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This standard is drafted in accordance with the rules given in GB/T 1.1-2009.
This standard replaces GB/T 22652-2008 Overlaying-welding procedure qualification for valves sealing face. The following main changes have been made with respect to GB/T 22652-2008:
——The terms "weld metal overlaying procedure specification" and "preliminary weld metal overlaying procedure specification", "procedure qualification record", “weld metal overlaying working instruction”, "lower transformation temperature” and “post weld heat treatment” are added (see 3.1);
——The commonly-used abbreviations for procedure qualification are added (see 3.2);
——The commonly-used parent metals for valve overlaying-welding and their classes and groups (see 5.2);
——The elements of procedure qualification are modified (see 5.5; 5.1 in Edition 2008);
——The classification of filler metals (electrode, welding wire and welding powder) and the rules for procedure qualification are added (see 5.3 and 6.3);
——The tubular overlaying-welding test pieces are added and their sampling positions are specified (see 7.1);
——Three annexes are added, namely, “Flow chart for weld metal overlaying procedure specification”, “Supplementary provisions on parent metals, filler metals and overlaying-welding methods”, and “Recommended formats for procedure qualification forms” (see Annexes A, B and C).
This standard was proposed by China Machinery Industry Federation.
This standard is under the jurisdiction of National Technical Committee on Valve of Standardization Administration of China (SAC/TC 188).
The previous edition of this standard is as follows:
——GB/T 22652-2008.
Overlaying-welding procedure qualification for valves sealing face
1 Scope
This standard specifies the general requirements for overlaying-welding on valves sealing face, corresponding procedure qualification factors, classification and rules, test requirements and test piece inspection, supplementary provisions on overlaying-welding qualification, and recommended formats for preliminary weld metal overlaying procedure specification and for procedure qualification record.
This standard is applicable to the procedure qualification of plasma arc overlaying-welding, oxygen fuel gas overlaying-welding, shielded metal arc overlaying-welding, submerged overlaying-welding, gas metal arc overlaying-welding, gas tungsten arc overlaying-welding and other overlaying-welding methods for hardfacing on the valves sealing face.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendments) applies.
GB/T 699 Quality carbon structure steels
GB/T 700 Carbon structural steels
GB/T 713 Steel plates for boilers and pressure vessels
GB/T 984 Hardfacing electrodes for shielded metal arc welding
GB/T 1220 Stainless steel bars
GB/T 2054 Nickel and nickel alloy plate and sheet
GB/T 3077 Alloy structure steels
GB/T 3274 Hot-rolled plates, sheets and strips of carbon structural steels and high strength low alloy structural steels
GB/T 3280 Cold rolled stainless steel plate, sheet and strip
GB/T 4237 Hot rolled stainless steel plate, sheet and strip
GB/T 4435 Nickel and nickel alloys bars
GB/T 11352 Carbon steel castings for general engineering purpose
GB/T 12228 General purpose industrial valves - Specification of carbon steel forgings
GB/T 12229 General purpose industrial valves - Specification of carbon steel castings
GB/T 12230 General purpose industrial valves - Specification of stainless steel castings
GB/T 13296 Seamless stainless steel tubes for boiler and heat exchanger
GB/T 15008 Corrosion-resistant alloy bars
GB/T 16253 Steel castings for pressure purposes
GB/T 21832 (All parts) Austenitic - Ferritic (duplex) grade stainless steel welded tubes and pipes
GB/T 21833 Austenitic-Ferritic (Duplex) Grade Stainless Steel Seamless Tubes and Pipes
GB/T 24511 Stainless steel and heat resisting steel plates, sheets and strips for pressure equipment
JB/T 4743 Nickel - copper alloy forgings for pressure vessels
JB/T 5263 Specification for steel casting for power station valves
JB/T 6438 Technical requirements for plasma arc overlaying welding for valve sealing surface
JB/T 7248 Technical specification for low temperature service steel casting for valves
JB/T 7744 Alloy powder used for plasma arc overlaying welding for valve sealing surface
JB/T 9625 Specification for pressure retaining casting of boiler pipe fittings
JB/T 10087 Specifications for steel casting of steam turbines for pressure purposes
JB/T 12000 Specification of the forged steel parts for the pressure valves in supercritical and ultra-supercritical steam power plants
NB/T 47008 Carbon and alloy steel forgings for pressure equipment
NB/T 47009 Alloy steel forgings for low temperature pressure equipment
NB/T 47010 Stainless and heat-resisting steel forgings for pressure equipment
NB/T 47013.5 Nondestructive testing of pressure equipment - Part 5: Penetrant testing
NB/T 47044 Power station valves
NB/T 47046 Nickel-nickel alloy plate for pressure equipments
YB/T 5264 Corrosion-resisting alloy forging
YB/T 5353 Hot-rolled plates of corrosion-resisting alloys
YB/T 5354 Cold-rolled plates of corrosion-resisting alloys
3 Terms, definitions and abbreviations
3.1 Terms and Definitions
For the purpose of this document, the following terms and definitions apply.
3.1.1
sealing face
contact face formed when the disc is closely attached to the seat, playing a sealing role
3.1.2
overlaying-welding
process of forming a metal cladding layer by welding
Note: overlaying-welded valves sealing face is able to prevent and reduce the wear, corrosion and/or erosion of the sealing face.
3.1.3
weld metal overlaying procedure specification
overlaying-welding procedure document that is prepared according to the qualified procedure qualification record and used for implementation of overlaying-welding on products
3.1.4
preliminary weld metal overlaying procedure specification
overlaying-welding procedure documents drafted for procedure qualification
3.1.5
procedure qualification record
record describing the verification test and inspection results, for evaluating the drafted preliminary weld metal overlaying procedure specification
3.1.6
buttering
cladding layer manufactured using various overlaying-welding methods in order to ensure the quality of cladding layer between overlaying-welding layers, improve the welding performance of joints and prevent defects such as cracks and pores in subsequent overlaying-welding
3.1.7
weld metal overlaying working instruction
detailed working documents of processing and operation related to manufacturing weldments
Note: the working instruction is used by welders while conducting welding, able to ensure the reproducibility of quality during construction
3.1.8
lower transformation temperature
phase-transition temperature at which austenite begins to form during heating
3.1.9
post weld heat treatment
thermal process that can change the structure and performance of overlaying-welding layers or overlaying-welding residual stress
3.2 Abbreviations
For the purposes of this document, the following abbreviations apply.
pWPS: preliminary weld metal overlaying procedure specification
PQR: procedure qualification record
WPS: weld metal overlaying procedure specification
WWI: weld metal overlaying working instruction
4 General requirements
4.1 General
4.1.1 Procedure qualification shall be based on welding performance of the parent metal for valves sealing face and shall be completed before overlaying-welding of valve products.
4.1.2 The general process of procedure qualification is as follows: draw up pWPS based on the welding performance of parent metal and according to the design documents and manufacturing procedure, weld test pieces and prepare specimens and inspect test pieces and specimens to determine whether the overlaying-welding layers meet the specified requirements and formulate PQR to evaluate pWPS, and finally formulate WPS or WWI used for production implementation.
4.1.3 The procedure qualification shall be carried out in manufacturing unit. The equipment and instruments used in procedure qualification shall be in normal working state, the parent metal and overlaying-welding materials shall conform to the corresponding standards, and the overlaying-welding test pieces shall be completed by the welders with skilled operation skills of the manufacturing unit using the equipment of the same unit.
4.1.4 The chemical composition, hardness of overlaying-welding layer and particle size of overlaying-welding electrode (hereinafter referred to as electrode), overlaying-welding alloy powder (hereinafter referred to as alloy powder) and overlaying-welding wire (hereinafter referred to as welding wire) shall conform to GB/T 984, JB/T 7744 and NB/T 47044.
Foreword II
1 Scope
2 Normative references
3 Terms, definitions and abbreviations
3.1 Terms and Definitions
3.2 Abbreviations
4 General requirements
4.1 General
4.2 Weld metal overlaying procedure specification
5 Procedure qualification factors and their classification
5.1 Classification of overlaying-welding methods
5.2 Classification of parent metal
5.3 Filler metals and their classification
5.4 Post weld heat treatment methods and their classification
5.5 Procedure qualification factors and their classification
6 Rules for procedure qualification
6.1 Rules for qualification of overlaying-welding methods
6.2 Rules for qualification of parent metals
6.3 Rules for qualification of filler metals
6.4 Rules for qualification of post weld heat treatment
6.5 Rules for qualification of overlaying-welding buttering
6.6 Rules for qualification of the thickness of parent metal of test piece and that of parent metal of weldment
7 Test requirements and test piece inspection
7.1 Preparation of test pieces
7.2 Test piece inspection
8 Supplementary provisions on overlaying-welding qualification
9 Recommended formats for pWPS and PQR
Annex A (Informative) Flow chart for weld metal overlaying procedure specification
Annex B (Informative) Supplementary provisions on parent metals, filler metals and overlaying-welding methods
Annex C (Informative) Recommended formats for procedure qualification forms
