GB/T 34370.6-2017 PDF English
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Nondestructive testing of amusement equipment -- Part 6: Radiographic testing
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GB/T 34370.6-2017: PDF in English (GBT 34370.6-2017) GB/T 34370.6-2017
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 97.200.40
Y 57
Nondestructive testing of amusement equipment -
Part 6: Radiographic testing
ISSUED ON: SEPTEMBER 29, 2017
IMPLEMENTED ON: APRIL 01, 2018
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 4
1 Scope ... 5
2 Normative references ... 5
3 Terms and definitions ... 6
4 Method summary ... 7
5 Safety requirements ... 8
6 Personnel requirement ... 8
7 Testing equipment and apparatus ... 8
8 Testing process specification ... 10
9 Testing ... 12
10 Quality grading of radiographic testing of steel fusion welded butt joints .. 23
11 Quality grading of radiographic testing of fusion welded girth butt joint of steel
pipe fittings ... 25
12 Radiographic testing report ... 28
Appendix A (Informative) Schematic diagrams of typical penetration methods
... 30
Appendix B (Informative) Method for determining the number of penetrations
for girth butt welded joints ... 32
Appendix C (Normative) Calculation method of focus size ... 37
Appendix D (Normative) Type and specification of special image quality
indicator ... 38
Appendix E (Normative) Placement position of overlap mark ... 39
Appendix F (Normative) Type and specification of reference blocks ... 40
Nondestructive testing of amusement equipment -
Part 6: Radiographic testing
1 Scope
This Part of GB/T 34370 specifies the X-ray and γ-ray testing techniques and
quality grading requirements for the fusion welded butt joints of amusement
equipment.
This Part applies to the radiographic testing of carbon steel, low alloy steel, and
stainless steel butt welded joints of amusement equipment with a thickness of
2 mm~200 mm.
2 Normative references
The following documents are indispensable for the application of this document.
For the dated references, only the editions with the dates indicated are
applicable to this document. For the undated references, the latest edition
(including all the amendments) are applicable to this document.
GB/T 11533 Standard for logarithmic visual acuity charts
GB/T 12604.2 Non-destructive testing - Terminology - Terms used in
radiographic testing
GB 18871 Basic standards for protection against ionizing radiation and for
the safety of radiation sources
GB/T 19348.1 Non-destructive testing - Industrial radiographic film - Part 1:
Classification of film systems for industrial radiography
GB/T 19348.2 Non-destructive testing - Industrial radiographic films - Part 2:
Control of film processing by means of reference values
GB/T 19802 Non-destructive testing - Industrial radiographic illuminators -
Minimum requirements
GB/T 20306 Amusement devices terminology
GB/T 20737 Non-destructive testing - General terms and definitions
5 Safety requirements
The safety requirements during the testing process include at least:
a) The testing personnel shall comply with the safety requirements of the site
of the piece under test; according to the requirements of the location of
testing, wear protective overalls and wear relevant protective equipment.
b) After the amusement equipment are in operation, the testing is carried out.
It shall pay attention to the temperature state of the piece under test, to
avoid scalds.
c) Radiological protection shall comply with the relevant provisions of GB
18871, GBZ 117, and GBZ 132.
d) When performing X-ray testing on site, it shall, according to the provisions
of GBZ 117, delimit the control zone and management zone and set
warning signs. The testing staff shall wear a personal dosimeter and carry
a dose alarm.
e) When performing γ-ray testing on site, it shall, according to the provisions
of GBZ 132, delimit the control zone and supervision zone and set warning
signs. When testing, around the boundary of the control zone, the
radiation level shall be measured. The testing staff shall wear a personal
dosimeter and carry a dose alarm.
f) This Clause does not list all the safety requirements for testing. Users using
this Part shall, before testing, establish safety criteria.
6 Personnel requirement
Personnel engaged in radiographic testing, in addition to complying with the
relevant provisions of GB/T 34370.1, before taking up the post, shall receive a
training of radiation safety knowledge and obtain a radiation staff certificate.
The uncorrected or corrected near (distance) visual acuity and distant (distance)
visual acuity of the radiographic testing personnel shall not be less than 5.0
(The decimal is recorded as 1.0). The test method shall comply with the
provisions of GB/T 11533. The personnel engaged in film evaluation shall, every
12 months, have an examination of visual acuity.
7 Testing equipment and apparatus
7.1 Imaging system
f) Information of the piece under test: Name, number, specification, material,
groove type, welding method, heat treatment condition;
g) Schematic diagram of penetrated position of object;
h) Penetration specifications: Technical grade, penetration arrangement, film,
intensifying screen, ray energy, exposure, focal distance, darkroom
disposal methods and conditions, etc.;
i) Testing timing;
j) Testing process and data analysis and explanation;
k) Evaluation and grading of testing results;
l) Testing records, report format;
m) Data archiving;
n) Signatures of developers (level), reviewers (level), and approvers and
date.
8.2 Testing process card
For each piece under test, based on the instruments used and the actual
situation on site, in accordance with GB/T 34370.1, this Part, and the general
testing process specification, the radiographic testing process card shall be
developed, to determine the testing position and implementation conditions,
such as the penetrated position of the object, the installation position of the
source, and surface conditions. Each piece under test shall be surveyed and
mapped. DRAW the schematic diagram of the structure of the piece under test
and the schematic diagram of penetrated position.
The method and position of the penetration shall be determined to ensure that
the part under test of the object is fully tested.
In the manufacture and installation of amusement equipment and the use of
radiographic testing, the testing timing and sampling rate shall be selected in
accordance with the requirements and principles of regulations, product
standards, and relevant technical documents.
The content of testing process card shall include at least:
a) Process card number;
b) Executive standard for testing and quality grade requirement;
d) Other information: Documentation of maintenance, repairs, and
transformations, etc.
9.1.2 On-site survey
The site of the piece under test shall be surveyed, to find out all the factors
which may affect the testing, such as surface conditions, structural style, etc.
During testing, interference of these factors shall be avoided as much as
possible.
9.1.3 Development of testing process card
Perform according to 8.2.
9.1.4 Surface requirements
Before radiographic testing, the surface of butt welded joint shall be visually
tested and be qualified. The image on the film of the irregular state of the
surface shall not obscure or interfere with the flaw image, otherwise the surface
shall be properly trimmed.
9.1.5 Testing timing
Unless otherwise specified, the radiographic testing shall be carried out after
the completion of welding. For materials with a tendency to delayed crack, at
least 24 h after the welding is completed, radiographic testing is carried out.
9.2 Penetration arrangement
9.2.1 Penetration method
According to the characteristics of the object and the requirements of the
technical conditions, the appropriate penetration method shall be selected.
Where it can be implemented, single-wall penetration method shall be used.
When single-wall penetration is not possible, double-wall penetration is allowed.
For typical penetration methods, see Appendix A.
9.2.2 Penetration direction
During penetration, the center of the bundle of rays shall generally point
vertically to the center of the penetration zone. If necessary, a direction which
facilitates the discovery of flaws may be selected for penetration.
9.2.3 Every penetrated length
Every penetrated length is controlled by the ratio of max. and min. penetrated
thickness, K. The ratio of max. and min. penetrated thickness of different types
When elliptical-imaging, the opening width of the image (the maximum spacing
of the upper and lower weld projections) shall be controlled to be about 1 times
the weld width.
For small-diameter tubes with nominal diameter De≤80 mm and wall thickness
T≤6 mm, when multiple times of penetration cannot be carried out due to
structural reasons, with the consent of the parties to the contract, elliptical
imaging or overlapping imaging method may be adopted for a penetration. At
this time, effective measures shall be taken to expand the detectable range of
flaws, and to ensure that the blackness and sensitivity within the film evaluation
scope meet the requirements.
9.3 Ray energy
9.3.1 The X-ray radiography shall use the lower tube voltage as much as
possible. When using a higher tube voltage, a proper exposure shall be
guaranteed. The maximum X-ray tube voltage allowed for different penetrated
thicknesses of steel shall be determined according to the instrument
manufacturer’s recommended values.
For objects with large variations in section thickness, with the consent of the
parties to the contract, it is allowed to use the X-ray tube voltages in excess of
those recommended by the manufacturer. For steel, the maximum shall not
exceed 50 kV.
9.3.2 The penetrated thickness range applicable to the γ-ray source shall
comply with the requirements of Table 3.
With the consent of the parties to the contract, under the premise of taking
effective compensation measures and ensuring that the sensitivity of image
quality indicator meets 9.12.3, the minimum penetrated thickness of the Ir192
source may be reduced to 10 mm; the minimum penetrated thickness of the
Se75 source may be reduced to 5 mm.
Table 3 -- γ-ray penetrated thickness range of steel (in millimeters)
9.4 Minimum distance from the source to the object surface
9.4.1 The distance f from the selected source to the object surface shall meet
the requirement of the following formula:
Source Penetrated thickness W
9.5.1 For X-ray radiography, when the focal distance is 700 mm, the
recommended value of exposure is not less than 15 mA • min. When the focal
distance changes, according to the inverse-square law, the exposure may be
converted.
9.5.2 When using γ-ray source to penetrate, the total exposure time shall be at
least not less than 10 times the time required to deliver the source back and
forth.
9.6 Exposure curve
9.6.1 For each in-use X-ray equipment, the exposure curve of materials
commonly used in amusement equipment shall be made. According to the
exposure curve, the exposure parameters are determined.
9.6.2 Conditions such as film, intensifying screen, focal distance, ray energy
used to make the exposure curve and parameters such as sensitivity and
blackness that the film shall reach shall comply with the provisions of this Part.
9.6.3 The in-use exposure curve shall be checked at least once a year. After
the important parts of the ray equipment are replaced or after major repairs, the
exposure curve shall be checked or re-made in time.
9.6.4 When using a γ-ray source, an exposure guide rule or the like may be
used to calculate the exposure time.
9.7 Unwanted ray and scattered ray shielding
9.7.1 Appropriate measures such as metal intensifying screens, lead plates,
filters, and collimators shall be used to shield the scattered rays and unwanted
rays, to limit the range of irradiation field.
9.7.2 For the testing process developed for the first time, or the conditions and
environment of the testing process change, when the testing process is applied
to the formal testing, it shall be subjected to backscatter protection check.
The method of checking the backscatter protection is to attach the “B” type mark
on the back of the cassette. Generally, the height of the “B” type is 13 mm; the
thickness is 1.6 mm. According to the provisions of testing process, penetration
and darkroom disposal are carried out. If a “B” image with a blackness lower
than the surrounding background blackness appears on the film, it indicates
that the backscatter protection is insufficient; the thickness of the backscatter
protection lead plate shall be increased. If the “B” image does not appear on
the film, or a “B” image with a blackness higher than the surrounding
background blackness appears, it indicates that the backscatter protection is
satisfactory.
9.8.4 The small-diameter tube may select the ordinary wire-type image quality
indicator or the special (equal-diameter wire) image quality indicator specified
in Appendix D. The wire shall be placed across the weld. The image quality
indicator shall be placed on the source side. When it cannot be placed on the
source side, it may be placed on the film side.
9.8.5 On the film, when a continuous wire image having a length of not less
than 10 mm is clearly visible in the blackness uniformity area (generally a base
metal area adjacent to the weld), the wire is considered to be identifiable. A
dedicated image quality indicator shall be able to identify no less than two wires.
9.9 Marking
9.9.1 The marks of the penetrated position are composed of an identification
mark and a positioning mark. Marks are generally constructed of appropriate-
sized numbers, pinyin letters, and symbols made of lead (or other suitable
heavy metals).
9.9.2 The identification mark generally includes identification of manufacturing
organization (and/or testing organization), product number, welded joint number,
position number, and penetration date. The penetration after rework shall also
have a rework mark. The penetration of the expanded testing ratio shall also
have a mark for expanded testing.
9.9.3 The positioning mark generally includes a center mark and an overlap
mark. The center mark indicates the center position of the penetrated position
section and the direction of the segment number, is generally indicated by a
cross arrow “ ”. The overlap mark is a penetration segment mark for
continuous testing, may be indicated by the symbol “↑” or other methods
capable of displaying the overlap situation.
9.9.4 Marks shall generally be placed at least 5 mm from the edge of the weld.
The position where the overlap mark is placed shall also comply with Appendix
E. All marked images shall not overlap and shall not interfere with images within
the effective evaluation scope.
9.10 Film processing
9.10.1 It may be handled by automatic processor or manual processing. It is
recommended to use automatic processor.
9.10.2 Film processing shall generally be carried out in accordance with the
specifications of the film instruction manual.
9.11 Film evaluation requirements
In accordance with the requirements of the testing process specification, the
testing data and related information shall be recorded. In addition, it shall
include at least the contents of 8.2 and Clause 12.
10 Quality grading of radiographic testing of steel
fusion welded butt joints
10.1 Quality grading conditions
This clause applies to the quality grading of radiographic testing of fusion
welded butt joints of carbon steel, low alloy steel, and austenitic stainless steel
with a thickness of 2 mm~200 mm.
10.2 Flaw type
The flaws in the welded joint, according to their properties, are classified into
five types: crack, incomplete fusion, incomplete penetration, stripy flaw, and
round flaw.
10.3 Division of quality grade
According to the properties, quantity, and intensity of the flaws existing in the
welded joint, the quality grade of welded joint is divided into I, II, III, and IV
grades.
10.4 General provisions on quality grading
10.4.1 Cracks, incomplete fusion, incomplete penetration, and stripy flaws are
not allowed in Grade I welded joints.
10.4.2 Cracks, incomplete fusion, and incomplete penetration are not allowed
in Grades II and III welded joints.
10.4.3 The welded joint with flaws exceeding Grade III is Grade IV.
10.4.4 When the quality grade of each type of flaw evaluation is different, the
grade with the worst quality is used as the quality grade of the welded joint.
10.5 Grading evaluation of round flaws
10.5.1 Round flaws, using the evaluation area, is evaluated for quality grading.
The flaw evaluation area is a rectangle parallel to the weld. Its dimensions are
shown in Table 7. The flaw evaluation area shall be selected in the area with
the most serious flaws.
11.2 Flaw type
The flaws in the welded joint, according to their properties, are classified into
seven types: crack, incomplete fusion, incomplete penetration, stripy flaw,
round flaw, root concavity, and root undercut.
11.3 Division of quality grade
According to the properties, quantity, and intensity of the flaws existing in the
welded joint, the quality grade of welded joint is divided into I, II, III, and IV
grades.
11.4 General provisions on quality grading
11.4.1 Cracks, incomplete fusion, incomplete penetration, stripy flaws, root
concavity, and root undercut are not allowed in Grade I welded joints.
11.4.2 Cracks, incomplete fusion, double-sided welding, and incomplete
penetration in one-sided welding with backing plate are not allowed in Grades
II and III welded joints.
11.4.3 The welded joint with flaws exceeding Grade III is Grade IV.
11.4.4 When the quality grade of each type of flaw evaluation is different, the
grade with the worst quality is used as the quality grade of the welded joint.
11.5 Grading evaluation of round flaws
In accordance with 10.5, quality grading is evaluated. However, for the De≤100
mm small-diameter tube flaw evaluation area, TAKE 10 mm×10 mm.
11.6 Grading evaluation of stripy flaws
In accordance with 10.6, quality grading is evaluated.
11.7 Grading evaluation of incomplete penetration flaws of one-sided
welding without backing plate
When the tube’s nominal diameter De is >100 mm, the quality grading of
incomplete penetration flaws of one-sided welding without backing plate is
evaluated according to Table 12. The incomplete penetration flaws of the one-
sided welding without backing plate of the small-diameter tube with a tube
nominal diameter De≤100 mm, according to the provisions of Table 13, are
evaluated for quality grading. The depth of incomplete penetration shall be
determined using the special reference block for incomplete penetration
specified in Appendix F. When measuring, the special reference block for
Appendix B
(Informative)
Method for determining the number of penetrations for girth butt welded
joints
B.1 Graph for the number of penetrations
For the 100% testing of the butt girth welded joint with a nominal diameter
De>100 mm, the minimum number of penetrations required is related to the
penetration method and the ratio of max. and min. penetrated thickness. This
value can be found directly from Figure B.1~Figure B.4.
a) Figure B.1 is a graph for the number of penetrations with ratio of max. and
min. penetrated thickness K=1.1, for single-wall penetration with the
source outside for butt girth welded joint;
b) Figure B.2 is a graph for the number of penetrations with ratio of max. and
min. penetrated thickness K=1.1, for penetrating butt girth welded joint
using other methods (eccentric inner-penetration method and double-wall
single-image method);
c) Figure B.3 is a graph for the number of penetrations with ratio of max. and
min. penetrated thickness K=1.2, for single-wall penetration with the
source outside for butt girth welded joint;
d) Figure B.4 is a graph for the number of penetrations with ratio of max. and
min. penetrated thickness K=1.2, for penetrating butt girth welded joint
using other methods (eccentric inner-penetration method and double-wall
single-image method).
B.2 Method for determining the number of penetrations by the graph
The steps of determining the number of penetrations from the graph are:
Calculate T/De, De/f; on the abscissa, FIND the point corresponding to the T/De
value; DRAW a straight line perpendicular to the abscissa through this point; on
the ordinate, FIND the point corresponding to De/f; DRAW a straight line
perpendicular to the ordinate through this point; from the region where the
intersection of the two straight lines is located, determine the required number
of penetrations. When the intersection is on the boundary between the two
regions, a larger value shall be taken as the minimum number of penetrations
required.
......
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.
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