK-IA, CSK-IIA, CSK-
IIIA or CSK-IVA test block.
6.3.8.2 Instrument baseline
Adjustment of instrument baseline shall commonly use CSK-IA test block, and it also
can choose CSK-IIA, CSK-IIIA or CSK-IVA test block according to the thickness of the
work piece.
6.3.8.3 Distance - amplitude curve drawing
Distance - amplitude curve shall be drawn according to actual data of the probe and
instrument on test block. This curve family is composed of assessment curve,
quantitative curve and waste determined line. The space between assessment curve
and quantitative curve (including assessment curve) is Zone I, the space between
quantitative curve and waste determined line (including quantitative curve) is Zone II,
and the space in waste determined line and its above area is Zone III, as shown in
figure 18. If the distance-amplitude curve is drawn on the display screen, the height of
any point on the curve shall not be lower than 20 % of full scale of fluorescent screen
within the testing range.
Figure 18 -- Distance - amplitude curve
6.3.8.4 Sensitivity selection of distance - amplitude curve
6.3.8.4.1 For welded joint with base material nominal thickness of 6 mm to 200 mm,
when angle probe or straight probe are used for testing, sensitivity of distance -
amplitude curve made by CSK-IIA shall be according to provisions in table 27.
Table 27 -- Sensitivity of distance - amplitude curve with angle probe or straight
probe for testing
Test block type
Base material
nominal
thickness t/mm
Assessment
curve
Quantitative
curve and
Waste
determined line
CSK-IIA
≥ 6 ~ 40
> 40 ~ 100
> 100 ~ 200
Φ2 × 40 - 18 dB
Φ2 × 60 - 14 dB
Φ2 × 60 - 10 dB
Φ2 × 40 - 12 dB
Φ2 × 60 - 8 dB
Φ2 × 60 - 4 dB
Φ2 × 40 - 4 dB
Φ2 × 60 + 2 dB
Φ2 × 60 + 6 dB
6.3.8.4.2 For welded joint with base material nominal thickness of 8 mm to 120 mm,
when angle probe is used for testing, sensitivity of distance -amplitude curve made by
CSK-IIIA shall be according to provisions in Annex O.
6.3.8.4.3 For welded joint with base material nominal thickness of 200 mm to 500 mm,
when angle probe or straight probe are used for testing, sensitivity of distance -
amplitude curve shall be according to provisions in table 28.
Table 28 -- Sensitivity of distance - amplitude curve with angle probe or straight
probe for testing
Test block type Base material nominal
Assessment
curve
Quantitative
curve and
Waste
determined line
Amplitude/dB
Rejection line (RL)
Scale line (SL)
Evaluation line (EL)
Distance/mm
thickness t/mm
CSK-IVA ≥ 200 ~ 300 Φ6-13 dB Φ6-7 dB Φ6+3 dB ≥ 300 ~ 500 Φ6-11 dB Φ6-5 dB Φ6+5 dB
6.3.8.4.4 Work piece surface coupling loss and material attenuation shall be the same
as the block, otherwise sound energy transmission loss shall be measured in
accordance with provisions in Annex P, and compensation shall be conducted. The
compensation amount shall be included into distance - amplitude curve.
6.3.8.4.5 Scanning sensitivity shall not be lower than sensitivity of assessment curve.
For this case, the height of assessment curve shall not be lower than 20 % of full scale
of fluorescent screen at place where the acoustic travel is the largest within the testing
range.
6.3.8.4.6 When transverse defect is tested and assessed, sensitivity of each line shall
raise 6 dB respectively.
6.3.9 Scanning method
6.3.9.1 Scanning with angle probe
6.3.9.1.1 When it tested longitudinal defect of welded joint, the angle probe shall be
perpendicular to the welded center line and placed on the testing surface, to make
prionodont scanning, as shown in figure 19. When the scanning probe moved back
and forth, it shall ensure to scan the entire cross section of welded joint. When the
probe is maintained to vertical to the weld seam and move back and forth, it shall make
rotation from right to left with angle of 10 to 15 degree. In order to observe defect
dynamic wave form and distinguish defect signal from pseudo-defect signal, it shall
confirm the location, direction and shape of the defect. It can adopt four kinds of probes
to conduct basic scanning, which are back and forth, right to left, around the corner
and circulation, as shown in figure 20.
Figure 19 -- Prionodont scanning
Figure 20 -- Four basic scanning methods
6.3.9.1.2 When transverse defect of welded joint is tested, it can make angle probe
and center line of welded joint forming parallel scanning to two directions not more
than 10 degree on the edge at both sides of the welded joint, as shown in figure 21. If
the excess weld metal of welded joint is polished, the probe shall make parallel
scanning to two directions on the welded joint and heat influence zone, as shown in
figure 22.
Figure 21 -- Oblique parallel scanning Figure 22 -- Parallel scanning
6.3.9.1.3 For electroslag welded joint, it shall add oblique scanning forming 45degree
of the welding center line.
6.3.9.2 Scanning with straight probe
When scanning with straight probe, it shall ensure that the ultra sound beam can scan
the whole tested zone of welded join.
6.3.10 General rules on ultrasonic testing of butt joint with tested surface curvature
radius less than 250 mm.
6.3.10.1 When curvature work piece is tested, if curvature radius of tested surface: R
≤ W2/4, (W refers to width of probe contact surface, probe width in time of circular seam
testing, and probe length in time of longitudinal seam testing), it shall adopt reference
block with same curvature with the tested surface. The location of reflection hold can
be determined based on reference block. The test block width b shall generally meet:
Back and forth Left and right Around the corner Circulation
where:
b - test block width, mm;
λ - length of ultrasonic wave, mm;
S - sound travel, mm;
Do - effective diameter of sound source, mm.
6.3.10.2 Testing of curvature surface longitudinal butt joint
6.3.10.2.1 Curvature radius of work piece tested surface shall be within the range of
0.9 to 1.1 times of curvature radius of reference block.
6.3.10.2.2 Refraction angle (value K) of the probe shall be selected based on curvature
of work piece and base material nominal thickness and the limitation of geometric
critical angle shall be considered to ensure sound beam can scan the whole welded
joint.
6.3.10.2.3 After the probe contact surface is polished, attention shall be paid to
changes in incidence point and refraction angle (value K) of the probe, and actual
measurement shall be made with curvature reference block.
6.3.10.2.4 Note defect depth indicated on the display screen or actual radial buried
distance between horizontal distance and defects or difference of horizontal distance
arc length, and modify.
6.3.10.2.5 See Annex J for ultrasonic testing method for curvature longitudinal butt
joint.
6.3.10.3 Testing for curvature circular butt joint
6.3.10.3.1 Curvature radius of work piece tested surface shall be within the range of
0.9 to 1.1 times of curvature radius of reference block.
6.3.10.3.2 See Annex K for ultrasonic testing method for curvature circular butt joint.
6.3.11 See Annex L for ultrasonic testing method for connecting pipe and cylinder (or
end socket) fillet joint.
6.3.12 See Annex for ultrasonic testing method for T-shaped welded joint.
6.3.13 Defect quantitative
6.3.13.1 For defect whose amplitude reaches or exceeds assessment curve, it shall
determine its location, amplitude and indicated length etc.
6.3.13.2 Defect amplitude
6.3.13.2.1 Move the probe to obtain the maximum reflection amplitude of defect, and
this is the defect amplitude.
6.3.13.2.2 When probe with different refraction angle (value K) are used to test the
same defect from different tested surface (side), the maximum amplitude obtained is
the defect amplitude.
6.3.13.3 Defect position
Defect position shall be subject to location where the maximum amplitude obtained.
6.3.13.4 Indicated defect length
6.3.13.4.1 When defect reflection wave only has one high point, and is located at Zone
II or above Zone II, -6 dB method shall be used to measure its length.
6.3.13.4.2 When the defect reflection wave peaks are fluctuated with changes, have
more than one high points, and are located at Zone II or above Zone II, the endpoint -
6 dB method shall be used to measure its length.
6.3.13.4.3 When the maximum defect reflection amplitude is located at the Zone I,
move the probe from right to left to make the amplitude dropped to assessment curve,
so that the assessment curve with absolute sensitivity method can be used to measure
the indicated length of defects.
6.3.14 Defect assessment
6.3.14.1 For signals exceeding the assessment curve, attention shall be paid whether
there are crack, incomplete fusion, incomplete penetration and other defects. If there
is any doubt, judgment shall be made by changing the probe refraction angle (value
K), adding tested surface, observing dynamic waveform and in combination of the
structure technology. If it is unable to judge waveform, comprehensive judgment shall
be conducted with help of other testing method.
6.3.14.2 Two adjacent defects along the length direction, when the space between
length directions is shorter than the smaller defect length, and the space between two
defects and vertical direction of defect length is lower than 5 mm, it shall be dealt with
as one defect, and the sum of the length of two defect shall be taken as the indicated
length (the space shall be included into). If the projection of two defects are overlapped
in the length direction, the left and right end space of two defects at the length direction
shall be taken as its indicated length on the projection.
6.4 Ultrasonic testing method for II type welded joint of pressure equipment
6.4.1 Scope
6.4.1.1 This article is applicable to ultrasonic testing method for II type welded joint,
and see table 29 for II type welded joint.
Table 29 -- Applicable scope of ultrasonic testing of II type welded joint Unit: mm
Pressure equipment
type Welded joint type
Base material
nominal
thickness t
Diameter of tested surface
Boiler, pressure
container
Pipe circular butt
joint
≥ 6 ~ 50 Outer diameter ≥ 32 ~ 159
≥ 4 ~ 6 Outer diameter ≥ 32
Pressure pipe Circular butt joint ≥ 6 ~ 50 Outer diameter ≥ 32 ~ 159 ≥ 4 ~ 6 Outer diameter ≥ 32
6.4.1.2 Ultrasonic testing method and quality grading for butt joint (II type welded joint)
of equipment pipe and pressure pipe made by aluminum and aluminum alloy can be
conducted in accordance with this article.
6.4.1.3 This article is not applicable to ultrasonic testing for butt joint of austenite
stainless steel and austenite - ferrite duplex stainless steel pressure pipe.
6.4.2 Reference blocks
6.4.2.1 The reference blocks shall be manufactured in accordance with provisions in
4.2.3.2.
6.4.2.2 The type of reference block used are GS-1, GS-2, GS-3, and GS-4, and the
shape and size shall comply with the provisions in figure 23 and table 30 respectively.
All
Figure 23 -- Shape and size of GS test block
Table 30 -- Curvature radius of test block arc Unit: mm
Test block
model
Curvature
radius of test
block arc, R1
Applicable outer
range of the
pipe
Curvature
radius of test
block arc, R2
Applicable outer
range of the
pipe
GS-1 18 32 ~ 40 22 40 ~ 48
GS-2 26 48 ~ 57 32 57 ~ 72
GS-3 40 72 ~ 90 50 90 ~ 110
GS-4 60 110 ~ 132 72 132 ~ 159
Note: Based on testing requirements, it can add applicable test block with different curvature
and thickness range.
6.4.3 Probe
6.4.3.1 It is recommended to use line focus angle probe and double wafer angle probe,
because its performance can meet testing requirements.
6.4.3.2 The nominal frequency of the probe generally uses 4 MHz to 5 MHz. When the
wall thickness is greater than 15mm, it shall adopt probe with 2 MHz to 2.5 MHz.
6.4.3.3 Refraction angle (value K) of angle probe can be selected in accordance with
provisions in table 31. If necessary, it can also use probes with other refraction angle
(value K).
6.4.3.4 Curvature of probe wedge shall be processed into the shape in conformity with
the outer diameter of connecting pipe. The probe with processed curvature shall
measure the refraction angle (value K) and frontier value, and it is required the first
wave shall at least scan to the root of welded joint.
6.4.4 Testing position and probe moving area
Table 31 -- Selection for refraction angle (value K) of angle probe
Wall thickness of pipe t/mm Refraction angle (value K) of probe Probe frontier/mm
≥ 4 ~ 8 68o ~ 72o (2.5 ~ 3.0) ≤ 6
> 8 ~ 15 63o ~ 68o (2.0 ~ 2.5) ≤ 8
> 15 56o ~ 63o (1.5 ~ 2.0) ≤ 12
6.4.4.1 It generally requires conducting testing from both sides of the welded joint. If it
only can conduct testing from one side of the welded joint due to condition limited, it
shall use two or more kinds of different probes for testing.
6.4.4.2 The probe moving area shall be removed with welding spatter, iron scrap, oil
dirt and other impurities, and the surface roughness Ra ≤ 25 μm. The probe moving
area shall be greater than 1.5P, and the calculation of P shall be based on provisions
in 6.3.5.1.2.
6.4.5 Drawing of distance - amplitude curve
6.4.5.1 It shall accord with table 30 to select reference block corresponding to actual
work piece curvature.
6.4.5.2 Distance - amplitude curve shall be drawn according to actual data of the probe
and instrument on test block. This curve family is composed of assessment curve,
quantitative curve and waste determined line. The space between assessment curve
and quantitative curve (including assessment curve) is Zone I, the space between
quantitative curve and waste determined line (including quantitative curve) is Zone II,
and the space in waste determined line and its above area is Zone III, as shown in
figure 24.
Figure 24 -- Distance - amplitude curve
6.4.5.3 Sensitivity of distance - amplitude curve with different pipe wall thickness shall
be according to provisions in table 32.
Table 32 -- Sensitivity of distance - amplitude curve
Base material
nominal thickness
t/mm
Assessment curve Quantitative curve Waste determined line
≥ 4 ~ 8 Φ2 × 20 - 24 dB Φ2 × 20 - 18 dB Φ2 × 20 - 24 dB
> 8 ~ 15 Φ2 × 20 - 20 dB Φ2 × 20 - 14 dB Φ2 × 20 -8 dB
> 15 Φ2 × 20 - 16 dB Φ2 × 20 - 10 dB Φ2 × 20 -4 dB
6.4.5.4 In time of testing, sound energy transmission loss shall be measured in
accordance with provisions in Annex P, and compensation shall be conducted based
on actual measured results. The compensation amount shall be included into distance
- amplitude curve.
Amplitude/dB
Rejection line (RL)
Scale line (SL)
Evaluation line (EL)
Distance/mm
6.4.5.5 Scanning sensitivity shall not be lower than sensitivity of assessment curve.
6.4.6 Scanning method
Scanning shall be conducted to make both sides of butt joint of the probe vertical to
the welded joint. The probe moving distance back and forth shall meet requirement.
The probe movement from right to left shall make scanning coverage greater than 15 %
of probe width.
6.4.6.2 In order to observe defect dynamic waveform and distinguish defect signal from
pseudo-defect signal, it shall confirm the location, direction and shape of the defect,
and it can adopt scanning method as back and forth and from right to left etc.
6.4.7 Defect quantitative
6.4.7.1 For defects with reflection amplitude locating at Zone I or above Zone I,
measurement shall be conducted to defect position, the maximum reflection amplitude
of the defect and defect indicated length etc.
6.4.7.2 Defect position shall be subject to location where the maximum amplitude
obtained.
6.4.7.3 The measurement method of the maximum reflection amplitude of the defect
is to move the probe to location where the defects appear the maximum reflection
wave signals, so as to measure the wave amplitude, and determine its regions in the
distance - amplitude curve.
6.4.7.4 Measurement of defect indicated length shall be carried out based on the
following method:
6.4.7.4.1 When defect reflection wave only has one high point, and is located at Zone
II or above Zone II, 6dB method shall be used to measure its length.
6.4.7.4.2 When the defect reflection wave peaks are fluctuated with changes, have
more than one high points, and are located at Zone II or above Zone II, then, the
endpoint -6 dB method shall be used to measure its length.
6.4.7.4.3 When the maximum defect reflection amplitude is located at the Zone I, move
the probe from right to left to make the amplitude dropped to assessment curve, so
that the assessment curve with absolute sensitivity method can be used to measure
the indicated length of defects.
6.4.7.4.4 The actual indicated length of the defect (l) shall be calculated in accordance
with formula (6) (it is applicable to smaller pipe diameter but larger wall thickness):
l = L × (R - H)/R …………………………………… (6)
where:
L - measured defect indicated length, mm;
R - outer diameter of the pipe, mm;
H - defect depth, mm.
6.4.8 Defect assessment
6.4.8.1 For signals exceeding the assessment curve, attention shall be paid whether
there are crack, incomplete fusion, incomplete penetration and other defects. If there
is any doubt, comprehensive judgment shall be made by changing the probe refraction
angle (value K), observing dynamic waveform and combining the welding technology
etc.
6.4.8.2 When two adjacent defects are on a same straight line, when the space is
shorter than the smaller defect length, it shall be dealt with as one defect, and the sum
of the length of two defect shall be taken as the indicated length of a single defect (the
space shall be included into defect length).
6.5 Quality grading
6.5.1 Quality grading for welded joint of boiler and pressure container
6.5.1.1 Welded joint of boiler and pressure container includes cylinder (or end socket)
butt joint, connecting pipe and cylinder (or end socket) fillet joint and T-shaped welded
joint.
6.5.1.2 Welded joint of boiler and pressure container is not allowed to have crack,
incomplete fusion and incomplete penetration etc.
6.5.1.3 Defect below the assessment curve shall be rated as Grade I.
6.5.1.4 Quality grading for welded joint of boiler and pressure container shall be carried
out in accordance with table 33.
Table 33 -- Quality grading for welded joint of boiler and pressure container
Unit: mm
Grade
Base
material
nominal
thickness
Located area
of reflection
amplitude
Allowed indicated length of a
single defect
The maximum
allowable value of
several defect
accumulated length
/L’
I ≥ 6 ~ 100 I ≤ 50 — >100 ≤ 75 —
≥ 6 ~ 100
II
≤ t/3, the minimum value can
be 10, but the maximum value
not exceeding 30.
L’ not exceeding t
within any 9t
welding seam
length range. > 100 ≤ t/3, the maximum value not exceeding 50.
II
≥ 6 ~ 100 I ≤ 60 — > 100 ≤ 90 —
≥ 6 ~ 100
II
≤ 2t/3, the minimum value can
be 12, but the maximum value
not exceeding 40.
L’ not exceeding t
within any 4.5t
welding seam
length range. > 100 ≤ 2t/3, the maximum value not exceeding 75.
III ≥ 6
II Exceeding Grade II
III All defects (any defect indicated length)
I Exceeding Grade II —
Note 1: when welding seam length is shorter than 9t (Grade I) or 4.5t (Grade II), it can be
converted based on proportion. When allowable value of several defect accumulated value
after conversion is less than the single defect indicated length allowed in this Grade, the
allowed single defect indicated length shall be taken as the defect accumulative length
allowable value.
Note 2: With the measurement method specified in 6.3.13.4, it shall make the sound beam
vertical to major direction of the defect and defect length is measured by moving the probe.
6.5.2 Quality grading for pipe circular or longitudinal welded joint of boiler and pressure
container
6.5.2.1 Pipe circular or longitudinal welded joint of boiler and pressure container is not
allowed to have crack, incomplete fusion and incomplete penetration etc.
6.5.2.2 Defect below the assessment curve shall be rated as Grade I.
6.5.2.3 Quality grading for pipe circular or longitudinal welded joint of boiler and
pressure container shall be carried out in accordance with table 34.
Table 34 -- Quality grading for pipe circular or longitudinal welded joint of
boiler and pressure container
Grade
Located area of
reflection
amplitude
Allowed indicated length of a single defect
I ≤ 40
II ≤ t/3, the minimum value can be 5, but the maximum value not exceeding 30.
II I ≤ 60 II ≤ 2t/3, the minimum value can be 10, but the maximum
value not exceeding 40.
III
II Exceeding Grade II
III All defects
I Exceeding Grade II
Note: When the thickness of parent material at both sides of butt joint is different, the base
material nominal thickness shall take the thickness value at thinner side.
6.5.3 Quality grading for circular or longitudinal welded joint of pressure pipe
6.5.3.1 Circular welded joint of pressure pipe is not allowed to have crack and
incomplete fusion etch.
6.5.3.2 Longitudinal welded joint of pressure pipe is not allowed to have crack,
incomplete fusion and incomplete penetration etc.
6.5.3.3 Defect below the assessment curve shall be rated as Grade I.
6.5.3.4 Quality grading for circular or longitudinal welded joint of pressure pipe shall
be carried out in accordance with table 35.
Table 35 -- Quality grading for pipe circular or longitudinal welded joint of
pressure pipe
Grade of
welded
joint
Internal defect of welded joint Incomplete penetration defect at single welding root of circular welded joint
Located area
of reflection
amplitude
Allowed indicated length
of a single defect/mm
Allowed
indicated
length/mm
Allowed accumulated
length/mm
I ≤ 40
≤ t/3, the
minimum value
can be 8
The length is shorter
than or equal to 10 % of
perimeter of weld seam,
and shorter than 30.
II
≤ t/3, the minimum value
can be 8, but the
maximum value not
exceeding 30.
II
I ≤ 60
≤ 2t/3, the
minimum value
can be 10
The length is shorter
than or equal to 15 % of
perimeter of weld seam,
and shorter than 40.
II
≤ 2t/3, the minimum
value can be 10, but the
maximum value not
exceeding 40.
III
II Exceeding Grade II Exceeding
Grade II Exceeding Grade II III All defects I Exceeding Grade II
Note 1: Within 10 mm of circular welded joint, it shall be rated as Grade III if silver defect and
incomplete penetration exist together.
Note 2: When allowable value of defect accumulated value is less than the single defect
indicated length allowed in this Grade, the allowed single defect indicated length shall prevail.
Note 3: When the thickness of parent material at both sides of butt joint is different, the base
material nominal thickness shall take the thickness value at thinner side.
7 Ultrasonic measuring methods for thickness of
pressure equipment
7.1 Scope
This article is applicable to ultrasonic measurement of thickness of boiler, pressure
container cylinder, end socket, connecting pipe and surfacing layer, and it is also
suitable for ultrasonic measurement of thickness of pressure pipe.
7.2 Sound velocity of several major materials
See table 36 for sound velocity of several major materials. When use, it shall measure
the actual sound velocity of the materials if necessary.
Table 36 -- Longitudinal wave sound velocity of several major materials Unit: mm
Material name Aluminum Steel Stainless steel Cooper Zirconium Titanium Nickel
Longitudinal
wave sound
velocity
6260 5900 5790 4700 4310 6240 5630
7.3 Measuring instrument
7.3.1 Thickness measuring instrument includes ultrasonic detector, scan displayed
digital thickness meter with A and digital thickness meter. All these instruments shall
be selected according to the thickness range, surface condition, material and
measurement accuracy of tested work piece. Ultrasonic detector is generally suitable
for thickness measurement of pressure equipment with wall thickness greater than 200
mm, and the measurement accuracy is usually ±1 mm; scan displayed digital thickness
meter with A and digital thickness meter are generally suitable for thickness
measurement of pressure equipment with wall thickness less than 200 mm, and the
measurement accuracy is usually ± (0.5 %t + 0.05) mm.
7.3.2 Ultrasonic detector show time - amplitude signal in A scanning way, to measure
thickness through reading distance between the initial pulse and the first bottom wave,
or measure the thickness according to distance difference among several bottom
echoes on A scanning display baseline.
7.3.3 Scan displayed digital thickness meter with A is a combination of A scanning
display ultrasonic detector and additional circuit of digital display thickness value.
Scanning display meter with A can check effectiveness of the measurement, and can
display changes of measurement situation, such as defects or discontinuities inside
the work piece.
7.3.4 Digital thickness meter is to transfer the sound velocity or time between the initial
pulse and the first bottom echo or several bottom echoes into figures and display on
the instrument.
7.4 Probe
7.4.1 Ultrasonic thickness meter usually adopts direct contact type of single wafer
straight probe, and it can also use single wafer straight probe or double single wafer
straight probe with deferred block.
7.4.2 Wall thickness measurement for sample with high temperature (greater than or
equal to 60 centigrade degree) or low temperature (below 20 centigrade degree) shall
use special probe.
7.5 Calibration block
The basic requirement and size of calibration block are shown in figure 25, and it can
also use other test blocks to calibrate the instrument under condition of meeting
measurement accuracy.
7.6 Coupling agent
7.6.1 Coupling agent shall comply with provisions 4.2.4.
7.6.2 When it is used in high temperature circumstance, it should choose proper high-
temperature coupling agent.
7.7 Instrument calibration
7.7.1 Instrument calibration shall generally be conducted on a test block which has
same or similar sound velocity with the tested material.
7.7.2 Calibration of digital thickness meter
a) Use the ladder block, calibration shall be conducted on test block with thickness
close to the maximum value of tested thickness and the minimum value of tested
thickness (or 1/2 of the maximum value of tested thickness);
b) Place the probe on the thicker test block, and adjust the knob of “sound velocity
calibration” to make the thickness meter displayed reading close to the known
value;
c) Place the probe on the thinner test block, and adjust the knob of “zero position
calibration” to make the thickness meter displayed reading close to the known
value;
d) Adjust repeatedly, to make higher and lower ends of the measuring range acquire
correct readings;
e) If the material sound velocity is known, it can preset the sound velocity value,
and then on the test block attached with the instrument, adjust the knob of “zero
position calibration” to make the instrument displaying thickness of the test block
7.7.3 Calibration of ultrasonic detector
a) The same as 7.7.2 a);
b) Place the probe on the thicker test block, and adjust the knob of “depth range”
on the detector until the bottom echo appears on the corresponding scale;
c) Place the probe on the thinner test block, and adjust the knob of “scanning delay”
until the bottom echo appears on the corresponding scale;
d) Adjust repeatedly until bottom echoes appear on the correct scale position on the
thick and thin test block;
e) When the thickness of tested work piece is rather thicker, it shall adjust the
instrument to make several bottom wave range of test block exceeding base
material nominal thickness value, and calibrate the instrument with several
bottom waves.
Figure 25 -- Ultrasonic thickness measuring test block
7.7.4 Calibration of scan displayed digital thickness meter with A
The scan displayed digital thickness meter with A can be calibrated in accordance with
7.7.2 or 7.7.3.
7.8 Factor to influence measurement accuracy
7.8.1 Coupling agent
It shall select coupling agent without bubbles and with suitable viscosity in accordance
with the surface state of work piece and acoustic impedance. For work piece with rough
surface, it shall select thicker coupling agent, and appropriately increase the amount
of coupling agent.
All
7.8.2 Contact surface of probe and work piece
a) The measurement surface shall be removed with floating rust, scale or partial
detached coating, and performed with proper grinding if necessary;
b) When probe is contacting with the work piece, a certain amount of pressure shall
be added on the probe (20 N ~ 30 N) to ensure good coupling between the probe
and the work piece, and it shall also eliminate redundant coupling agent to make
the contact surface form a very thin coupling layer.
7.8.3 Work piece defect
When there are small inclusions or stratified defects existed in measuring area, the
thickness data will be abnormal. For this case, if necessary, ultrasonic detector shall
be used to detect abnormal area and thickness measurement.
7.9 Instruments review
7.9.1 In case of the following circumstance, it shall review instrument:
a) Thickness is measured for more than l hour continuously;
b) When probe or probe line are replaced;
c) When the type of measurement material is changed;
d) When there are obvious changes in surface temperature of work piece (the
changes volume exceeds ±14 centigrade degree);
e) When there is a doubt of measurement value;
f) When the measurement is over.
7.9.2 If the review reading deviation exceeds allowable error of the instrument, review
shall be conducted to all measurement data when measurement started or since
review last time.
7.10 Ultrasonic measurement of thickness of austenite stainless steel, nickel
alloy and welding cladding layer
The thickness of welding cladding layer is generally measured by using single wafer
straight probe from the base material side, or measured by using double wafer straight
probe from welding cladding layer side. Measurement can also be carried out by using
other effective methods.
7.10.2 Instrument and probe
7.10.2.1 Thickness measuring meter is generally type A pulse reflection ultrasonic
detector.
7.10.2.2 Double wafer probe
Sound beam of double wafer straight probe shall be selected in accordance with the
thickness of tested welding cladding layer, and it shall ensure that sound isolation effect
between two wafers are good.
7.10.2.3 Single wafer single probe
It shall generally adopt narrow pulse probe, and the nominal frequency is 4 MHz to 5
MHz.
7.10.3 Selection of tested surface
7.10.3.1 When measurement is made to thickness of welding cladding layer with
manually welding, it shall measure from the base material side on principle. If the
manual welding cladding layer allowed machining or other methods to make surface
processing, it can also measure from the welding cladding layer side.
7.10.3.2 When measurement is made to thickness of welding cladding layer with
polarity, it shall either measure from the base material side on principle, or measure
from the welding cladding layer side. When measurement is made from the welding
cladding layer, it shall ensure smooth tested surface as much as possible.
7.10.4 Reference blocks
7.10.4.1 Measurement from welding cladding layer side can use test block as shown
in figure 26.
7.10.4.2 Measurement from base material side can use test block as shown in figure
27.
Figure 26 -- Test block used for thickness measurement from welding cladding
Stainless steel welding cladding layer
Base material
layer side
Note: t refers to thickness of base material.
Figure 27 -- Test block used for thickness measurement from base material
side
7.10.5 Thickness measurement of welding cladding layer
7.10.5.1 When measurement is conducted at welding cladding layer with double wafer
straight probe:
a) On the test block with same or similar acoustic features as base material, adjust
instrument level linear and scanning range;
b) Use test block as shown in figure 26, place the probe at appropriate place on
each step, adjust instrument increment to make welding cladding layer of test
block and echo amplitude in base material interface to be 50 % of full scale of
fluorescent screen, read the displayed value of each thickness of welding
cladding layer at this moment, and compare with actual thickness of welding
cladding layer on the test block;
c) Place the double wafer probe on the welding cladding layer surface of the work
piece, adjust instrument increment to make welding cladding layer of test block
and echo amplitude in base material interface to be 50 % of full scale of
fluorescent screen, read the displayed value of base material nominal thickness
of welding cladding layer at this moment;
d) Modify the displayed value of base material nominal thickness of welding
cladding layer in accordance with compared results in b), then obtain the base
material nominal thickness of welding cladding layer.
7.10.5.2 When measurement is conducted at base material side with single wafer
straight probe:
Welding cladding layer
Base material
a) On the test block with same or similar acoustic features as base material, adjust
instrument level linear and scanning range;
b) Use test block as shown in figure 27, place the probe to center of each step on
the base material as much as possible, adjust instrument increment to make
base material of test block and echo amplitude in welding cladding layer interface
to be 50 % of full scale of fluorescent screen, read the displayed value of each
thickness of base material and corresponding displayed value of bottom wave at
this moment, and compare these two difference values with actual thickness of
welding cladding layer on the test block one by one;
c) Place the double wafer probe on the base material surface of the work piece,
adjust instrument increment to make welding cladding layer of test block and
echo amplitude in base material interface to be 50 % of full scale of fluorescent
screen, and read the displayed value of base material nominal thickness of base
material at this moment. And the difference value between these two is displayed
value of the base material nominal thickness of welding cladding layer.
d) Modify the displayed value of base material nominal thickness of welding
cladding layer in accordance with compared results in b), then obtain the base
material nominal thickness of welding cladding layer.
8 Ultrasonic testing methods of in-service pressure
equipment
8.1 Scope
This section is applicable to the ultrasonic testing methods of in-service pressure
equipment.
8.2 Ultrasonic testing methods of pressure parts of in-service pressure
equipment
8.2.1 Ultrasonic testing technological documents of pressure parts of in-service
pressure equipment
8.2.1.1 Ultrasonic testing technological documents of pressure parts of in-service
pressure equipment shall meet the requirements as specified in 4.3.
8.2.1.2 Ultrasonic testing technological procedures of pressure parts of in-service
pressure equipment shall generally include the related factors listed in Table 1, 2 and
37.
Table 37 -- Factors relating to technological procedures of ultrasonic testing of
pressure parts of in-service pressure equipment
Equipment use conditions (temperature, pressure, medium, working condition, etc.)
Base material surface conditions (corrosion, etc.)
Analysis results of materials failure mode or risk assessment (RBI) (if any)
Note: Pressure parts mean such parts as boiler drum, header, down-comer, water wall tube,
boiler end, manhole, etc. of the boiler body, shell, end (end cap), expansion joint and
equipment flange of the pressure vessel body, spherical plate of the spherical tank, tube
plate and heat exchange tube of the heat exchanger, main stud, joint pipe and pipe flange of
M36 and above equipment, as well as pipes and piping elements of the pressure piping, etc.
8.2.2 Main points of ultrasonic testing of pressure parts of in-service pressure
equipment
8.2.2.1 During the ultrasonic testing of pressure parts of in-service pressure equipment,
the main testing methods shall comply with relevant provisions of section 5.
8.2.2.2 During the ultrasonic testing of pressure parts of in-service pressure equipment,
the testing methods shall be determined according to equipment materials,
manufacturing technical conditions, use conditions (temperature, pressure, medium,
working condition, etc.), analysis results of materials failure mode or risk assessment
(RBI), as well as relevant technical specification, etc.
8.2.2.3 Recommendations for ultrasonic testing methods are given according to the
analysis results of materials failure mode or risk assessment (RBI) as well as the
possibility of defect generation, see Table 38.
8.2.2.4 The ultrasonic testing methods for cladding steel sheet of in-service pressure
equipment shall be conducted according to the provisions specified in 5.4. Attention
shall be paid, during the testing, to the interface between the base material and the
clad plate to see whether there is any disconnection or extension of disconnection.
8.2.2.5 For the ultrasonic testing of in-service bolts or studs, in addition to relevant
provisions specified in 5.6, testing shall also be conducted according to whether there
is any crack at the thread roots, main testing contents listed as follows:
a) Testing shall be conducted by using an angle probe of longitudinal wave at the
bolt end or the stud end, longitudinal wave refraction angle of the angle probe is
generally 2° ~ 8.5°, and nominal frequency is 4 MHz ~ 5 MHz. General testing
by using an angle probe of longitudinal wave is applicable to the testing of no-
bore bolts;
b) Axial testing shall be conducted by using an angle probe of transverse wave with
refraction angle of 45° ~ 56° (K1 ~ K1.5) and nominal frequency of 2 MHz ~ 5
MHz at the unthreaded part of the bolt or stud.
c) The comparative samples of the testing by using an angle probe of longitudinal
wave and the axial testing by using an angle probe of transverse wave shall be
made by bolts or studs with the same or similar material, pattern and
specification as the base materials tested. Artificial reflector (cutting groove) shall
be positioned at the maximum detecting sonic path distance and perpendicular
to the axis of the bolt or stud, and the distance between the cutting groove and
the ends of the bolt shall not be less than the diameter of the bolt. The shape
and size of the artificial reflector are shown in Figure 28. You can also adjust the
bolt’s screwed reflected wave amplitude to a reference wave height, and take it
as the scanning sensitivity;
d) During the ultrasonic testing of in-service bolt or stud, if flaw echo higher than the
cutting groove’s echo amplitude appears at the thread roots, an aided testing
shall be conducted by using other surface nondestructive testing methods to
judge whether there is any flaw that may affect the use.
Table 38 -- Recommendation form of ultrasonic testing methods
Damage
mode
Damage
mechanism
Materials vulnerable
to corrosion or
failure
Possible flaw Ultrasonic testing methods
Environmental
cracking Corrosion fatigue
Almost all metals
and alloys
Scar, hollow, flaw,
node, etc. on the
surface of the
material
Angle probe
testing, etc.
Environmental
cracking Thermal fatigue All metal materials
Metal component
cracking in
repeated thermal
cycles
Angle probe
testing, etc.
Environmental
cracking
High temperature
hydrogen
corrosion
Carbon steel, low
alloy steel, Cr-Mo
steel, stainless steel,
etc.
Cracking of parent
metal
Angle probe
testing, etc.
Environmental
cracking Caustic cracking
Carbon steel, low
alloy steel and
austenitic stainless
steel (including dual-
phase steel)
Cracking of parent
metal connected
with welding seam
Angle probe
testing, etc.
Environmental
cracking
Wet hydrogen
sulfide damage
(bubbling/
hydrogen
induced cracking/
SOHIC/ sulfide
stress corrosion
cracking)
Carbon steel and
low alloy steel
Bubbling or
cracking of parent
metal
Angle probe
testing and
straight probe
testing
Corroded
thinning
Carbon dioxide
corrosion
Carbon steel and
low alloy steel
General corrosion
or pitting corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Corroded
thinning Caustic corrosion
Carbon steel, low
alloy steel and
austenitic stainless
steel (including dual-
phase steel)
Local corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Corroded
thinning Amine corrosion Carbon steel
General corrosion
or local corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Corroded
thinning
Acidic water
corrosion Carbon steel Local corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Corroded
thinning
Corrosion by
hydrochloric acid
All common
construction
materials
General corrosion
or local corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Corroded
thinning
Corrosion by high
temperature
hydrogen/
hydrogen sulfide
By sequence of
increased corrosion
resistance: carbon
steel, low alloy steel,
ferritic stainless steel
and austenitic
stainless steel
(including dual-
General corrosion
Straight probe
testing, ultrasonic
thickness
measurement,
etc.
phase steel)
Corroded
thinning
Corrosion by high
temperature
sulfur/naphthenic
acid
Carbon steel, low
alloy steel, austenitic
stainless steel
(including dual-
phase steel), ferritic
stainless steel and
nickel base alloy
Local corrosion or
pitting corrosion
Angle probe
testing, straight
probe testing,
ultrasonic
thickness
measurement,
etc.
Explanation:
r - inner radius of thread, mm;
L - length of artificial groove, mm;
b - depth of artificial groove, mm.
When the groove is cut at the thread root, the cutting shall follow the helix angle of the
thread, and at this moment b refers to the depth below of the thread root.
Figure 28 -- Artificial Groove
8.3 Ultrasonic thickness measurement of in-service pressure equipment
8.3.1 The ultrasonic thickness measurement of in-service pressure equipment shall
comply with the provisions specified in section 7.
8.3.2 Selection of measurement instruments
8.3.2.1 For uniform corrosion, measurement can generally be conducted with digital
thickness gauge. But if the surface corrosion is serious or the surface coating is thick,
thickness measurement shall be conducted with ultrasonic testing instrument.
8.3.2.2 When the minimum wall thickness needs to be measured in the given areas,
we shall generally use an ultrasonic testing instrument to conduct scanning.
8.3.2.3 For non-uniform corrosion such as pitting corrosion, etc., we shall generally
Artificial groove
use an ultrasonic testing instrument to conduct thickness measurement.
8.3.3 Selection of probe
8.3.3.1 Probe shall be selected according to instrument type, base material thickness,
surface conditions, etc.
8.3.3.2 The probe of digital thickness gauge is generally used together with the gauge.
The probe of ultrasonic testing instrument shall be selected according to the following
conditions:
a) The nominal frequency of the probe selected shall be such as to make the
thickness of the base material to be measured be at least more than 1.5 times
of the wavelength of sound;
b) When the thickness of the base material measured is equal to or larger than 10
mm, we generally use single-crystal straight probe to conduct thickness
measurement; when the thickness of the base material measured is less than 10
mm, we can use double-crystal straight probe to conduct thickness
measurement;
c) For thickness measurement of cambered base material, we shall choose a probe
with small-size crystal plate.
8.4 Ultrasonic testing for welding joints of in-service pressure equipment
8.4.1 Scope
This article is applicable to the ultrasonic testing for welding joints of in-service steel
pressure equipment. The ultrasonic testing for welding joints of in-service nonferrous-
metal pressure equipment shall be conducted according to this article.
8.4.2 Ultrasonic testing technological documents of welding joints of in-service
pressure equipment
8.4.2.1 Ultrasonic testing technological documents of welding joints shall meet the
requirements specified in 4.3.
8.4.2.2 Ultrasonic testing technological procedures of welding joints of pressure
equipment shall generally include the related factors listed in Table 1, 21 and 39.
Table 39 -- Factors relating to technological procedures of ultrasonic testing of
pressure parts of in-service pressure equipment
S/N Related factors
1 Equipment use conditions (temperature, pressure, medium, working conditions, etc.)
2 Analysis results of welding joint failure modes or risk assessment (RBI) (if any)
8.4.3 Main points of ultrasonic testing of welding joints of in-service pressure
equipment
8.4.3.1 During the ultrasonic testing of welding joints of in-service pressure equipment,
the testing methods shall comply with relevant requirements of 6.3 or 6.4, and the
testing shall be conducted, as far as possible, according to the required level of the
original manufacturing and testing technology.
8.4.3.2 During the ultrasonic testing of welding joints of in-service pressure equipment,
the testing position and proportion shall be determined according to equipment
materials, manufacturing technical conditions, use conditions (temperature, pressure,
medium, working condition, etc.), analysis results of materials failure mode or risk
assessment (RBI), as well as relevant technical specification, etc.
8.4.3.3 Recommendations for ultrasonic testing methods are given according to the
analysis results of welding joint failure mode or risk assessment (RBI) as well as the
possibility of defect generation, see Table 40.
Table 40 -- Recommendation form of ultrasonic testing methods
Damage
mode
Damage
mechanism
Materials
vulnerable to
corrosion or failure
Possible flaw
Ultrasonic
testing
methods
Environmental
cracking
Corrosion by
high
temperature
hydrogen
Carbon steel, low
alloy steel, Cr-Mo
steel, stainless
steel, etc.
Weld cracking
Transverse
wave angle
probe testing,
etc.
Environmental
cracking
Caustic
cracking
Carbon steel, low
alloy steel and
austenitic stainless
steel (including
dual-phase steel)
Cracking of
parent metal
connected with
welding seam,
weld cracking or
heat-affected
zone crack
Transverse or
longitudinal
wave angle
probe, etc.
Environmental
cracking
Chloride
stress
corrosion
cracking
Austenitic stainless
steel (including
dual-phase steel),
nickel base alloy,
etc.
Weld cracking or
heat-affected
zone crack
Transverse or
longitudinal
wave angle
probe, etc.
Environmental
cracking
Polythionic
acid stress
corrosion
cracking
Austenitic stainless
steel (including
dual-phase steel),
hastelloy alloy,
nickel base alloy,
etc.
Weld cracking or
heat-affected
zone crack
Transverse or
longitudinal
wave angle
probe, etc.
Environmental
cracking
Amine stress
corrosion
cracking
Carbon steel and
low alloy steel
Weld cracking or
heat-affected
zone crack
Transverse
wave angle
probe testing,
etc.
Environmental
cracking
Wet hydrogen
sulfide
damage
(bubbling/
hydrogen
induced
cracking/
SOHIC/
sulfide stress
corrosion
cracking)
Carbon steel and
low alloy steel
Weld cracking or
heat-affected
zone crack
Transverse
wave angle
probe testing,
etc.
Environmental
cracking
Carbonate
stress
corrosion
cracking
Carbon steel and
low alloy steel
Cracking at weld
zone without
eliminating stress
or cracking at
cold-working
zone
Transverse
wave angle
probe testing,
etc.
Environmental
cracking
Corrosion
fatigue
Almost all metals
and alloys Weld cracking
Transverse or
longitudinal
wave angle
probe, etc.
Environmental
cracking
Thermal
fatigue All metal materials
Metal component
cracking in
repeated thermal
cycles
Transverse or
longitudinal
wave angle
probe, etc.
Environmental
cracking
Reheat
cracking
Low alloy steel,
austenitic stainless
steel (including
dual-phase steel),
as well as nickel
base alloy such as
800H, etc.
Cracking at
strong
constrained
zones, including
connecting pipe
weld and thick-
walled pipe
Transverse or
longitudinal
wave angle
probe, etc.
8.4.3.4 Attention shall be paid, during the ultrasonic testing of stainless steel welding
overlay of in-service pressure equipment, to the interface between the base material
and the welding overlay to see whether there is any extension of disconnection
(stripping).
8.4.4 Flaw quantification
During the testing, we should conduct the quantitative for flaws on or above the
evaluating line of the reflected wave amplitude; besides the determination of flaw
position, wave amplitude and indicating length according to 6.3.13 or 6.4.7, we should
also determine the through thickness dimension of the flaw and estimate, as much as
possible, the flaw types (plane, point and volume types) or nature of the flaw.
8.4.5 Determination of the through thickness dimension of the flaw
8.4.5.1 For flaws all belonging to wave pattern I (see Annex Q for the pattern
recognition) in the two directions (length direction × height (depth) direction), namely
point type flaws, the through thickness dimension of the flaw can be determined by
adopting the AVG method or the comparative method against the artificial reflector
dynamic echo waveform of the test specimen (CSK-III A).
8.4.5.2 For flaws belonging to wave pattern II (see Annex Q for the pattern recognition)
in the length direction and flaws belonging to wave pattern I in the height (depth)
direction, namely linear flaws, the through thickness dimension of the flaw can be
determined by adopting the AVG method or the comparative method against the
artificial reflector dynamic echo waveform of the test specimen (CSK-II A or CSK-IV A).
8.4.5.3 For flaws belonging to wave pattern II, IIIa or IIIb (see Annex Q for the pattern
recognition) in both length and height (depth) direction, the through thickness
dimension of the flaw can be determined by adopting the endpoint diffraction wave
method or the end maximum echo method (see Annex R or Annex S for the
determination methods); you can also adopt the -6dB method, see Annex T for the
determination method.
8.4.5.4 Intensive flaws with echo waveform belonging to pattern IV (see Annex Q for
pattern recognition)
8.4.5.4.1 If in the envelope curve of type-A flaw scanning echo, the peak of each
reflection echo cannot be identified in the scanning line of the display, then they shall
be deemed as a single flaw, and the dimension in the height direction can be
determined by adopting the endpoint diffraction wave method or the end maximum
echo method. If the endpoint diffraction wave or the end maximum echo cannot be
determined, the -6 dB method can be adopted.
8.4.5.4.2 If in the envelope curve of type-A flaw scanning echo, the peak of each
reflection echo can be identified in the scanning line of the display, then the through
thickness dimension of each flaw can be determined respectively according to 8.4.5.1
~ 8.4.5.3.
8.4.5.5 The through thickness dimension of the flaw can also be determined by other
nondestructive testing methods, such as radiographic testing, ultrasonic time of flight
diffraction, etc.
8.4.6 Determination of flaw types
8.4.6.1 Main factors for determination of flaw types
8.4.6.1.1 The determination of flaw types shall mainly adopt welding methods
(including welding technology, base material structure, groove type), flaw position,
indicating length, through thickness dimension of the flaw, flaw amplitude, flaw
directivity, as well as flaw static and dynamic waveform. Usually, we should determine
whether they are point, line (strip included slag, strip blistering, etc.) or plane type flaws
(crack, incomplete fusion, etc.).
8.4.6.1.2 For flaws hard to be determined by adopting ultrasonic testing method, we
should increase radiographic testing or other testing, so as to make a further
comprehensive judgment.
8.4.6.2 Methods for determination of flaw types (steps)
8.4.6.2.1 Basic principle for determination of flaw types
8.4.6.2.1.1 Determination of flaw types shall be conducted according to the following
sequence:
a) Flaw amplitude;
b) Flaw directivity (directionality);
c) Static waveform;
d) Dynamic waveform.
8.4.6.2.1.2 Determination of flaw types should be conducted with the same probe as
used in practical testing.
8.4.6.2.2 Step 1 for determination of flaw types - flaw amplitude
a) When the flaw amplitude is lower than the evaluating line, flaw classification does
not need to be conducted;
b) When the flaw amplitude is 6 dB higher than the rejection line (RL) and the
indicating length is equal to or larger than 10 mm, the flaws can be classified
according to the plane type.
8.4.6.2.3 Step 2 for determination of flaw types - flaw directivity (directionality)
8.4.6.2.3.1 Requirements for the length of flaw
When classification of flaws is conducted according to step 2, the indicating length of
the flaw shall:
a) When the base material thickness 6 mm ≤ t ≤ 15 mm, the indicating length of the
flaw shall be equal to or larger than t;
b) When the base material thickness t > 15 mm, the indicating length of the flaw
shall be equal to or larger than t/2 or 15 mm (which is larger).
8.4.6.2.3.2 Application conditions of step 2:
a) The flaw echo shall belong to the same flaw reflector;
b) When different probes are used, the comparison of flaw amplitudes shall be
conducted at the highest position (Hmax) among the highest flaw echoes. Besides,
the smallest among the highest flaw echoes tested by each probe shall be the
minimum amplitude, Hmin;
c) When using straight probe and angle probe to conduct comparison of reflected
wave amplitude, we should choose the probe with such nominal frequency as
make the wavelength transmitting in the base material be similar;
d) When two or more angle probes with different refraction angles (value K) are
used, the refraction angle difference among the probes shall not be less than 10°;
e) The attenuation correction when one acoustic beam gets through the weld metal
and another acoustic beam only gets through the parent metal shall be taken
into consideration.
8.4.6.2.3.3 Determination of flaw directivity (directionality)
It can be considered that the flaw has directivity when all the following conditions are
satisfied:
a) The maximum reflected wave amplitude, Hmax, is on or above the scale line (SL);
b) When angle probes with different refraction angles (value K) are used, the
difference between the maximum reflected wave amplitude Hmax and the
minimum reflected wave amplitude Hmin shall be equal to or larger than 9 dB; or
when one angle probe and one straight probe are used during the testing, the
different shall be equal to or larger than 15 dB.
8.4.6.2.4 Step 3 for determination of flaw types - static waveform
8.4.6.2.4.1 Flaw static waveform means the waveform compared with that of cross-
bore reflection waveform of test specimen CSK-II A or CSK-IV A.
8.4.6.2.4.2 At least one probe shall be used, in two directions which are perpendicular
to each other, to detect flaws.
8.4.6.2.4.3 If the flaws have single, sharp and smooth static waveform, they can be
classified according to non-planar type; otherwise, determination of flaw types shall be
conducted according to step 4.
8.4.6.2.5 Step 4 for determination of flaw types - dynamic waveform
8.4.6.2.5.1 Flaw dynamic waveform means the echo envelope curve obtained by
moving the probe in the direction perpendicular to the flaw’s length direction, and we
shall observe the changes of the waveform.
8.4.6.2.5.2 Flaw dynamic waveform can be divided into five patterns, see Annex Q for
more detail:
a) Wave pattern I: point-type reflector;
b) Wave pattern II: smooth-plane reflector;
c) Wave pattern IIIa: normal-incidence rough-plane reflector;
d) Wave pattern IIIb: oblique-incidence rough-plane reflector;
e) Wave pattern IV: Intensive reflector.
8.4.6.2.6 Determination of flaw types can also be conducted by other nondestructive
testing methods, such as radiographic testing, ultrasonic time of flight diffraction, etc.
8.4.6.3 The flaws detected during the ultrasonic testing shall be verified by comparing
them with the original materials relating to the manufacturing or installation or the
testing results of the last testing period, so as to judge whether there is any extension.
8.4.6.4 Records of flaws
8.4.6.4.1 Records of the ultrasonic testing results of the flaws shall be made according
to such relevant technological specifications as the rules for periodic testing of
pressure vessels, rules for periodic testing of boilers, regulations for periodic testing of
in-service industrial pipelines, etc.
8.4.6.4.2 Critical dimensions (flaw position, length and through thickness dimension)
of permitted flaws can also be provided, as required, by the safety assessor based on
design, manufacture, use and other conditions. During the testing, records shall be
made only for flaws exceeding such critical dimensions, and submitted to the assessor
for treatment.
8.4.6.4.3 Contents of the records shall include flaw position, type, amplitude, indicating
length, through thickness dimension as well as flaw distribution diagram. The records
shall be signed by the tester and the reviewer.
9 Ultrasonic testing records and reports
9.1 Relevant information and data obtained during the testing shall be recorded in
detail according to the actual conditions of on-site operations. Ultrasonic testing
records shall comply with the provisions of NB/T 47013.1 and include at least the
following contents:
9.1.1 Edition of technological procedures or operating instruction number.
9.1.2 Testing technology grade
9.1.3 Testing equipment and appliances
a) Model & number of testing instruments;
b) Probe (type, size of crystal plate, refraction angle (value K), nominal frequency,
etc.);
c) Model of test specimen;
d) Couplant.
9.1.4 Testing technological parameters:
a) Testing scope, scanning position (face, side, etc.);
b) Testing proportion;
c) Scanning method;
d) Testing sensitivity;
e) Coupling compensation, etc.
9.1.5 Testing results:
a) Schematic diagram of testing position;
b) Flaw position, size, echo amplitude, etc.;
c) Evaluation grade of flaws;
d) Flaw type, through thickness dimension of the flaw (used for in-service pressure
equipment).
9.1.6 Signature of tester and reviewer
9.2 Testing reports shall be issued according to the testing records. Ultrasonic testing
report shall comply with the provisions of NB/T 47013.1 and at least include the
following contents:
a) Entrusted unit:
b) Testing technology grade;
c) Testing equipment and appliances: instrument model & number, probe, test
specimen, couplant;
d) Schematic diagram of testing: testing position, testing area as well as position,
size and distribution of the flaws detected.
Annex A
(Normative)
Requirements for electrical performance indicators of ultrasonic testing
instruments
A.1 See Table A.1 for requirements for electrical performance indicators of A-scan
pulse reflection type ultrasonic testing equipment.
Table A.1 -- Requirements for electrical performance indicators of ultrasonic
testing instruments
SN Performance Testing conditions Requirements for indicators
Requirements for stability
(1) Stability
after
preheating
After being preheated according to the
provisions of the factory documents, the
instrument shall be placed on a standard test
specimen by using an 0°longitudinal wave
probe with center frequency within 2 MHz ~ 6
MHz to make it generate a reference echo
signal; then adjust the reference signal
amplitude to 80% of full screen height and
observe the echo signal amplitude and the
positions changes on the time base every
10min; conduct the test for continuous 3
times.
Changes of the
amplitude of the
reference echo signal ≤
3 % of the full screen
height
Changes of the time
base position of the
reference echo signal ≤
1 % of the full screen
width
(2)
Showing
dithering
Use a waveform generator of any kind to
generate a signal with center frequency within
2 MHz ~ 6 MHz (voltage: 50 mv), connect the
instrument and generate a reference signal on
the screen, and adjust the instrument gain to
adjust the reference signal amplitude to 80 %
of full screen height. When the frequency is
increased by 1 Hz, determine the reference
signal amplitude and position changes on the
time base
Changes of the
amplitude of the
reference signal ≤ 3 %
of the full screen height
Changes of the time
base position of the
reference signal ≤ 1 %
of the full screen width
(3) Stability
against
voltage
changes
Provide the instrument with stabilized voltage
supply, adjust the output voltage of the
stabilized voltage supply to the intermediate
value of the ultrasonic instrument’s normal
working voltage, use a waveform generator of
any kind to generate a reference signal for the
ultrasonic instrument, and adjust the reference
Changes of the
amplitude of the
reference signal ≤ 3 %
of the full screen height
Changes of the time
base position of the
reference signal ≤ 1 %
signal amplitude to 80 % of full screen height.
When the output voltage of the stabilized
voltage supply decreases to the low voltage
causing alarming or automatic shutdown as
specified in the factory documents, observe
the reference signal amplitude and position
changes on the time base
of the full screen width
Requirements for transmitting performance indicators
(4)
Transmitte
d pulse
repetition
frequency
Use an oscilloscope to determine the
ultrasonic instrument’s transmitted pulse
repetition frequency, including the maximum,
minimum, any two intermediate values (4
values in total)
Difference between
measured value and set
value ≤ 10 % of the set
value
(5)
Effective
output
impedance
With each transmitted pulse voltage,
transmitted pulse width (taking the
intermediate value) as well as the optimal
transmitted pulse repetition frequency and
damping set value provided in the instrument
factory documents, determine the effective
output impedance of the ultrasonic
instruments
Effective output
impedance ≤ 50 Ω
(6)
Transmitte
d pulse
voltage
With the optimal damping set value provided
in the instrument factory documents, adjust
the transmitted pulse width and transmitted
pulse repetition frequency and determine each
transmitted pulse voltage of the instrument
Difference between
measured value and set
value (with 50 Ω load,
e.g. V50) ≤ 20 % of the
set value
(7)
Transmitte
d pulse
recoil
With each transmitted pulse voltage,
transmitted pulse width (taking the
intermediate value) as well as the optimal
transmitted pulse repetition frequency and
damping set value provided in the instrument
factory documents, determine the ratio of the
transmitted pulse recoil and the transmitted
pulse voltage peak of the ultrasonic instrument
Measured value of
transmitted pulse recoil
< 8 % of the transmitted
pulse voltage peak
(8)
Transmitte
d pulse
width
With each transmitted pulse voltage as well as
the optimal transmitted pulse repetition
frequency and damping set value provided in
the instrument factory documents, determine
the maximum, intermediate and minimum
value of the transmitted pulse width (3 values
in total)
Square-wave pulse:
difference between
measured value and set
value ≤ 10 % of the set
value
(9)
Transmitte
d pulse rise
With each transmitted pulse voltage as well as
the optimal transmitted pulse repetition
frequency and damping set value provided in
The maximum value of
the measured
transmitted pulse rise
time the instrument factory documents, adjust the
transmitted pulse width and determine the
transmitted pulse rise time
time ≤ 25 ns
Requirements for receiver performance indicators
(10)
Crosstalk
With each transmitted pulse voltage,
transmitted pulse width (taking the
intermediate value) as well as the optimal
transmitted pulse repetition frequency and
damping set value provided in the instrument
factory documents, measure the crosstalk
between the transmitting terminal and the
receiving terminal of the ultrasonic instruments
Crosstalk value > 50 dB
(11)
Transmitte
d pulse
rear blind
area
Use a waveform generator of any kind to
choose in sequence the set value of each
frequency band of the ultrasonic instruments
and measure the transmitted pulse rear blind
area of the ultrasonic instrument
Transmitted pulse rear
blind area < 10 μs
(12)
Dynamic
range
Use a waveform generator of any kind to
choose in sequence the set value of each
frequency band of the ultrasonic instruments
and use a calibrated external attenuator to
measure the dynamic range of the
measurement instrument
Available dynamic
range > 90 dB
(13)
Receiver
input
impedance
When the signal frequency is between 2.5
MHz and 5.0 MHz, set the attenuator of the
ultrasonic instrument to the maximum and the
minimum gain, and measure real and
imaginary parts of the receiver input
impedance
When the instrument
is adjusted to the
maximum gain, the real
part of the input
impedance, Rmax, shall:
50 Ω ≤ Rmax ≤ 1 KΩ, the
imaginary part shall:
Cmax ≤ 150 pF;
Corresponding to the
maximum and minimum
gains, the real part of
the input impedance
shall: (Rmax - Rmin)/Rmax <
0.1, and the capacitance
part of the input
impedance shall: (Cmax -
Cmin)/Cmax < 0.15
(14)
Amplifier
frequency
response
Use a waveform generator of any kind to
choose in sequence the set value of each
frequency band of the ultrasonic instruments
and use a calibrated external attenuator to
The difference
between the upper &
lower measured value
and the nominal value of
measure the amplifier frequency response of
the measurement instrument
each frequency
bandwidth ≤ 20 % of the
nominal value;
The frequency band
range of the receiving
part measured
according to -3 dB shall
include: 0.5 MHz ~ 10
MHz
(15)
Equivalent
input noise
Use a waveform generator of any kind to
choose in sequence the center frequency of
2.5 MHz and 5.0 MHz, and use a calibrated
external attenuator to measure the equivalent
input noise
For the square root of
each frequency band,
the wide-band noise
shall:
(16)
Attenuator
precision
Based on each frequency band set value,
compare the attenuator of the ultrasonic
instrument with the corresponding external
standard attenuator
Within any
continuous 20 dB range,
the attenuator’s
accumulative error ≤ 1.7
dB;
Within any
continuous 60 dB, the
attenuator’s
accumulative error ≤ 3
dB
(17)
Amplitude
linearity
Based on each frequency band set value, use
a calibrated external attenuator to change the
amplitude of the reference signal, and observe
the changes of the height of the signals on the
screen of the ultrasonic instrument
The maximum deviation
of the amplitude linearity
≤ 2 %
(18) Time
base
linearity
Choose a proper frequency band, use a signal
generator of any kind to generate 11 equally-
spaced sine wave pulse trains on the screen
of the ultrasonic instrument, and measure the
difference between the scale value and the
ideal value of the reference signal
The deviation between
the scale value and the
ideal value of the
reference signal ≤ 1 %
(19) Net
gain
Use a signal generator of any kind to generate
a reference signal on the screen of the
ultrasonic instrument, and use a calibrated
external attenuator to measure the net gain of
the ultrasonic instrument
Net gain of the
measured value ≥ 60 dB
Annex B
(Normative)
Requirements for performance indicators of probe used for ultrasonic testing
B.1 See Table B.1 for Requirements for performance indicators of probe used for
ultrasonic testing
Table B.1 -- Requirements for performance indicators of probe used for
ultrasonic testing
SN Performance Requirements for indicators
Basic
performance
requirements
(1) Center
frequency
Deviation between measured center frequency and
nominal frequency ≤10 % nominal frequency
(2) Bandwidth
Deviation between measured -6 dB and nominal
value ≤15 % of nominal value; wide-band narrow-
pulse probe: relative width of measured -6 dB
frequency band ≥ 60 %
(3) Impedance or
direct capacitance
Deviation between measured impedance module or
direct capacitance and nominal value ≤ 20 % of the
nominal value
(4) Relative pulse
echo sensitivity
Deviation between measured relative pulse echo
sensitivity and nominal value ≤ 3 dB
(5) Pulse width
Deviation between measured pulse width and
nominal value ≤ 25 % of nominal value; the pulse
duration measured based on the peak of the wide-
band narrow-pulse probe lateral wave decreasing 20
dB shall not exceed two periods
Performance
of single
crystal
straight
probe beam
(1) Acoustic beam
spread angle
Deviation between measured acoustic beam spread
angle and nominal value ≤ 10 % of the nominal value
or 2° (which is larger)
(2) Angle of
deviation and
offset
Angle of deviation ≤ 2°, offsetting the probe center ≤
1 mm
Performance
of single
crystal angle
probe beam
(1) Point of
incidence
Deviation between measured point of incidence and
marked point of incidence ≤ 1 mm; for angle probe
with crystal plate size ≤15 mm and center frequency
f ≤ 2 MHz, deviation between measured point of
incidence and marked point of incidence ≤ 2 mm
(2) Acoustic beam
angle
When center frequency f < 2 MHz, deviation
between measured acoustic beam angle and
nominal value ≤ 3°; when center frequency f ≥ 2
MHz, deviation between measured acoustic beam
angle and nominal value ≤ 2°
(3) Acoustic beam
spread angle
Deviation between measured acoustic beam spread
angle and nominal value ≤ 10 % of the nominal value
or 2° (which is larger)
(4) Angle of
deviation and
offset
Angle of deviation ≤ 2°, offsetting the probe
center≤1mm
Performance
of double
crystal
straight
probe beam
(1) Crosstalk Crosstalk dB difference > 30 dB
(2) Width of beam
cross section
Deviation between measured beam cross section
width and nominal value ≤ 20 % of the nominal value
Performance
of double
crystal angle
probe beam
(1) Crosstalk Crosstalk dB difference > 30 dB
(2) Acoustic beam
angle
Deviation between measured acoustic beam angle
and nominal value ≤ 2°
(3) Point of
incidence
Deviation between measured point of incidence and
marked point of incidence ≤ 1 mm
(4) Width of beam
cross section
Deviation between beam cross section width and
nominal value ≤ 20 % of the nominal value
Performance
of immersion
probe beam
(1) Acoustic beam
width
Deviation between acoustic beam width and nominal
value ≤ 20 % of the nominal value
(2) Acoustic beam
spread angle
Deviation between measured acoustic beam spread
angle and nominal value ≤ 10 % of the nominal value
or 2° (which is larger)
Performance
of focusing
probe beam
(1) Focal distance Deviation between measured focal distance and nominal value ≤ 20 % of the nominal value
(2) Focal region
width
Deviation between measured focal region width and
nominal value ≤ 20 % of the nominal value
(3) Focal region
length
Deviation between measured focal region length and
nominal value ≤ 20 % of the nominal value
Performance
of wide-band
narrow-pulse
probe beam
(1) Relative
frequency
bandwidth
No less than 60 %
(2) Acoustic beam
spread angle
Deviation between measured acoustic beam spread
angle and nominal value ≤ 10 % of the nominal value
or 2° (which is larger)
(3) Angle of
deviation and
offset
Angle of deviation ≤ 2°, offsetting the probe center ≤
1 mm
Annex C
(Normative)
Requirements for performance of double-crystal straight probe
C.1 Distance-amplitude characteristic curve
Use a test specimen as shown in Figure 1, measure its echo height at each thickness
(Unit: dB), and make a characteristic curve as Figure C.1. The characteristic curve
shall meet the following conditions:
a) The difference between the echo height measured at the limit thickness within
the usable range of the double-crystal straight probe and the maximum echo
height shall be within 0 dB ~ -6 dB;
b) The difference between the echo height measured at the thickness of 3 mm and
the maximum echo height shall also be within 0 dB ~ -6 dB.
Explanation:
t0 - Thickness when the step block has the maximum echo;
t - Limit thickness within the usable range of the double-crystal probe.
Figure C.1 -- Distance-amplitude characteristic curve of double-crystal straight
probe
C.2 Surface echo height
The surface echo height measured by the direct contact method shall be at least 40
dB lower than the maximum echo height corresponding to t0 as shown in Figure C.1.
C.3 Detection sensitivity
Echo height/dB
Plate thickness/mm
Move the probe to align it to the Φ5.6 mm flat-bottomed hole of the test specimen as
shown in C.2; the difference between its echo height and the maximum echo height
shall be within -10 dB ± 2 dB.
C.4 Effective beam width
Align the probe to the Φ5.6 mm flat-bottomed hole of the test specimen as shown in
C.2 and move it in the direction parallel to the acoustic wave parting plane, and
measure the beam width by the -6 dB method; for testing of steel plates used for
pressure equipment, the effective value shall be larger than 15 mm.
Figure C.2 -- Test specimen for testing the composite performance of the
instrument and the probe
All
Annex D
(Normative)
Ultrasonic testing methods and acceptance standard for plates used for
pressure equipment by using an angle probe
D.1 Scope
This annex stipulates the ultrasonic testing methods and acceptance standard for
testing non-layer flaws in the plates by using an angle probe, and takes them as the
supplementary for the testing using a straight probe.
D.2 Probe
D.2.1 In principle, we shall choose an angle probe with refraction angle of 45° (K1) and
the effective diameter of crystal plate shall generally be within Φ13 mm ~ 25 mm, but
probes with other refraction angle (value K) and effective diameter of crystal plate can
also be used.
D.2.2 The nominal frequency of probes shall be 2 MHz ~ 5 MHz.
D.3 Reference test specimen
D.3.1 The reference test specimen shall have the same or similar acoustic
characteristics with those of the plates to be tested, and the thickness difference shall
not exceed 10 %.
D.3.2 The artificial reflector on the reference test specimen is a V-shaped groove, with
an angle of 60°, the groove depth is 3 % of the plate thickness (maximum: 3.0 mm),
and the groove length shall be at least 25 mm.
D.3.3 The position of the V-shaped groove and the size of the reference test specimen
shall meet the requirements as shown in Figure D.1.
Figure D.1 -- Reference test specimen
D.3.4 For plates with thickness exceeding 50 mm, another calibration groove shall be
cut as specified in D.3.2 and D.3.3 on the other side of the plate.
D.4 Determination of distance-amplitude curve
D.4.1 For plates with thickness ≤ 50 mm
D.4.1.1 Place the probe on the side of the test specimen which has the groove to align
the acoustic beam to the wide side of the groove, and find out the first maximum
amplitude with the full span reflection, then adjust the instrument to make the maximum
amplitude of this reflected wave be 80 % of the full scale, and record the position of
the signal on the display screen.
D.4.1.2 Move the probe, without changing the instrument’s adjustment state, to get the
second full span signal, and find out the signal’s maximum reflected amplitude, and
record the position of the signal on the display screen.
D.4.1.3 Link the points determined on the display screen as specified in D.4.1.1 and
D.4.1.2 together, and the line formed is the distance-amplitude curve.
D.4.2 For plates with thickness > 50 mm ~ 250 mm
D.4.2.1 Align the probe beam to the groove on the back side of the test specimen, and
find out the first maximum amplitude with 1/2 span reflection. Adjust the instrument to
make the reflected amplitude be 80 % of the full scale and record the position of the
signal on the display screen.
D.4.2.2 Move the probe, without changing the instrument’s adjustment state, and align
the full span to the cutting groove and get the maximum reflected amplitude, and record
this amplitude point on the display screen.
Determined according to the sonic path distance tested
Cutting groove
D.4.2.3 Link the points determined on the display screen as specified in D.4.2.1 and
D.4.2.2 together, and the line formed is the distance-amplitude curve.
D.5 Scanning method
D.5.1 Scanning shall be conducted, on the rolling plane of the plates, along the grid
lines perpendicular and parallel to the plates’ main calendering direction, and the
center distance of the grid lines shall be 200 mm.
D.5.2 When finding the flaw signals, move the probe to get the maximum reflected
amplitude on the display screen.
D.5.3 For flaws with amplitude equal to or exceeding the distance-amplitude curve, we
shall record their positions, and move the probe to measure their length by -6 dB
method. For flaws with amplitude lower than the distance-amplitude curve, when the
indicating length is large, we shall also make records.
D.5.4 On each recorded position of flaw, we shall conduct 100 % angle probe and
straight probe testing at least within a 200 mm × 200 mm area from the recorded flaw
center.
D.6 Acceptance standard
Any flaw signals equal to or exceeding the distance-amplitude curve shall be deemed
as unqualified. But during the aided testing by using the longitudinal wave method, if
the flaws are found to be layer ones, then we shall follow the provisions in 5.3.
Annex E
(Normative)
Ultrasonic testing methods (by using an angle probe) and quality classification
of steel forgings used for pressure equipment
E.1 Scope
This annex is applicable to the axial ultrasonic testing by using an angle probe for ring
or cylinder forgings used for pressure equipment, and applicable to circumferential
ultrasonic testing by using an angle probe for ring or cylinder forgings with inner-outer
diameter ratio equal to or larger than 65 %.
E.2 Probe
E.2.1 The nominal frequency of the probe shall mainly be 2 MHz ~ 5 MHz.
E.2.2 The area of probe’s crystal plate shall be 80 ~ 625 square millimeters.
E.2.3 In principle, we shall adopt a probe with refraction angle of 45°(K1), but probes
with other refraction angles (value K) can also be used according to different geometric
shapes and inner-outer diameter ratios of the base material.
E.3 Reference test specimen
To adjust the sensitivity, we can make the reference test specimen by using the
machining allowance of wall thickness or length of the pieces to be tested. On the inner
and outer surfaces of the forgings, the paralleled V-shaped grooves processed along
the axial and circumferential directions shall be taken as the standard grooves. The V-
shaped groove shall be 25 mm long, its depth shall be 1 % of the thickness of the
forgings, and the angle shall be 60°. Other equivalent reflectors (e.g. edge and angle
reflection, etc.) can also be used.
E.4 Testing method
E.4.1 Scanning method
The scanning method is shown in Figure E.1.
Figure E.1 -- Scanning method of angle probe testing for forgings
E.4.2 Determination of distance-amplitude curve
Align the probe, from the external circular surface, to the standard groove on the inner
circular surface, adjust the gains to make the maximum reflection height be 80% of the
full scale, and mark this value on the panel and take it as the scanning sensitivity;
move the probe, without changing the instrument’s adjustment state, to test the
standard groove on the outer circular surface, and mark the maximum reflection height
on the panel. Link the above two points together by a straight line and extend the line
to draw the distance-amplitude curve which shall cover the whole testing scope. The
scanning sensitivity during the testing of the inner circular surface shall also be
determined according to the above method, but the wedge of the probe shall be
consistent with the inner circle curvature.
E.5 Records
E.5.1 The effective area of the flaws shown on the fluorescent screen shall be the area
by linking any two points of the distance-amplitude curve.
E.5.2 Record the reflected wave and the position of flaws with amplitude being 50 %
or more of the distance-amplitude curve. The flaw indicating length shall be determined
by the -6 dB method. When the distance between two adjacent flaws is equal to or less
than 25 mm, they shall be deemed as one flaw.
E.6 Quality classification
E.6.1 The flaw quality classification with amplitude higher than the distance-amplitude
curve shall be deemed as Class III.
E.6.2 Flows with amplitude being 50 % ~ 100 % of the distance-amplitude curve shall
be classified according to Table E.1.
All
Table E.1 -- Flaw quality classification
Quality classification Indicating length of single flaw
I ≤ 1/3 wall thickness, and ≤ 100 mm
II ≤ 2/3 wall thickness, and ≤ 150 mm
III Higher than Class II
Annex F
(Normative)
Ultrasonic testing methods (by using an angle probe) for austenitic steel
forgings used for pressure equipment
F.1 Scope
This annex is applicable to the axial ultrasonic testing by using an angle probe for ring
or cylinder austenitic steel forgings used for pressure equipment, and applicable to
circumferential ultrasonic testing by using an angle probe for ring or cylinder austenitic
steel forgings with inner-outer diameter ratio equal to or larger than 65 %.
F.2 Probe
F.2.1 The nominal frequency of the probe shall be 1 MHz ~ 2.5 MHz.
F.2.2 The area of probe’s crystal plate shall be 300 ~ 625 square millimeters.
F.2.3 The refraction angle of the probe (Value K) shall generally be 35° ~ 63° (K0.7 ~
K2).
F.3 Reference test specimen
To adjust the sensitivity, we can make the reference test specimen by using the
machining allowance of wall thickness or length of the pieces to be tested. On the inner
and outer surfaces of the forgings, the paralleled V-shaped grooves processed along
the axial and circumferential directions shall be taken as the standard grooves. The V-
shaped groove shall be 25 mm long, its depth t shall be 3 % or 5 % of the wall thickness
of the forgings, and the angle shall be 60°. Other equivalent reflectors (e.g. edge and
angle reflection, cross bore, etc.) can also be used.
F.4 Scanning method
The scanning method is shown in Figure F.1.
a) Circumferential scanning b) Axial scanning
Figure F.1 -- Scanning method for testing of austenitic forgings
F.5 Determination of distance-amplitude curve
F.5.1 During the cutting-groove method, we generally need to place the probe on the
outer circular surface, and the acoustic beam shall be perpendicular to the cutting
groove’s length direction. Move the probe and adjust the instrument’s sensitivity to
make the echo height of the second reflection of the outer wall groove (W-type
reflection) and the second reflection of the inner wall groove (N-type reflection) be at
least 20 % of the full scale. Link the first and second echo peak points of the outer wall
groove or the first and second echo peak points of the inner wall groove together, and
the line formed is the full-span calibration distance-amplitude curve.
F.5.2 If we can’t, by using full span calibration, get the second echo which is at least
20 % of the full scale either from the inner wall groove or the outer wall groove, then
half span calibration shall be adopted (the inner and outer walls shall respectively have
a groove without interference). To make the height of the first echo from the outer wall
groove be at least 20 % of the full scale. Link the peak points of the first echo of the
inner wall groove and that of the outer wall groove, and the line formed shall be
deemed as the half span calibration distance-amplitude curve.
F.5.3 For cylinder forgings with inner diameter less than 450 mm and length exceeding
900 mm, scanning is usually not conducted from the inner surface.
All
Annex G
(Normative)
Ultrasonic testing method and quality classification of the welding overlay of
pressure equipment
G.1 Scope
This annex is applicable to the ultrasonic testing method and quality classification for
flaws in the welding overlay of austenitic stainless steel and nickel alloys, flaws of
disconnection between the welding overlay and the base materials, as well as flaws
beneath the welding overlay.
G.2 Testing method
G.2.1 Testing of the welding overlay shall generally be conducted at the welding
overlay side.
G.2.2 The testing of welding overlay shall be conducted by using double-crystal
straight probe and longitudinal-wave double-crystal angle probe.
G.2.3 The testing of the base material side shall be conducted by using single-crystal
straight probe and longitudinal-wave angle probe.
G.3 Probe
G.3.1 Double-crystal probe
G.3.1.1 The angle between the two acoustic beams of the double-crystal probe
(straight or angle probe) shall make the effective acoustic field cover the whole testing
area make the probe have the maximum sensitivity to this area. The sound insulation
effect between two crystal plates shall be good.
G.3.1.2 The convergence zone of double-crystal probes shall be at the place where
the welding overlay and the base material combine. The nominal frequency of the
probe shall be 2 MHz ~ 5 MHz. The refraction angle of the angle probe is generally
about 70°, and probes with other refraction angle can also be used when needed, but
the angle shall not be less than 60°.
G.3.2 Single-crystal straight probe
Generally, the diameter shall not exceed Φ30 mm, and the nominal frequency shall be
2 MHz ~ 5 MHz.
G.3.3 Longitudinal-wave angle probe
We generally choose the probe with a refraction angle of 45°(K1) and nominal
frequency of 2 MHz ~ 5 MHz.
G.4 Reference test specimen
G.4.1 The surface state of the welding overlay of the reference test specimen shall be
the same as that of the welding overlay of the pieces.
G.4.2 The reference test specimen shall adopt the same welding technology as that of
the product components, and can also be made by overlaying the redundant parts or
extended parts.
G.4.3 The testing of double-crystal straight probe shall adopt T1 test specimen, the
base material’s thickness T shall be at least 2 times that of the welding overlay, and
the thickness of the welding overlay of the test specimen shall be equal to or larger
than that of the welding overlay of the pieces tested. T1 test specimen is shown in G.1.
Figure G.1 -- T1 test specimen
G.4.4 Testing using longitudinal-wave double-crystal angle probe shall adopt T2 test
specimen, the base material’s thickness T shall be at least 2 times that of the welding
overlay, and the thickness of the welding overlay of the test specimen shall be equal
to or larger than that of the welding overlay of the pieces tested. T2 test specimen is
shown in G.2.
Welding overlay
Base material
Figure G.2 -- T2 test specimen
G.4.5 Testing using single-crystal straight probe and longitudinal-wave angle probe
shall adopt T3 test specimen. The thickness difference T between the base material of
the pieces to be tested and that of the test specimen shall not exceed 10 %. T3 test
specimen is shown in G.3.
Figure G.3 -- T3 test specimen
G.5 Sensitivity
G.5.1 Calibration for T1 test specimen
Welding overlay
Base material
Welding overlay
Base material
a) During the testing of flaws in the welding overlay, put the double-crystal straight
probe on the welding overlay surface of the test specimen, and use the four Φ3
mm flat-bottomed holes on the right side of test specimen to draw the distance-
amplitude curve and take it as the reference sensitivity;
b) During the testing of flaws beneath the welding overlay, put the double-crystal
straight probe on the welding overlay surface of the test specimen, move the
probe to get the maximum amplitude from the Φ3 mm flat-bottomed hole of the
base material on the test specimen, and adjust the attenuator to make the echo
amplitude be 80 % of the full scale and take it as the reference sensitivity;
c) During the testing of flaw of disconnection between the base material and the
welding overlay, put the double-crystal straight probe on the welding overlay
surface of the test specimen, move the probe to get the maximum amplitude
from the Φ10 mm flat-bottomed hole, and adjust the attenuator to make the echo
amplitude be 80 % of the full scale and take it as the reference sensitivity.
G.5.2 Calibration for T2 test specimen
a) During the testing of flaws in the welding overlay, put the longitudinal-wave
double-crystal angle probe on the welding overlay surface of the test specimen,
and use the four Φ1.5 mm cross bores on the right side of test specimen to draw
the distance - amplitude curve and take it as the reference sensitivity;
b) During the testing of flaws beneath the welding overlay, put the longitudinal-wave
double-crystal angle probe on the welding overlay surface of the test specimen,
move the probe to get the maximum amplitude from the Φ1.5 mm cross bore of
the base material on the test specimen, and adjust the attenuator to make the
echo amplitude be 80 % of the full scale and take it as the reference sensitivity.
G.5.3 Calibration for T3 test specimen
a) During the testing of flaws in the welding overlay by using the single-crystal
straight probe, put the probe on one side of the base material, adjust the gains
to make the echo amplitude of the Φ3 mm flat-bottomed hole be 80 % of the full
scale and take it as the reference sensitivity;
b) During the testing of flaws in the welding overlay by using the longitudinal-wave
angle probe, put the probe on one side of the base material, adjust the gains to
make the echo amplitude of the Φ1.5 mm cross bore be 80 % of the full scale
and take it as the reference sensitivity;
c) During the testing of flaws of disconnection between the base material and the
welding overlay, put the single-crystal straight probe on one side of the base
material, to make the echo amplitude of the Φ10 mm flat-bottomed hole be 80%
of the full scale and take it as the reference sensitivity.
G.5.4 The scanning sensitivity shall be the reference sensitivity plus 6 dB.
G.6 Testing requirements
G.6.1 The testing scope shall include the welding overlay and the base material area
within 4 mm beneath the welding overlay.
G.6.2 With longitudinal-wave double-crystal angle probe, the testing shall be
conducted by moving the probe in the overlaying direction and in the direction
perpendicular to the overlaying direction respectively.
G.6.3 During the testing with double-crystal straight probe, move the prove in the
direction perpendicular to the overlaying direction. During the scanning, it shall be
ensured that the sound insulating layer for isolating piezoelectric elements shall be
parallel to the overlaying direction.
G.6.4 The equivalent size of the flaw shall generally be determined by the -6 dB
method.
G.7 Quality classification
G.7.1 Quality classification of the welding overlay is shown in G.1.
G.7.2 Flaws beneath the welding overlay shall generally, in addition to the non-crack-
type flaws of the base material, be determined as Class III.
Table G.1 -- Ultrasonic testing and quality classification of welding overlay
Class
of
flaw
Flaws in the welding overlay Flaw of disconnection
between the welding
overlay and the base
material
Double-crystal straight probe,
straight probe
Longitudinal-wave double-
crystal angle probe,
longitudinal-wave angle
probe
I Equivalent size < Φ3 mm Equivalent size < Φ1.5 -2 dB
Disconnection area with
flaw long diameter ≤ 25
mm
II Equivalent size ≥ Φ3 ~ Φ3 + 6 dB and length ≤ 30 mm
Equivalent size ≥ Φ1.5 - 2
dB ~ Φ1.5 + 4 dB and length
≤ 30 mm
Disconnection area with
flaw long diameter ≤ 40
mm
III When flaw equivalent size or length exceeds Class II or the flaw belongs to crack-type flaws Exceeding Class II
Annex H
(Normative)
Ultrasonic testing method and quality classification of the butt joints of
pressure equipment made by aluminum & aluminum alloy and titanium
H.1 Scope
H.1.1 This annex stipulates the ultrasonic testing method and quality classification of
the butt joints of pressure equipment made by aluminum & aluminum alloy and titanium.
H.1.2 This annex is applicable to the ultrasonic testing of the butt joints of pressure
equipment made by aluminum & aluminum alloy and titanium with thickness equal to
or larger than 8 mm ~ 80 mm.
H.1.3 This annex is neither applicable to the ultrasonic testing of circumferential butt
joints with outer diameter less than 159 mm nor to the ultrasonic testing of longitudinal
butt joints with outer diameter equal to or less than 250 mm and inner-outer diameter
ratio less than 70 %.
H.2 Reference test specimen
H.2.1 The texture of the reference test specimen shall be the same of similar as the
acoustic performance of the plates to be tested.
H.2.2 The size and shape of the test specimen are shown in Table H.1 and Figure H.1.
Table H.1 -- Size of the reference test specimen Unit: mm
Test specimen
No.
Base material
nominal
thickness t
Specimen
thickness T
Cross bore
position
Cross bore
diameter
1 ≥8~40 45 5, 15, 25, 35 φ2.0
2 >40~80 90 10, 30, 50, 70 φ2.0
a) Specimen No.1
b) Specimen No.2
Figure H.1 -- Reference test specimen
H.3 Testing area
The testing area shall comply with the provisions as specified in 6.3.4.
H.4 Preparation of testing surface
Preparation of testing surface shall comply with the provisions as specified in 6.3.5.
H.5 Selection of probe
Selection of probe shall comply with the provision as specified in 6.3.6.
H.6 Drawing of the distance-amplitude curve
The distance-amplitude curve shall be drawn based on the testing conducted on the
reference test specimen. The curve is mainly composed of evaluation line (EL), scale
line (SL) and rejection line (RL), as shown in Figure H.2. The sensitivity of the distance-
amplitude curve is shown in Table H.2. If the distance-amplitude curve is drawn on the
display screen, it shall, within the testing scope, not be less than 20 % of the full scale
of the display screen.
Figure H.2 -- Distance-amplitude curve
Table H.2 -- Sensitivity of the distance-amplitude curve
Evaluation line Scale line Rejection line
Φ2 mm - 18 dB Φ2 mm - 12 dB Φ2 mm - 4 dB
H.7 Scanning sensitivity
The scanning sensitivity shall not be less than the sensitivity of the evaluation line. For
this case, the evaluation line height at the maximum sonic path distance within the
testing scope shall not be less than 20 % of the full scale of the fluorescent screen.
H.8 Scanning method
The scanning method shall comply with the provisions as specified in 6.3.9.
H.9 Flaw quantitation
Flaw quantitation shall comply with the provisions as specified in 6.3.13.
H.10 Assessment of flaw
Assessment of flaw shall comply with the provisions as specified in 6.3.14.
H.11 Quality classification
H.11.1 The welding joints shall not have such flaws as cracks, incomplete fusion,
incomplete welding, etc.
H.11.2 Flaws under the evaluation line shall all be deemed as Class I.
H.11.3 The quality classification of welding joints shall comply with the provisions as
shown in Table H.3.
Table H.3 -- Ultrasonic testing method and quality classification of the butt
Amplitude/dB Rejection line (RL)
Scale line (SL)
Evaluation line (EL)
Distance/mm
joints of pressure equipment made by aluminum & aluminum alloy and
titanium
Unit: mm
Class Base material nominal thickness t
Area where reflected
wave amplitude exists
Indicating length of
permitted single flaws
8 ~ 40 I ≤ 20 > 40 ~ 80 ≤ 40
8 ~ 40 II ≤ 10 > 40 ~ 80 ≤ t/4, not exceeding 20
II
8 ~ 40 I ≤ 30 > 40 ~ 80 ≤ 60
8 ~ 40 II ≤ 15 > 40 ~ 80 ≤ t/3, not exceeding 25
III 8 ~ 80
II Higher than Class II
III All flaws
I Higher than Class II
Annex I
(Informative)
Ultrasonic testing method and quality classification of the butt joints of
austenitic stainless steel
I.1 Scope
This annex stipulates the ultrasonic testing method and quality classification of the butt
joints of austenitic stainless steel with base material nominal thickness within 10 mm
~ 80 mm.
I.2 Testing personnel
Personnel who conduct testing according to this annex shall take a certain period of
training relating to the ultrasonic testing method of the butt joints of austenitic stainless
steel. The personnel shall be familiar with material characteristics, welding
characteristics and weld microstructure and acoustic characteristics of austenitic steel
as well as acoustic field characteristics of narrow-pulse double-crystal focusing probe.
They shall also be able to make correct analysis and adjustment and take proper
measures when facing problems probably found in the testing.
I.3 Probe, instrument and composite performance
I.3.1 Probe
Longitudinal-wave double-crystal angle probe, longitudinal-wave focusing angle probe,
narrow-pulse longitudinal-wave single-crystal angle probe, etc. are recommended in
this annex.
I.3.1.1 The nominal frequency of the probe shall be within 1 MHz ~ 5 MHz.
I.3.1.2 We generally choose probes with a refraction angle of 45° (K1), but probes with
other refraction angles can also be used when needed.
I.3.1.3 During the testing using the double-crystal longitudinal-wave probe or the
focusing longitudinal-wave probe, we shall choose the probe according to the
convergence range of the acoustic beam and the testing depth. When the wall
thickness is large, we can conduct zone scanning by using multi-probe thicknesses.
The intersection of each scanning zone shall not be less than 15 %. Recommendations
relating to probe’s refraction angle (value K) and acoustic beam convergence depth
under different testing depths are given in Table I.1.
Table I.1 -- Recommendations of double-crystal longitudinal-wave angle probe
or focusing longitudinal-wave angle probe
Base material nominal
thickness t/mm
Probe’s refraction angle
(value K) Convergence depth/mm
10 ~ 30 45° ~ 63° (1 ~ 2) 20
30 ~ 50 45° ~ 56° (1 ~ 1.5) 40 ~ 50
50 ~ 80 35° ~ 45° (0.7 ~ 1) 60 ~ 80
I.3.2 Composite performance
The testing instrument selected shall match the probe selected so as to get the optimal
sensitivity and signal-noise ratio. The distance between the two distance-amplitude
curves drawn respectively by the acoustic beam getting through the parent metal and
through the welding joints shall generally be less than 10 dB. The scanning sensitivity
shall make the reflector echo height at the maximum sonic path distance within the
testing scope be over than 20 % and the signal-noise ratio reach 2: 1.
I.4 Test specimen
I.4.1 The material of the reference test specimen shall be the same as that of the
material to be tested. A butt joint shall be set in the middle of the test specimen. The
groove type of the welding joint shall be similar to that of the welding joint to be tested,
and shall be made by the same welding technology.
I.4.2 In principle, the allocation and quantity of the artificial reflector on the test
specimen shall be determined according to the thickness of the pieces to be tested.
I.4.3 The shape and size (recommended) of the reference test specimen are shown in
Figure I.1 ~ I.3. The reference test specimen shown in Figure I.1 is applicable to the
base material nominal thickness within 10 mm ~ 20 mm, the reference test specimen
shown in Figure I.2 is applicable to the base material nominal thickness within 20 mm
~ 40 mm, and the reference test specimen shown in Figure I.3 is applicable to the base
material nominal thickness within 40 mm ~ 80 mm.
Figure I.1 -- Reference test specimen
All
Figure I.2 -- Reference test specimen
All
Figure I.3 --Reference test specimen
I.5 Distance - amplitude curve
I.5.1 The distance - amplitude curve shall be drawn based on the data measured on
the reference test specimen by using selected combination of probe and instrument.
During the testing conducted at the two sides of the welding seam, use the cross bore
at the center of the welding seam to draw the distance-amplitude curve and determine
the sensitivity and evaluation; during the testing conducted at one side of welding seam,
the acoustic beam shall go through the weld metal and use the cross bore at the fusion
zone to draw the distance - amplitude curve and determine the sensitivity and
evaluation. The area between the evaluation line and the scale line shall be deemed
as Zone I; the area between the scale line and the rejection line shall be deemed as
Zone II; and the area above the rejection line shall be deemed as Zone III. The
sensitivity of the rejection line (RL), the scale line (SL) and the evaluation line (EL) is
shown in Table I.2.
Table I.2 Sensitivity of the distance-amplitude curve
Base material nominal
thickness t/mm T ≤ 50 50 < T ≤ 80
Rejection line Φ2 × 40 + 3 dB Φ2 × 40 + 6 dB
All
Scale line Φ2 × 40 - 2 dB Φ2 × 40
Evaluation line Φ2 × 40 - 8 dB Φ2 × 40 - 6 dB
I.5.2 To compare the welding joint microstructure with the parent metal, we can make
the acoustic beam only go through the parent metal zone, and use the cross bore at
the fusion zone to draw another distance-amplitude curve [Figure I.4, (a) line].
Figure I.4 -- Schematic diagram of distance-amplitude curve
I.6 Preparation for testing
I.6.1 Testing face
In principle, the testing shall be conducted by adopting the single traverse technique
(straight beam method) at two sides and two faces of the welding joints. If the testing,
subject to geometrical conditions, can only be conducted at one side or one face of the
welding joint, the surplus height of the welding joint shall be grinded smooth or we can
change the value K. The testing shall be conducted by using the longitudinal-wave
angle probe with two or more refraction angles, which shall, as far as possible, cover
the whole testing area.
I.6.2 Probe moving area
I.6.2.1 Impurities such as welding spatter, scrap iron and oily dirt shall be cleared away
from the probe moving area at the two sides of the welding joint. For welding joint, the
surplus height shall be grinded to the same level of the adjacent parent metal.
I.6.2.2 The probe moving area N shall comply with formula (I.1):
N ≥ 1.5Kt ……………………………………………… (I.1)
where:
t - base material nominal thickness, mm;
Amplitude/dB
Rejection line (RL)
Scale line (SL)
Evaluation line (EL)
Distance/mm
Reference line (a)
K - tan β, β is the refraction angle of the probe.
I.7 Testing
I.7.1 General
I.7.1.1 The scanning sensitivity shall not be lower than the sensitivity of the evaluation
line. For this case, the height of the evaluation line at the maximum sonic path distance
within the testing scope shall not be less than 20 % of the full scale of the fluorescent
screen. If the signal-noise ratio is permitted, it shall have an increase of 6 dB.
I.7.1.2 For echo with amplitude exceeding the evaluation line, we shall judge whether
it is flaw echo according to the probe position, direction, reflected wave position as well
as the condition of the welding joint. To prevent the interference of the deformed
transverse wave, special attention shall be paid to the leading echoes on the display
screen.
I.7.2 Testing of longitudinal flaws
I.7.2.1 To test the longitudinal flaws, the angle probe shall conduct zigzag scanning in
the direction perpendicular to that of the welding joint. The moving of the probe shall
ensure that the acoustic beam can scan the whole section of the welding joint as well
as the heat-affected zone. During the scanning, the prove shall also rotates within 10°
~ 15°. If the probe cannot rotate, the covering area of the probe’s acoustic beam shall
be properly increased.
I.7.2.2 To determine flaw position, direction and shape, observe the dynamic pattern
or distinguish between defect wave and spurious signal, the following four basic
scanning methods of the probe can be adopted: front and back, right and left, rotation,
circle. Aided testing can also be conducted at the flaw position by using the straight
probe.
I.7.3 Testing of transverse flaws
I.7.3.1 For welding joint with the surplus height being saved, the scanning can be
conducted at the edge of the two sides of the welding joint by an angle probe, the
intersection angle between the probe and the center line of the welding joint shall not
be more than 10°, see Figure I.5 a).
I.7.3.2 For welding joint with the surplus height being moved, the parallel scanning
shall be conducted by the probe placed, in two different directions, on the surface of
the welding joint, see Figure I.5 b).
a) oblique parallel scanning b) parallel scanning
Figure I.5 -- Parallel and oblique parallel scanning
I.8 Flaw quantification
Flaw quantification shall comply with the provisions specified in 6.3.13.
I.9 Flaw evaluation
I.9.1 Attention shall be paid to echoes exceeding the evaluation line to see whether
there is any dangerous flaw such as crack. Evaluation shall be made according to flaw
position, dynamic patterns and technological features, and if correct evaluation fails to
be made, other methods shall be adopted for a comprehensive evaluation.
I.9.2 When the spacing between two adjacent flaws is less than the length of the
smaller flaw, they shall be deemed as a single flaw, and the sum of the lengths of the
two flaws shall be deemed as the indicating length of the single flaw. When strip flaws
are basically distributed on one line, the distance between two ends shall be taken as
the spacing; for spot flaws, the distance between the centers of two flaws shall be
taken as the spacing.
I.10 Quality classification
I.10.1 Such flaws as cracks, incomplete fusion and incomplete-penetration weld are
not allowed to appear on the welding joints.
I.10.2 Flaws under the evaluation line shall be deemed as Class I.
I.10.3 Quality classification of welding joints shall comply with Table I.3.
Table I.3 -- Ultrasonic testing and quality classification of butt joints of
austenitic stainless steel
Class Base material nominal thickness t/mm
Area where reflected wave
amplitude exists
Indicating length of
permitted single flaws
I 10 ~ 80 I ≤ 40 II L ≤ t/3, min: 10
II 10 ~ 80 I ≤ 60 II L ≤ 2t/3, min: 12; max:
40
III 10 ~ 80
II Higher than Class II
III All flaws (indicating length of any flaw)
I Higher than Class II
Annex J
(Normative)
Ultrasonic testing method of the curved longitudinal butt joints of pressure
equipment
J.1 Scope
J.1.1 This annex is applicable to the ultrasonic testing of longitudinal butt joints with
the curvature radius of the testing faces of the pressure equipment being 50 mm ~ 250
mm.
J.1.2 This annex is not applicable to the ultrasonic testing of longitudinal butt joints
with inner-outer diameter ratio less than 70 % (ratio between base material nominal
thickness and outer diameter is larger than 15 %).
J.2 Reference test specimen RB-L
J.2.1 Shape and size of the test specimen shall comply with Table J.1 and Figure J.1.
Table J.1 -- Size of RB-L test specimen Unit: mm
RB-L
No.
Base material
nominal thickness
t/mm
Test specimen
thickness T Cross bore depth
Cross bore
diameter
RB-L-1 ≥ 6 ~ 20 25 5, 10, 20 Φ2.0
RB-L-2 > 20 ~ 50 60 5, 10, 20, 30, 40, 50 Φ2.0
Note: When the base material nominal thickness t is larger than 50 mm, the test specimen
width shall comply with the requirements as specified in 6.3.10.1, the minimum cross bore
depth can be 10 mm, the depth spacing shall not exceed 20 mm, the test specimen thickness
is equal to or larger than the base material nominal thickness.
J.2.2 The test specimen length L shall be determined according to the sonic path
distance used.
J.2.3 The distance between the specimen reflector and the further side of the specimen,
L1, shall generally be larger than KT + 30 mm, and the distance between the reflector
and one side of the specimen, L2, shall generally be larger than 2KT (T means the
specimen thickness).
J.2.4 The curvature radius of the reference test specimen shall be within 0.9 ~ 1.1
times of the curvature radius of the testing faces of the base material.
J.2.5 The texture of the test specimen shall be the same as or similar to that of the
base material (acoustic characteristic).
a) RB-L-1 reference test specimen
b) RB-L-2 reference test specimen
Figure J.1 -- Schematic diagram of RB-L test specimen
J.3 Probe
J.3.1 During the testing, the stable contact between the probe and the base material
shall be ensured.
J.3.2 The probe’s refraction angle (Value K) can be selected according to Table J.2.
Table J.2 -- Recommendation form for refraction angle (Value K) of probes used
for ultrasonic testing of curved longitudinal butt joints
Ratio of thickness and radius t/D (%) Refraction angle (value K)
t/D ≤ 2.0 40° ~ 70° (0.84 ~ 2.75)
2.0 < t/D ≤ 5.0 40° ~ 63° (0.84 ~ 2)
5.0 < t/D ≤ 10.0 40° ~ 45° (0.84 ~ 1)
10.0 < t/D ≤ 15.0 40° (0.84)
J.4 Distance-amplitude curve
J.4.1 The distance-amplitude curve shall be drawn on the RB-L test specimen.
J.4.2 The sensitivity of the distance-amplitude curve shall comply with Table 27
(regardless the influence of specimen width differences).
J.5 Testing
J.5.1 Probe’s nominal frequency, testing faces, as well as the wide of the probe’s
moving area shall comply with Table J.3.
J.5.2 Number of probes with different refraction angles (value K), testing of transverse
flaws, etc. shall also meet the requirements of Level B shown in Table N.1 Testing
Technology.
J.5.3 The scanning sensitivity shall not be lower than that of the evaluation line.
J.5.4 The scanning methods shall, as far as possible, comply with the provisions as
specified in 6.3.9.
J.6 Flaw quantification
Flaw quantification shall comply with the provisions as specified in 6.3.13.
J.7 Flaw evaluation
Flaw evaluation shall comply with the provisions as specified in 6.3.14.
Table J.3 -- Recommendation form of probe’s nominal frequency, testing faces,
as well as the wide of the probe’s moving area
Possibility of
inner/outer
wall testing
Base material
nominal thickness
t/mm
Probe’s
nominal
frequency
MHz
Testing faces (sides)
Width of the
probe’s moving
area
Only for 6 ≤ t ≤ 30 4~5 Double sides of outer 1.25P
outer wall
(convex
surface)
wall (convex surface)
30 < t ≤ 60 2 ~ 5 Double sides of outer wall (convex surface) -1.25P
t > 60 2 ~ 2.5 Double sides of outer wall (convex surface) 0.75P
Both
available
6 ≤ t ≤ 30 4 ~ 5
Double sides of outer
wall (convex surface)
or double sides of
inner wall (concave
surface)
1.25P
30 < t ≤ 60 2 ~ 5
Double sides of outer
wall (convex surface)
or double sides of
inner wall (concave
surface)
1.25P
t > 60 2 ~ 2.5
Double sides of outer
wall (convex surface)
and double sides of
inner wall (concave
surface)
0.75P
Note: P means the span of the testing faces
Annex K
(Normative)
Ultrasonic testing method of the curved circumferential butt joints of pressure
equipment
K.1 Scope
This annex is applicable to the ultrasonic testing of circumferential butt joints with the
curvature radius of the testing faces of the pressure equipment being 80 mm ~ 250
mm.
K.2 Reference test specimen RB-C
K.2.1 The shape and size of the reference test specimen RB-C are shown in Figure
K.1.
K.2.2 The length of the test specimen, L, shall be determined according to the sonic
path distance used, which shall generally be larger than 4KT (T means the test
specimen thickness).
K.2.3 The distance between the specimen reflector and one side of the specimen, L1,
shall generally be larger than 2.5KT.
K.2.4 The width of the test specimen, W, shall be determined according to the formula
(5) in 6.3.10.1.
K.2.5 The curvature radius of the testing faces of the base material shall be 0.9 ~ 1.5
times of the curvature radius of the reference test specimen.
K.2.6 The difference between the test specimen thickness and the base material
nominal thickness shall not exceed 20 % of the latter.
K.2.7 The texture of the test specimen shall be the same as or similar to that of the
base material.
Figure K.1 -- Schematic diagram of RB-C
K.3 Probe
K.3.1 During the testing, the stable contact between the probe and the base material
shall be ensured.
K.3.2 The probe’s refraction angle (value K) can be selected according to Table 25,
and the probe’s nominal frequency can be selected according to Table K.1.
K.4 Distance - amplitude curve
K.4.1 The distance - amplitude curve shall be drawn on the RB-C test specimen. The
sensitivity of the distance - amplitude curve shall comply with Table 27 (regardless the
influence of specimen width differences)
K.4.2 If the distance - amplitude curve is drawn by using the CSK-II A test specimen,
correction shall be conducted on the RB-C test specimen.
K.5 Testing
K.5.1 The testing faces shall be selected according to Table K.1.
K.5.2 Number of probes with different refraction angles (value K), testing of transverse
flaws, etc. shall also meet the requirements of Level B shown in Table N.1 Testing
Technology.
K.5.3 Scanning method
The scanning method shall, as far as possible, comply with the provisions as specified
in 6.3.9.
K.6 Flaw quantification
Flaw quantification shall comply with the provisions as specified in 6.3.13.
K.7 Flaw evaluation
Flaw evaluation shall comply with the provisions as specified in 6.3.14.
Table K.1 -- Recommendation form of probe’s nominal frequency, testing faces,
as well as the wide of the probe’s moving area
Possibility of
inner/outer
wall testing
Base material
nominal thickness
t/mm
Probe’s nominal
frequency
MHz
Testing faces (sides)
Width of the
probe’s moving
area
Only for outer
wall (convex
surface)
6 ≤ t ≤ 40 2 ~ 5 Double sides of outer wall (convex surface) 1.25P
40 < t ≤ 100 2 ~ 2.5 Double sides of outer wall (convex surface) 1.25P
t > 100 2 ~ 2.5 Double sides of outer wall (convex surface) 0.75P
Both
available
6 ≤ t ≤ 40 2 ~ 5
Double sides of outer
wall (convex surface)
or double sides of inner
wall (concave surface)
1.25P
40 < t ≤ 100 2 ~ 2.5
Double sides of outer
wall (convex surface)
or double sides of inner
wall (concave surface)
1.25P
t > 100 2 ~ 2.5
Double sides of inner
and outer wall (convex
and concave surfaces)
0.75P
Note: P means the span of the testing faces
Annex L
(Normative)
Ultrasonic testing method of fillet joints for nozzles and shells (or heads) of
pressure equipment
L.1 Scope
L.1.1 This annex stipulates the ultrasonic testing method of fillet joints for nozzles and
shells (or heads).
L.1.2 For the purpose of this annex, the following conditions shall be satisfied:
a) For inserted fillet joints for nozzles and shells (or heads):
1) The curvature radius of the testing faces of the shells (or heads) shall be equal
to or larger than 250 mm and the inner-outer diameter ratio shall be equal to
or larger than 70 %;
2) The nozzle’s nominal diameter shall be equal to or larger than 80 mm.
b) For abutting fillet joints for nozzles and shells (or heads):
1) The curvature radius of the testing faces of the shells (or heads) shall be equal
to or larger than 150 mm;
2) The nozzle’s nominal diameter shall be equal to or larger than 100 mm.
L.2 Types of fillet joints for nozzles and shells (or heads)
Fillet joints for nozzles and shells (or heads) have the following types: inserted type,
abutting type, etc., see Figure L.1.
2) inserted type b) abutting type
Figure L.1 -- Types of fillet joints for nozzles and shells (or heads)
L.3 Probe
L.3.1 During the testing, the stable contact between the probe and the base material
shall be ensured.
L.3.2 Selection of probe
Selection of probe shall comply with the provisions as specified in 6.3.6.
L.4 Instrument adjustment
L.4.1 Incidence point and refraction angle (value K) of angle probes
Measurement of the incidence point and refraction angle (value K) of the angle probe
shall be conducted either on the CSK-I A and CSK-II A test specimens or on the RB-L
or RB-C test specimens.
L.4.2 Instrument time base
The adjustment of instrument time base shall be conducted either on the CSK-I A and
CSK-II A test specimens or on the RB-L or RB-C test specimens.
L.4.3 Distance - amplitude curve
L.4.3.1 The distance - amplitude curve shall be drawn on the CSK-II A, and the
sensitivity of the distance-amplitude curve shall comply with Table 27.
L.4.3.2 When the curvature radius of the testing faces is equal to or larger than 50 mm
~ 250 mm, the sensitivity of the distance - amplitude curve shall be calibrated on the
RB-L or RB-C test specimens. Different testing positions, changes of curvature of the
testing faces, as well as correction for changes of sonic path distance caused herein
shall be taken into consideration for this case.
a) Different welding joints on the heads or shells;
b) Different testing positions of the same welding joint (changes of deflection angle
based on the shell axis, and changes of curvature of the testing faces caused by
different positions of the nozzle on the head).
L.5 Testing
L.5.1 Testing of inserted fillet joints for nozzles and shells (or heads)
L.5.1.1 When the nozzle’s nominal diameter is equal to or larger than 250 mm and the
nozzle’s inner diameter is equal to or larger than 200 mm, the testing method of fillet
joints, the number of probes, the testing faces and the width of the probe’s moving
area shall comply with Figure N.3 and Table N.3.
L.5.1.2 When the nozzle’s nominal diameter is equal to or larger than 80 mm ~ 250
mm, the testing method of fillet joints, the number of probes, the testing faces and the
width of the probe’s moving area shall comply with Figure N.3 and Table L.1. Generally,
the testing shall be conducted according to Technology Level B.
Table L.1 -- Specific requirements for the ultrasonic testing of inserted fillet
joints for nozzles and shells (or heads)
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse
scanning by angle
probe
Number of
probes
with
different
refraction
angles
(value K)
Testing
faces
(sides)
Width of
probe
moving
area
Probe
position
Width of
probe
moving
area
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
6 ≤ t ≤ 15 1 A 1.25P — — — —
15 < t ≤ 40 1 (A or B) and F
1.25P
— — — —
6 ≤ t ≤ 15 1 (A or B) and F
1.25P
— — 1
(X & Y)
or (W &
Z)
15 < t ≤ 40 1 (A & B) and F
1.25P
d — — 1
(X & Y)
or (W &
Z)
40 < t ≤ 100 2
(A & B)
and 1.25P a b 2
(X & Y)
or (W &
Z) 1 F d
100 < t ≤
200
2 (A & B) and 0.75P a b 2
(X & Y)
and (W
& Z) 1 F d
6 ≤ t ≤ 15 1 (A or B) and F
1.25P
a b 1
(X & Y)
and (W
& Z)
15 < t ≤ 40 2 (A or B) and F
1.25P
a b 2
(X & Y)
and (W
& Z)
40 < t ≤ 100 2 (A & B) 1.25P a b 2 (X & Y)
and F d and (W
& Z)
t > 100 2 (A & B) and
0.75P
a b 2
(X & Y)
and (W
& Z)
a Testing shall, as far as possible, be conducted at position C by using straight probes.
b When the testing is conducted by using straight probes, the width of the probe’s moving area
shall be c.
L.5.2 Testing of abutting fillet joints for nozzles and shells (or heads)
L.5.2.1 When the nozzle’s nominal diameter is equal to or larger than 250 mm and the
curvature radius of the testing faces of the shell (or head) is equal to or larger than 250
mm, the testing method of fillet joints, the number of probes, the testing faces and the
width of the probe’s moving area shall comply with Figure N.5 and Table N.5.
L.5.2.2 When the nozzle’s nominal diameter is equal to or larger than 100 mm ~ 250
mm and the curvature radius of the testing faces of the shell (or head) is equal to or
larger than 150 mm, the testing method of fillet joints, the number of probes, the testing
faces and the width of the probe’s moving area shall comply with Figure L.2 and Table
L.2. Generally, the testing shall be conducted according to Technology Level B.
L.5.3 The scanning method shall, as far as possible, comply with the provisions as
specified in 6.3.9.
L.6 Flaw quantification
Flaw quantification shall comply with the provisions as specified in 6.3.13.
L.7 Flaw evaluation
Flaw evaluation shall comply with the provisions as specified in 6.3.14.
L.8 Quality classification
The quality classification of the ultrasonic testing of fillet joints for nozzles and shells
(or heads) shall comply with the provisions as specified in 6.5.1.
a) cross section b) top view
Explanation:
A, B, C, D, X, Y mean probe’s position;
a, b, c, d, x - the width of the probe’s moving area;
t - base material nominal thickness;
1 - nozzle;
2 - shell or head.
Figure L.2 -- Abutting fillet joints for nozzles and shells (or heads)
Table L.2 -- Specific requirements for the ultrasonic testing of abutting fillet
joints for nozzles and shells (or heads)
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse
scanning by angle
probe
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
(sides)
Width
of
probe
moving
area
Probe
position
Width
of
probe
moving
area
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
A 6 ≤ t ≤ 15 1 B or A 0.5P 1.25P — — — —
15 < t ≤ 40 1 B or A 0.5P 1.25P — —
6 ≤ t ≤ 15 2 B or A 0.5P 1.25P — — 1 X & Y
15 < t ≤ 40 2 B or A 0.5P 1.25P C c 1 X & Y
40 < t ≤
100
A & (B
or D)
1.25P
0.5P C c 2 X & Y
100 < t ≤
200
A & (B
or D)
0.75P
0.5P C c 2 X & Y
6 ≤ t ≤ 15 3 B or A 0.5P 1.25P C c 1 X & Y
15 < t ≤ 40 3 A & (B or D)
1.25P
0.5P C c 1 X & Y
40 < t ≤
100 3
A & B &
1.25P
0.5P C c 2 X & Y
t > 100 3 A & B & D
0.75P
0.5P C c 2 X & Y
Note 1: If testing can be conducted at position B, then the Testing conducted at position B can
replace that conducted at position A.
Note 2: When the curvature radius of the testing faces of the shells (or heads) is equal to or
larger than 150 mm ~ 250 mm, the fillet joints don’t have to take the testing by straight probes
or the testing at side D.
Annex M
(Normative)
Ultrasonic testing method of T-type welding joints
M.1 Scope
This annex is applicable to the ultrasonic testing of fully melt T-type welding joints of
pressure equipment with base material nominal thickness being 6 mm ~ 300 mm. This
annex can also be used as the reference standard for the ultrasonic testing of fully-
melt T-type welding joints for other purposes.
M.2 Types of T-type welding joints
The basic types of T-type welding joints are shown in Figure M.1.
a) L-type welding joints b) T-type welding joints
Figure M.1 -- Types of T-type welding joints
M.3 Probe
M.3.1 During the testing, the stable contact between the probe and the base material
shall be ensured.
M.3.2 Selection of probe
M.3.2.1 During the testing conducted at the outer side of the wing plate by using the
angle probe, it is recommended to use the probe with a refraction angle of 45° (K1).
During the testing conducted at the web plate by using the angle probe, the probe’s
refraction angles (value K) shall be selected based on the thickness of the web plate
and according to 6.3.6.1 and 6.3.6.2.
M.3.2.2 During the testing by using straight probe, the probe’s nominal frequency shall
be selected based on the thickness of the web plate and according to 6.3.6.3.
M.4 Instrument adjustment
M.4.1 Incidence point and refraction angle (value K) of angle probes
Measurement of the incidence point and refraction angle (value K) of the angle probe
shall be conducted on the CSK-I A, CSK-II A, CSK-III A or CSK-IV A test specimens.
M.4.2 Instrument time base
The adjustment of instrument time base shall be conducted on the CSK-I A, CSK-II A,
CSK-III A or CSK-IV A test specimens.
M.4.3 Distance-amplitude curve
The drawing of distance-amplitude curve shall comply with the provisions as specified
in 6.3.8.3, and the sensitivity of the distance-amplitude curve shall, by taking the
thickness of the web plate as the base material nominal thickness, comply with Table
27 and Table 28.
M.5 Testing
M.5.1 During the testing of T-type welding joints, the scanning method, the types and
number of probes, the testing faces as well as the width of probe’s moving area which
are selected based on different technology levels shall comply with Figure N.2 and
Table N.2.
M.5.2 During the testing of L-type welding joints, the scanning method, the types and
number of probes, the testing faces as well as the width of probe’s moving area which
are selected based on different technology levels shall comply with Figure N.4 and
Table N.4.
M.5.3 Scanning method
Scanning method shall comply with the provisions as specified in 6.3.9.
M.6 Flaw quantification
Flaw quantification shall comply with the provisions as specified in 6.3.13.
M.7 Flaw evaluation
Flaw evaluation shall comply with the provisions as specified in 6.3.14.
M.8 Quality classification
M.8.1 During the flaw evaluation, the base material nominal thickness shall be based
on the thickness of the web plate.
M.8.2 The quality classification of the ultrasonic testing of T-type welding joints shall
comply with the provisions as specified in 6.5.1.
Annex N
(Normative)
Specific requirements for the ultrasonic testing for welding joints of different
types
N.1 Flat butt joint
The specific requirements for the ultrasonic testing for flat butt joints are shown in
Figure N.1 and Table N.1.
Explanation:
A, B, C, D, E, F, G, H, W, X, Y, Z - probe position;
b - width of the probe’s moving area;
P - one full span.
Figure N.1 -- Flat butt joint
Table N.1 -- Specific requirements for the testing of flat butt joint
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe
Testing by
straight
probe
Transverse
scanning by
angle probe
Number
of probes
with
different
refraction
angles
Testing faces
(sides)
Width of
probe
moving
area
Probe
position
Number
of probes
with
different
refraction
angles
Testing
faces
(value K) (value K)
A 6 ≤ t ≤ 40 1
Single face &
double sides or
single face & single
side or double
faces & single side
1.25P — — —
6 ≤ t ≤ 40 1 Single face & double sides 1.25P — 1
Single
face
40 < t ≤
100
1 or Double faces & double sides
1.25P — 1 Single face
Single face &
double sides or
double faces &
single side
100 < t ≤
200 2
Double faces &
double sides 0.75P — 2
Single
face
6 ≤ t ≤ 15
1 or Single face & double sides
1.25P — 1 Single face 2
Single face & single
side or double
faces & single side
15 < t ≤
40 2
Double faces &
double sides 1.25P — 2
Single
face
40 < t ≤
100 2
Double faces &
double sides 1.25P
Single
side (G or
H)
2 Single face
100 < t ≤
500 2
Double faces &
double sides 0.75P
Single
side (G or
H)
2 Single face
N.2 T-type welding joint
The specific requirements for the ultrasonic testing of T-type welding joints are shown
in Figure N.2 and Table N.2.
Explanation:
A, B, C, D, E, F, G, W, X, Y, Z - probe position;
a, b, c, d, e, f, g - width of probe’s moving area;
t - base material nominal thickness;
1 - web plate;
2 - wing plate.
Figure N.2 -- T-type welding joint
Table N.2 -- Specific requirements for the ultrasonic testing of T-type welding
joints
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse scanning by
angle probe
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
(sides)
Width
of
probe
moving
area
Probe
position
Width
of
probe
moving
area
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
Width
of
probe
moving
area
6 ≤ t ≤ 15 1
(A or B)
or 1.25P — — — — —
(D & E) d + e
15 < t ≤
40 1
A or B 1.25P C c — — — (D & E) d + e
B 6 ≤ t ≤ 15 1
(A or B)
or 1.25P C c 1 F & G c
(D & E) d + e
15 < t ≤
40 1
(A & B) & 1.25P C c 1 F & G c (D & E) d + e
40 < t ≤
200
2 (A & B) & 0.75P C c 1 F & G c 1 (D & E) d + e
6 ≤ t ≤ 15 1 A & B 1.25P C c 2 F & G c
15 < t ≤
100
2 (A & B) & 1.25P
C c 2
(F & G)
& (X &
Y) & (W
& Z)
c + f +
g 1 (D & E) d + e
t > 100
3 (A & B) & 0.75P
C c 2
(F & G)
& (X &
Y) & (W
& Z)
c + f +
g 1 (D & E) d + e
N.3 Inserted fillet joints for nozzles
Specific requirements for the ultrasonic testing of inserted fillet joints for nozzles are
shown in Figure N.3 and Table N.3.
a) cross section b) top view
Explanation:
A, B, C, D, E, F, U, V, W, X, Y, Z - probe position;
a, b, c, d, e - width of the probe’s moving area;
t - base material nominal thickness;
1 - shell or head;
2 - nozzle.
Figure N.3 -- Inserted fillet joints for nozzles
Table N.3 -- Specific requirements for the ultrasonic testing of inserted fillet
joints for nozzles
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse
scanning by
angle probe
Number of
probes
with
different
refraction
angles
(value K)
Testing
faces
(sides)
Width of
probe
moving
area
Probe
position
Width of
probe
moving
area
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
6 ≤ t ≤ 15 1 A or B 1.25P C c — —
15 < t ≤ 40 1
(A or B) &
(F or D or
E)
1.25P
d or e C c
6 ≤ t ≤ 15 1 (A or B) or (D & E)
1.25P
C c 1
(X & Y)
or (W &
Z)
15 < t ≤ 40 1 (A or B) & (D & E)
1.25P
d + e C c 1
(X & Y)
or (W &
Z)
40 < t ≤
100
2 (A & B) & 1.25P
C c 2
(X & Y)
& (W &
Z) 1 (D & E) d + e
100 < t ≤
200
2 (A & B) & 0.75P
C c 2
(X & Y)
& (W &
Z) 1 (D & E) d + e
6 ≤ t ≤ 15 1 (A or B) & (D & E)
1.25P
d + e C c 1
(X & Y)
& (W &
Z)
15 < t ≤ 40 2 (A or B) & (D & E)
1.25P
d + e C c 2
(X & Y)
& (W &
Z)
40 < t ≤
100 2
(A & B) &
(D & E)
1.25P
d + e C c 2
(X & Y)
& (W &
Z)
t>100 2 (A & B) & 0.75P C c 2 (X & Y)
(D & E) d + e & (W &
Z)
Note 1: This table is applicable to the testing of fillet joints with the nozzle’s nominal diameter
equal to or larger than 250 mm and the nozzle’s inner diameter equal to or larger than 200mm.
Note 2: This table is applicable to the testing with the curvature radius of the testing face of the
shell (or head) being equal to or larger than 250 mm and the inner-outer diameter ratio being
equal to or larger than 70 %.
N.4 L-type welding joint
The specific requirements for the ultrasonic testing of L-type welding joints are shown
in Figure N.4 and Table N.4.
a) cross section b) side view
Explanation:
A, B, C, D, E, F, U, V, W, X, Y - probe position;
a, b, c - width of the probe’s moving area;
t - base material nominal thickness;
1 - nozzle or web plate;
2 - shell or head or wing plate.
Figure N.4 -- L-type welding joint
Table N.4 -- Specific requirements for the ultrasonic testing of L-type welding
joints
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse scanning by
angle probe
Number
of probes
Testing
faces
Width
of
Probe
position
Width
of
Number
of probes Testing faces
with
different
refraction
angles
(value K)
(sides) probe
moving
area
probe
moving
area
with
different
refraction
angles
(value K)
6 ≤ t ≤ 15 1 A or B or H 1.25P C c — —
15 < t ≤
40 1
A or B or
H 1.25P C c — —
6 ≤ t ≤ 15 1 A or B or H 1.25P C c 1
(D & E) or (F
& G) or (X &
Y)
15 < t ≤
40 2
(A or B) &
H 1.25P C c 2
(D & E) or (F
& G) or (X &
Y)
40 < t ≤
100 2
(H or A) &
B 1.25P C c 2 D & E
100 < t ≤
200 2
(H or A) &
B 0.75P C c 2 D & E
6 ≤ t ≤ 15 1 (H or A) & B 1.25P C c 1 D & E
15 < t ≤
40 2
(H or A) &
B 1.25P C c 1 D & E
40 < t ≤
100 3
(H or A) &
B 1.25P C c 2 D & E
t>100 3 (H or A) & B 0.75P C c 2 D & E
N.5 Abutting fillet joints for nozzles and shells (or heads)
The specific requirements for the ultrasonic testing of abutting fillet joints for nozzles
and shells (or heads) are shown in Figure N.5 and Table N.5.
a) cross section b) top view
Explanation:
A, B, C, D, X, Y - probe position;
a, b, c, d, x - width of the probe’s moving area;
t - base material nominal thickness;
1 - nozzle;
2 - shell or head.
Figure N.5 -- Abutting fillet joint for nozzles and shells (or heads)
Table N.5 -- Specific requirements for the ultrasonic testing of abutting fillet
joints for nozzles and shells (or heads)
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Testing by straight probe
Transverse
scanning by
angle probe
Number of
probes
with
different
refraction
angles
(value K)
Testing
faces
(sides)
Width of
probe
moving
area
Probe
position
Width of
probe
moving
area
Number
of probes
with
different
refraction
angles
(value K)
Testing
faces
6 ≤ t ≤ 15 1 A or B 1.25P 0.5P — — — —
15 < t ≤ 40 1 A or B 1.25P C c — —
0.5P
6 ≤ t ≤ 15 2 A or B 1.25P 0.5P — — 1 X & Y
15 < t ≤ 40 2 A or B 1.25P 0.5P C c 1 X & Y
40 < t ≤
100 2
A & (B or
D)
1.25P
0.5P C c 2 X & Y
100 < t ≤
200 2
A & (B or
D)
0.75P
0.5P C c 2 X & Y
6 ≤ t ≤ 15 3 A or B 1.25P 0.5P C c 1 X & Y
15 < t ≤ 40 3 A & (B or D)
1.25P
0.5P C c 1 X & Y
40 < t ≤
100 3 A & B & D
1.25P
0.5P C c 2 X & Y
t>100 3 A & B & D 0.75P 0.5P C c 2 X & Y
Note 1: This table is applicable to the testing of fillet joints with the nozzle’s nominal diameter
equal to or larger than 250 mm.
Note 2: This table is applicable to the testing with the curvature radius of the testing face of the
shell (or head) being equal to or larger than 250 mm.
N.6 Cross welding joint
The specific requirements for the ultrasonic testing of the cross-welding joint are shown
in Figure N.6 and Table N.6.
Explanation:
A, B, C, D, E, F, G, H, W, W1, W2, X, X1, X2, Y, Y1, Y2 - probe position;
a, b, c, d, e, f, g, h - width of probe’s moving area;
t - base material nominal thickness;
1, 2, 3 - components
Figure N.6 -- Cross welding joint
Table N.6 -- Specific requirements for the ultrasonic testing of cross welding
joints
Testing
technology
level
Base
material
nominal
thickness
t/mm
Testing of longitudinal flaws Testing of transverse flaws
Testing by angle probe Transverse scanning by angle probe
Number of
probes
with
different
refraction
angles
(value K)
Testing faces
(sides)
Width of
probe
moving
area
Number of
probes
with
different
refraction
angles
(value K)
Testing faces
A 6 ≤ t ≤ 15 1
(A & C) or (B &
D) 1.25P — —
15 < t ≤ 40 1 A & B & C & D 0.75P — —
6 ≤ t ≤ 15 1 A & B & C & D 1.25P 1
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
15 < t ≤ 40 2 A & B & C & D 0.75P 1
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
40 < t ≤
200
(A & B & C & D)
& (E & F & G &
H)
0.75P
e + f + g
+ h
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
6 ≤ t ≤ 15 1 A & B & C & D 1.25P 1
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
15 < t ≤ 40 2 A & B & C & D & (E & F & G & H)
0.75P
e + f + g
+ h
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
40 < t ≤
100
(A & B & C & D)
& (E & F & G &
H)
0.75P
e + f + g
+ h
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
t > 100 3 1
(A & B & C & D)
& (E & F & G &
H)
0.75P
e + f + g
+ h
(X1 & Y1 & W1 &
Z1) & (X2 & Y2 &
W2 & Z2)
N.7 Inserted butt joints for nozzles and shells (or heads)
The specific requirements for the ultrasonic testing of inserted butt joints for nozzles
and shells (or heads) are shown in Figure N.7 and Table N.7.
Explanation:
A, B, C, D, E, F, G, H, W, X, Y, Z - probe position;
b - width of probe’s moving area;
1 - shell or head;
2 - nozzle.
Figure N.7 -- Inserted butt joint for nozzle and shell (head)
Table N.7 -- Specific requirements for the ultrasonic testing of inserted butt
joints for nozzles and shells (heads)
Testing
technology
level
Base material
nominal
thickness
t/mm
Testing of longitudinal flaws
Testing of
transverse
flaws
Testing by angle probe
Testing by
straight
probe
Transverse scanning by
angle probe
Number of
probes
with
different
refraction
angles
(value K)
Testing
faces
Width
of
probe
moving
area
Probe
position
Number of
probes with
different
refraction
angles
(value K)
Testing
faces
A 6 ≤ t ≤ 40 1 A or B 1.25P — — —
6 ≤ t ≤ 40 1 or A & B 1.25P — 1 (X & Y) or (W & Z) 2 A or B 1.25P —
40 < t ≤ 100 2 A & B 1.25P 1 (X & Y) or (W & Z)
100 < t ≤ 200 2 A & B 0.75P — 2 (C & D) or (E & F)
6 ≤ t ≤ 15 1 or A & B 1.25P — 1 (C & D) or (E & F) 2 A or B 1.25P —
15 < t ≤ 40 2 A & B 1.25P — 2 (C & D) or (E & F)
40 < t ≤ 100 3 A & B 1.25P (G or H) 2 (C & D) or (E & F)
t > 100 3 A & B 0.75P (G or H) 2 (C & D) or (E & F)
Note 1: This table is applicable to the testing with the curvature radius of the testing face of the
shell (or head) being equal to or larger than 250 mm and the inner-outer diameter ratio equal
to or larger than 70 %
Note 2: During the testing of face B, if the width of one or several probe’s moving area is
enough, we shall preferentially choose this kind of probe to conduct the testing at both sides
of face B.
Annex O
(Normative)
CSK-III A Test specimen
O.1 Shape and dimension of CSK-III A test specimen shown in Figure O.1.
Note: The dimension error shall not exceed ±0.05 mm.
Figure O.1 -- CSK-III A test specimen
O.2 Selection of sensitivity of the distance-amplitude curve
For welding joints with the base material nominal thickness being 8 mm ~ 120 mm, the
sensitivity of the distance - amplitude curve, during the testing by the angle probe, shall
comply with Table O.1.
Table O.1 -- Sensitivity of the distance - amplitude curve during the testing by
angle probes (recommended)
Type of test
specimen
Base material
nominal thickness
t/mm
Evaluation line Scale line Rejection line
CSK-III A
8 ~ 15
> 15 ~ 40
> 40 ~ 120
Φ1 × 6 - 12 dB
Φ1 × 6 - 9 dB
Φ1 × 6 - 6 dB
Φ1 × 6 - 6 dB
Φ1 × 6 - 3 dB
Φ1 × 6
Φ1 × 6 + 2 dB
Φ1 × 6 + 5 dB
Φ1 × 6 + 10 dB
7- 1 × 6 short cross bore
The rest
Annex P
(Normative)
Determination of the loss difference during sound energy transmission
P.1 General
P.1.1 The main factor for the base material itself affecting the reflected wave amplitude
is that the texture attenuation, rough surface of the base materials or coupling status
of the curved surface cause losses of sound energy.
P.1.2 The texture attenuation of carbon steel or low alloy steel plates can be ignored
when the frequency is lower than 2.5 MHz and the sonic path distance does not exceed
200 mm, or the attenuation coefficient is less than 0.01 dB/mm.
P.1.3 During the testing, if the sonic path distance is long or the texture attenuation
coefficient exceeds the above scope, we shall consider the texture attenuation
correction when determining the flaw amplitude. If the surface roughness degree of
the base material is very high or the base material has curved surface, we shall also
consider the sound energy loss of the surface.
P.2 Measurement of ultrasonic texture attenuation during the testing by angle
probes
Figure P.1 -- Determination of ultrasonic texture attenuation
P.2.1 Place two probes with the same size, nominal frequency and refraction angle
(value K) at the intact positions of the base material to be tested as shown in Figure
P.1. The distance between the two probes’ incidence points is 1P, put the instrument
in pitch-catch state, find the maximum reflected wave amplitude and record the
amplitude value H1 (dB).
P.2.2 Move the two probes to make the distance between them be 2P, find the
maximum reflected wave amplitude and record the amplitude value H2 (dB).
P.2.3 The attenuation coefficient of the single sonic path distance can be calculated
according to formulas (P.1) ~ (P.3):
where:
∆ - The amplitude difference caused during the spread of......
Related standard:   NB/T 47013.10-2015  NB/T 47013.11-2015
   
 
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