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GB/T 16508.4-2013 (GB/T16508.4-2013)

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GB/T 16508.4-2013English150 Add to Cart 0--3 minutes. Auto-delivery. Shell boilers -- Part 4: Fabrication, inspection and acceptance Valid


GB/T 16508.4-2013: PDF in English (GBT 16508.4-2013)
GB/T 16508.4-2013
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
ICS 27.060.30
J 98
Partially replacing GB/T 16507-1996
Shell Boilers -- Part 4: Fabrication, Inspection and
Acceptance
ISSUED ON: DECEMBER 31, 2013
IMPLEMENTED ON: JULY 1, 2014
Issued by: General Administration of Quality Supervision, Inspection and
Quarantine of the PRC;
Standardization Administration of the PRC.
Table of Contents
Foreword ... 3
1 Scope ... 6
2 Normative References ... 6
3 Terms and Definitions ... 7
4 Fabrication ... 8
5 Inspection and Test ... 33
6 Delivery Information and Nameplate ... 41
Appendix A (Normative) Welded Tube Orifice of Boiler ... 44
Foreword
GB/T 16508 Shell Boilers comprises the following eight parts:
-- Part 1: General Requirements;
-- Part 2: Material;
-- Part 3: Design and Strength Calculation;
-- Part 4: Fabrication, Inspection and Acceptance;
-- Part 5: Safety Appurtenances and Instruments;
-- Part 6: Combustion Systems;
-- Part 7: Installation;
-- Part 8: Operation.
This Part is Part 4 of GB/T 16508.
This Part was drafted according to the rules given in GB/T 1.1-2009.
This Part replaces the relevant contents such as fabrication, inspection, and
acceptance in GB/T 16507-1996 Rules for Construction of Stationary Boilers.
Compared with GB/T 16507-1996, the main technical changes are as follows:
a) ADD Chapter 3 "Terms and Definitions";
b) Chapter 4:
-- ADD management requirements for the use of new process, new technique,
and new method;
-- ADD requirements for butt welds of flat tube plate and arched tube plate;
-- ADD requirements for dimension deviation of corrugated furnace;
-- ADD requirements for dimension deviation of tube orifice center distance and
dimension deviation of tube orifice;
-- ADD forming requirements of threaded flue;
Shell Boilers -- Part 4: Fabrication, Inspection and
Acceptance
1 Scope
This Part of GB/T 16508 specifies the requirements for fabrication, inspection and test,
delivery information and nameplate of stationary shell boilers.
This Part is applicable to the shell boilers defined within the scope of GB/T 16508.1.
2 Normative References
The following referenced documents are indispensable for the application of this
document. For dated reference, only the edition cited applies. For undated reference,
the latest edition of the normative document (including any amendments) applies.
GB 146.1 Rolling Stock Gauge for Standard Gauge Railways
GB 191 Packaging - Pictorial Marking for Handling of Goods
GB/T 1804 General Tolerances - Tolerances for Linear and Angular Dimensions without Individual Tolerance Indications
GB/T 2652 Tensile Test Methods on Weld and Deposited Metal
GB/T 16507.5 Water-Tube Boilers - Part 5: Fabrication
GB/T 16508.1 Shell Boilers - Part 1: General Requirements
GB/T 16508.2 Shell Boilers - Part 2: Material
GB/T 16508.3 Shell Boilers - Part 3: Design and Strength Calculation
GB/T 19293 Method of X-Ray Radioscopy for Butt-Weld
GB/T 25198 Heads for Pressure Vessels
4 Fabrication
4.1 Basic requirements
4.1.1 Qualifications of boiler fabrication organization and operation personnel shall
meet those specified in GB/T 16508.1.
4.1.2 Materials for boiler fabrication shall meet the requirements of design document
and GB/T 16508.2.
4.1.3 Fabrication, inspection and acceptance of boilers shall meet the requirements
of TSG G0001 Boiler Safety Technical Supervision Administration Regulation, design
documents and this Part.
4.1.4 Adoption of new process, new technique and new method for boiler fabrication
and inspection unlisted in this Part shall be in accordance with relevant provisions of
TSG G0001 Boiler Safety Technical Supervision Administration Regulation.
4.2 Mark and mark transplantation
4.2.1 Material marks for pressure parts and main loaded non-pressure parts
(hanger/support and brace) shall have traceability. In the process of fabrication, if the
original mark is cut off or the material is divided into several pieces, the fabrication
organization shall specify the expression mode of the mark and complete mark
transplantation prior to the material cutting.
4.2.2 Weld of pressure part, weld of product welding specimen and surrounding fillet
weld between the pressure parts and the main loaded non-pressure parts shall be
printed with steel seal of welder code, or the welder code shall be recorded in the
welding record including weld map.
4.2.3 Non-destructive testing mark shall meet the requirements of NB/T 47013 (JB/T
4730).
4.2.4 In the area of inner and outer arcs of tube bend, hard imprint mark is not allowed
to be used.
4.3 Material cutting
4.3.1 Material cutting method is selected according to steel characteristics and
specification. The adopted cutting method shall ensure machining precision.
4.3.2 During thermal cutting, the material may be pre-heated according to the type
flange/boiler furnace hole flange on the tube plate to the starting point of the flange
bending is greater than 5mm may be polished or soldered according to 4.4.2.2.
4.4.2.4 Any crack and rip due to unsatisfied steel plate quality and over-burning, shall
not be subjected to repair welding.
4.4.3 Weld layout
4.4.3.1 The longitudinal welds of two adjacent shell sections at the shell (except that
with unequal wall thickness), shell and boiler furnace as well as the butt welds at the
head, tube plate, boiler furnace top or foot ring and the longitudinal weld at adjacent
shell sections shall not be connected with each other. The distance between the
centerlines of the welds (arc length of the excircle) is at least three times the thickness
of the thicker steel plate and greater than or equal to 100mm.
4.4.3.2 The distance (L) between centerlines of the butt welds at the boiler heating
surface tube (except the dissimilar steel joint) and the straight section of the tubing
shall meet the following requirements:
a) The outside diameter is less than 159mm and L is greater than or equal to 2
times of the outside diameter;
b) The outside diameter is greater than or equal to 159mm and L is greater than
or equal to 300mm.
Where the boiler structure is difficult to meet the requirements of this article, the heat-
affected zone of butt welds shall not be overlapped, and L shall be greater than or
equal to 50mm.
4.4.3.3 Boiler heating surface tube and tubing butt weld position shall meet the
following requirements:
a) The butt weld at the heating surface tube and tubing (except coil tube and
molded tube fittings) shall be located at the straight section of the tube;
b) The distance between the centerline of the butt weld at the heating surface tube
and the external wall of the shell and header, starting point of the tube bending
and the edges of the tube supports and hangers is at least 50mm; for boilers
with rated operating pressure of greater than or equal to 3.8MPa, the distance
is at least 70mm and that for the tubing shall not be less than 100mm.
4.4.3.4 Main welds at the pressure parts and the neighboring areas shall be kept
clear of the welded attachments. If impossible, the weld at the welded attachments
may be penetrated through the main weld, but shall not be ended at the main weld and
the neighboring areas.
4.4.3.5 Tube orifices in expansion connection shall not be arranged at the
longitudinal weld of the shell and also shall avoid being arranged at the circumferential
weld as much as possible.
4.4.3.6 The orifice of common down-comer shall not be made at the weld, and other
welded tube orifices also shall avoid being made at the weld and its heat-affected zone.
4.4.3.7 For the shell with nominal inside diameter of greater than 1800mm, quantity
of longitudinal butt welds at each section of the shell shall not be greater than 3 pieces;
for the shell and boiler furnace with the nominal inside diameter of not greater than
1800mm; quantity of longitudinal butt welds at each section of the shell shall not be
greater than 2. Arc length of the excircle between the longitudinal welds at each section
of the shell shall not be less than 300mm.
4.4.3.8 During shell splicing, length of any shell section at the shell and the boiler
furnace shall not be less than 300mm and that of any shell section at the header shell
shall not be less than 500mm.
4.4.3.9 Quantity of butt welds at the tube sheet and head with the nominal inside
diameter of greater than 2200mm shall not be greater than 2; that of the butt welds at
the tube sheet and head with the nominal diameter of not greater than 2200mm shall
not be greater than 1.
4.4.3.10 The distance from the butt weld of the head to the centerline of the head
shall not be greater than 30% of the nominal bore of the end, furthermore, the weld
shall not pass through the flange manhole or arranged on the circular arc of the plate
edge of manhole.
4.4.3.11 The whole piece of the butt weld of the flat tube plate shall not be arranged
at the flange arc, or penetrate through the flange hole.
4.4.3.12 Distance from the butt weld of the arched tube plate to the intersecting line
of the straight part and the raised part shall not exceed 30% of equivalent inside
diameter (centerline is counted from that of edge flue row).
4.4.3.13 The butt weld of the foot ring shall be arranged in radial direction, the
minimum excircle arc length between centerlines of two welds shall not be less than
300mm.
4.4.4 Groove preparation
4.4.4.1 The groove type, dimension and assembling gap of welded joints shall meet
4.6 Welding
4.6.1 General requirements
4.6.1.1 The welder shall conduct welding as per welding procedure specification
prepared according to welding procedure that passes the evaluation and make the
welding record well.
4.6.1.2 Welding procedure qualification other than this Organization shall not be used
for welding work of pressure part products of this Organization.
4.6.1.3 The fabrication organization shall create technical files of welders, and
inspect and evaluate the actual welding procedure parameters and weld quality as well
as the welder's conformity with the procedure discipline.
4.6.2 Pre-welding preparation and welding environment
4.6.2.1 The storage house for electrodes, welding fluxes and other welding materials
shall be kept dry, and its relative humidity shall not be greater than 60%.
4.6.2.2 Without effective protection measures, the welding must not be conducted
under one of the following welding environments:
a) Wind speed is greater than 10m/s at shielded metal arc welding;
b) Wind speed is greater than 2m/s at gas metal arc welding (GMAW);
c) The relative humidity is greater than 90%;
d) Rain and snow environment;
e) The weldment temperature is lower than -20°C.
4.6.2.3 Where the weldment temperature is -20°C~0°C, the weldment shall be
preheated to 15°C above within 100mm of the initial welding.
4.6.3 Welding procedure qualification
4.6.3.1 Before welding of the boiler product, the following welded joints shall be
subjected to welding procedure qualification:
a) Butt welded joint between pressure parts;
b) Full-penetration T-shaped joint or fillet joint between the pressure parts or
structure that exceeds the limit, another heat treatment is allowed to be
conducted for the inspected specimen and then double specimen are taken for
the re-inspection (after the qualification, the mechanical property still shall be
re-inspected) and all the specimens may be deemed as acceptable after they
pass the re-inspection.
4.6.3.4 Welding procedure qualification document shall meet the following
requirements:
a) The welding organization shall, according to the product welding requirements
and welding procedure qualification standard, prepare preliminary welding
procedure specification (PWPS) for evaluation and form a welding procedure
qualification report (PQR) after the qualification in the welding procedure
qualification and may carry out welding after formulating the welding procedure
specification (WPS);
b) Welding procedure specification shall at least include welding method and
degree of mechanization, material, thickness range, welding groove, welding
specification, welding position, preheating temperature, number of welding
layers (number of beads), welding material, heat treatment requirements and
welding technical requirements etc.;
c) After completion of the welding procedure qualification, the welding procedure
qualification report and welding procedure specification shall be approved by
the welding engineer from the fabrication organization and may be kept in the
technical files after the approval by the technical principal. The technical files
shall be kept until the procedure qualification is invalid. The welding procedure
qualification specimen shall be at least kept for 5 years. Upon approval, the
technical contents of welding procedure qualification shall not be modified and
only editorial modification and supplement are allowed.
4.6.4 Welding procedure
4.6.4.1 No arc ignition is allowed on non-welded surface of the weldment; any crater,
if any, shall be polished or soldered. For materials with crack tendency, surface non-
destructive testing shall be carried out after polishing or soldering.
4.6.4.2 Run-on plate, run-off plate or product welding specimen on both ends of the
longitudinal weld of the weldment must not be dismantled by hammering.
4.6.4.3 During assembling, the weldment shall not be aligned in a forced way. The
welding may be carried out only after the weldment assembling and tack welding
quality meet the requirements of the procedure documents.
d) Where combined welding procedure is adopted, if preheating is required,
preheating requirements shall be determined for each procedure respectively;
e) The temperature of the weldment joint requiring preheating shall not be less
than the preheating temperature in the whole process of welding.
4.6.5.2 Post-heating shall meet the following requirements:
a) Post-heating measures shall be taken for the low alloy steel with relatively large
sensitivity to cold crack and the weldment with larger restraint degree, which
shall meet the requirements of the procedure documents;
b) Post-heating temperature is generally 200°C~350°C; holding time, in relation
to post-heating temperature and weld metal thickness, is generally not less than
30min;
c) Post-heating shall be carried out immediately after welding and post-heating
may be omitted if heat treatment is carried out immediately after welding.
4.6.6 Appearance inspection on welded joints of pressure parts
Welded joints of pressure parts (including those between pressure parts and main
loaded non-pressure parts) shall be subjected to appearance inspection according to
the following requirements:
a) Overall dimension of the weld shall meet the requirements of design drawing
and procedure document;
b) Weld height of butt joint shall not be less than that of the base material surface;
the weld and the base materials shall have smooth transition; the weld and the
heat-affected zone surface is free from crack, incomplete fusion, slag inclusion,
crater and gas cavity;
c) Longitudinal and circumferential welds of the shell, boiler furnace, header or
tubing and butt welds of the head, tube plate and foot ring shall be free from
undercut and undercut depth of other welds shall not exceed 0.5mm. Total
undercut length on both sides of the tube weld shall not exceed 20% the
perimeter of the tube or 40mm;
d) Connecting weld and base material between pressure parts and loaded non-
pressure parts shall have smooth transition and continuous weld; weld and
heat-affected zone surface shall be free from crack, incomplete fusion, slag
inclusion, crater and gas cavity etc. and the undercut depth is not greater than
0.5mm.
4.6.7 Repair welding
4.6.7.1 Where the weld requires repair, causes of defects shall be found out and
repair procedure shall be established according to the requirements of 4.6.1.
4.6.7.2 Before repair welding, the defect shall be thoroughly eliminated and repair
shall not be carried out in exposure to water.
4.6.7.3 After repair welding, the repair welding area shall be subjected to appearance
and non-destructive testing inspection. The parts requiring post-weld heat treatment
shall be subjected to post-weld heat treatment after repair welding.
4.6.7.4 The same position should not be repaired over 2 times; if over 2 times, it shall
be approved by the technical director of the organization and the repair positions, times
and conditions shall be kept in the technical files of the boiler product.
4.7 Heat treatment
4.7.1 Basic requirements
4.7.1.1 The fabrication organization shall prepare heat treatment procedure prior to
heat treatment according to corresponding standard and drawing requirements and
shall put forward procedure requirements for specific on-site heat treatment for
conditions requiring on-site heat treatment.
4.7.1.2 Coal-fired furnace shall not be used for post-weld heat treatment.
4.7.1.3 Heat treatment equipment shall be equipped with such device that
automatically records heat treatment time and temperature curve. The temperature
measuring device shall be able to reflect the actual temperature of the workpiece
accurately.
4.7.1.4 In the process of post-weld heat treatment, various parameters of heat
treatment specification shall be recorded in detail. After heat treatment, relevant
responsible personnel shall check, in detail, whether each record index is in
accordance with the procedure requirements.
4.7.2 Heat treatment for restorability of formed pressure parts
4.7.2.1 Where cold forming is adopted for the carbon steel and low-alloy steel plate,
their deformation rate shall not be greater than 5%. The deformation rate is calculated
according to Formulas (1) and (2) (see Figure 9):
shall be carried out for the carbon steel and alloy steel; solution treatment shall be
carried out for the austenitic stainless steel.
4.7.2.3 During step-by-step cold forming, if intermediate heat treatment is not carried
out, the deformation rate of the formed parts is the sum of the forming deformation
rates in each step; if intermediate heat treatment is carried out, sum of deformation
rates of the formed parts before and after the intermediate heat treatment shall be
calculated respectively.
4.7.2.4 Elimination of deformation and residual stress of warm forming workpieces,
if required, shall refer to cold forming conditions and requirements stated in 4.7.2.1 and
4.7.2.2.
4.7.2.5 If hot forming or warm forming destroys the material supply heat treatment
state, heat treatment shall be carried out again to restore the material supply heat
treatment state.
4.7.2.6 Any special requirements for heat treatment of forming temperature and
restoring the material supply heat treatment state, if any, shall comply with relevant
standards, specifications or design documents.
4.7.3 Post-weld heat treatment
4.7.3.1 It is determined whether the pressure parts is subjected to post-weld heat
treatment according to the material, post-weld heat treatment thickness δPWHT and
design requirements.
4.7.3.2 The pressure parts may be subjected to post-weld heat treatment only after
all the welding (including welding of non-pressure parts and their connection) work is
finished and passes the inspection.
4.7.3.3 Post-weld heat treatment shall be carried out before pressure test.
4.7.3.4 Post-weld heat treatment thickness δPWHT shall be determined according to
the following requirements:
a) Base material thickness for full penetration butt joints with uniform thickness;
b) Weld thickness for the butt weld and the fillet weld; larger thickness of the butt
weld and fillet weld for the composite weld;
c) During welding of parts in different thickness:
-- Base material thickness of thinner part for two adjacent butt pressure parts;
4.7.3.7 Post-weld heat treatment method shall be in accordance with the following
requirements:
a) Overall heating in the furnace shall be preferentially adopted for the post-weld
heat treatment;
b) In case of any failure in overall heat treatment, segmented heat treatment is
allowed to be adopted. If the segmented heat treatment is adopted, then each
heating segment at least shall have 1500mm overlap section. The external
furnace part shall be provided with insulation measures to avoid harmful
temperature gradients;
c) During repair welding and local heat treatment of circumferential weld, the weld
and the heating width on both sides of the weld shall not be less than 3 times
the steel plate thicknesses on both sides of the welded joints respectively
(whichever is larger) or 200mm. The width of the heater bank subjected to local
heat treatment shall guarantee that the temperature specification of the uniform
temperature zone within the coverage meets the requirements and the
insulation zone shall guarantee heat energy efficiency and avoid harmful
temperature gradients;
e) Where components are subjected to heat treatment by internal heating, they
shall be completely cladded in the insulation material.
4.7.3.8 If required, product welding specimen shall be subjected to the heat treatment
together with the representative products in the same furnace.
4.7.3.9 Parts shall avoid being directly welded on the boiler pressure parts after heat
treatment. In case of any failure, heat treatment may be omitted after welding where
the following conditions are met simultaneously, otherwise post-weld heat treatment
shall be carried out:
a) The pressure parts are of carbon steel or carbon manganese steel;
b) The calculated thickness of the fillet weld is not greater than 10mm;
c) Welding shall be in accordance with the welding procedure as deemed as
acceptable in qualification;
d) Non-destructive inspection shall be carried out for 100% surface of the fillet
weld.
4.8 Painting and packaging
4.8.3.5 Painting or anti-rust construction shall be avoided in the hot sun, rain and
snow or dense fog.
4.8.3.6 The painted part surface shall be uniform in the film and be free from such
defects as bubble, inclusion, cracking, peeling, base exposure, serious wrinkling or
stain etc. Otherwise, it shall be repaired until it is deemed as acceptable.
4.8.3.7 Where two or more than two layers of paint are coated, the next layer may
be painted after the previous layer gets dry and the previous layer of the film shall be
properly cleaned and be free from exposed undercoat.
4.8.4 Packaging
4.8.4.1 Product packaging shall meet the requirements of packaging design and
process document.
4.8.4.2 During delivery, the product shall be accompanied with shipping schedule (or
shipping list, packing list, the same below).
4.8.4.3 The product shall be bundled or packed according to the shipping schedule
after the paint gets dry and it passes the inspection. For cased parts, corresponding
packing list shall be prepared separately box by box; during packing, it shall be re-
checked in accordance with the packing list and its packing quality is inspected. After
it passes the inspection, it can be subjected to case sealing only after the packing list
is placed in box. The fabrication organization shall timely send out the shipping
schedule, so that users may check it and conduct acceptance thereby.
4.8.4.4 Wrapped or cased parts shall be accompanied with marks or labels, which
shall indicate production No. (or job number, delivery number, the same below), part
No. (or drawing No., the same below), name and quantity etc. For cased parts and
large-sized part or unpackaged parts for separate delivery, the above items may be
indicated at apparent positions by painting or other firm methods without additional
mark or label.
4.8.4.5 Parts which tend to be damaged or lost shall be packed and such parts that
are not easily damaged may be bundled or clamped firmly and reliably to avoid
looseness during loading/unloading, transportation and storage.
4.8.4.6 During packing, the parts shall be arranged closely, steadily and firmly to
avoid sliding or impact in box during the transportation and loading/unloading.
Fasteners for installation shall be bundled together or separately wrapped and
indicated with drawing No. and quality of their parts.
4.8.4.7 Precision or fragile parts shall be packed and filled with soft objects to avoid
vibration or impact. Parts that should not get moistened shall be packed with Kraft
paper or placed in the packaging box whose wall is padded with felt paper after the
adoption of damp-proof measures.
4.8.4.8 Moisture, dirt and foreign matters inside the shell, header and desuperheater
shall be cleaned up prior to packaging.
4.8.4.9 Tube orifices in expansion connection at the shell shall be coated with anti-
rust oil and covered with felt paper and wooden batten; tube joint, welded tube orifice
and uncased tube at the shell, header or desuperheater shall be closed. Besides anti-
rust oil, the flange sealing surface on the shell or header shall also be wrapped with
moisture-proof materials (such as Kraft paper, plastic paper or felt paper etc.) and
sealed well with a cover.
4.8.4.10 All the movable parts of the wrapping or packing parts shall be set to the
minimum overall dimension and be fixed.
4.8.4.11 Positions of the parts that they are placed in box shall be symmetrical as
much as possible and the gravity center should not exceed 1/2 height of the box.
4.8.4.12 Maximum dimension of cross section after packaging shall meet GB 146.1.
4.8.4.13 The product shall be convenient for lifting in either packing or bundling;
important parts shall be provided with lifting instructions and parts with relatively large
weight shall be specially designed with lifting structure.
4.8.4.14 Each packaging box shall be accompanied with transportation operation
mark and shipping mark; the former is in accordance with the requirements of GB 191,
while the latter is in accordance with the requirements of technical documents.
5 Inspection and Test
5.1 Appearance inspection
Material cutting, cold/hot forming and assembling of parts, expansion connection,
welding appearance inspection and dimension deviation shall meet the requirements
of Chapter 4.
5.2 Through ball test
5.2.1 Butt joint or bent tubes with the outside diameter of not greater than 60mm shall
be subjected to through ball test, pressure of the compressed air for test is about
0.6MPa. Steel ball shall be adopted as through ball. Through ball diameter db of the
5.4.2 Fabrication of product welding specimen
5.4.2.1 A piece of welding specimen shall be fabricated for the longitudinal joint of
each shell and header components. Longitudinal joint welding specimen shall be
welded as the extension of the longitudinal joint of the product.
5.4.2.2 Product welding specimen shall be welded by the welder for welding this
product, specimen material, welding material and process conditions etc. shall be the
same as those of their representative products; after welding, the specimen shall be
printed with the welder and the inspector.
5.4.2.3 If required, the specimen shall be subjected to heat treatment together with
the representative products in the same furnace.
5.4.2.4 Quantity and dimension of the product welding specimen shall be prepared
in accordance with specimen required for inspection and re-inspection.
5.4.3 Specimen preparation and performance inspection
5.4.3.1 The specimens are prepared at the acceptable parts, after being subjected
to appearance and non-destructive testing inspection.
5.4.3.2 As for the samples prepared on the specimen, their mechanical property
inspection category, specimen quantity, sampling and processing requirements, test
methods, acceptable indexes and re-inspection shall meet the requirements of NB/T
47016 (JB/T 4744). Meanwhile, longitudinal weld at the shell and header components
shall also be subjected to full-weld tensile inspection according to the relevant
requirements of 4.6.3.
5.5 Non-destructive testing
5.5.1 General requirements
The fabrication organization shall prepare non-destructive testing technology
according to the requirements of the design, technology and relevant technical
documents and it may be applied for non-destructive testing of corresponding product
after passing the test verification and evaluation.
5.5.2 Non-destructive testing method
5.5.2.1 Radiographic testing method shall be adopted for the butt joint with a
thickness of less than 2mm.
5.5.2.2 Ultrasonic testing method may be adopted for the butt joint with the thickness
of greater than or equal to 20mm; digital recording instrument should be adopted as
the ultrasonic testing instrument. If analog ultrasonic testing instrument is adopted,
additional 20% local radiographic testing shall be carried out. Where ultrasonic time of
flight diffraction (TOFD) technique is selected, it shall be combined with pulse echo
method (PE) for inspection.
5.5.2.3 Butt joint of the tube may be subjected to the radiographic testing by real-time
radiography imaging testing method.
5.5.2.4 Magnetic particle testing shall be preferentially adopted for the welding joint
surface of ferromagnetic material.
5.5.3 Non-destructive testing time
5.5.3.1 The nondestructive testing can be conducted for welded joints of the pressure
parts after passing shape and appearance quality inspection.
5.5.3.2 Materials with the delayed crack tendency shall be subjected to non-
destructive testing within 24h from the completion of welding.
5.5.3.3 Welded joints with the reheating crack tendency shall be subjected to non-
destructive testing on surface after the final heat treatment .
5.5.3.4 Non-destructive testing for splice joi...
......
 
(Above excerpt was released on 2019-08-17, modified on 2021-06-07, translated/reviewed by: Wayne Zheng et al.)
Source: https://www.chinesestandard.net/PDF.aspx/GBT16508.4-2013