General purpose industrial valves - Specification of stainless steel castings
1 Scope
This document specifies the technical requirements, test methods, inspection rules, marking and quality certification as well as additional requirements of stainless steel castings for general purpose industrial valves.
This document is applicable to austenitic stainless steel castings for pressure purpose.
Austenitic stainless steel castings not for pressure purpose can be used for reference.
2 Normative references
The following documents contain requirements which, through reference in this text, constitute provisions of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 228.1 Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 5678 Sampling methods of spectrochemical analysis for cast alloys
GB/T 6414 Castings - Dimensional tolerances and geometrical tolerances and machining allowances
GB/T 9452 Testing method for working zone of heat treatment furnace
GB/T 11351 Mass tolerances for castings
GB/T 13927 Industrial valves - Pressure testing
GB/T 15056 Casting surface roughness - Appraising method
GB/T 15169 Qualification test of welders - Fusion welding for steels
GB/T 16253-2019 Steel castings for pressure purposes
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition
GB/T 26480 Valve inspection and testing
GB/T 32541-2016 Quality control system for heat treatment
JB/T 7927 Valve cast steel visual quality requirements
NB/T 47014 Welding procedure qualification for pressure equipment
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
casting for pressure purpose
casting in contact with the medium and bearing its pressure
Note: Such as valve bodies, valve covers and valve discs
3.2
heat number
identifier composed of alphanumericals or alphabets and numbers to identify the casting cast by molten steel of a specific furnace
3.3
test coupon
part cast by molten steel that is from the same furnace as the casting for processing specimens for tests on mechanical properties and others
3.4
specimen
part of test coupon to be used for tests on mechanical properties and others
3.5
solution heat treatment
heat treatment process which consists of heating the castings to a suitable temperature and holding them at that temperature long enough to allow surplus phase to fully dissolve, and then rapidly cooling to obtain supersaturated solid solution
3.6
stabilization heat treatment
heat treatment process for improving intergranular corrosion resistance of austenitic stainless steel containing titanium or niobium
4 Technical requirements
4.1 Smelting
The castings shall be smelted by electric furnaces or refining furnaces, such as argon oxygen decarburization (AOD) furnaces.
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Technical requirements
4.1 Smelting
4.2 Casting process and evaluation
4.3 Cutting of gate and casting head
4.4 Chemical composition of castings
4.5 Mechanical properties
4.6 Heat treatment
4.7 Dimension and mass
4.8 Appearance test
4.9 Housing test
4.10 Repair welding
5 Test methods and inspection rules
5.1 Chemical composition analysis
5.2 Mechanical property test
5.3 Dimensional inspection
5.4 Appearance test
5.5 Housing test
6 Marking and quality certificate
6.1 Marking
6.2 Quality certificate
7 Additional requirements
Annex A (Informative) Additional requirements
Bibliography
Table 1 Chemical composition
Table 2 Test on mechanical properties at ambient temperature
Table 3 Heat treatment mode, holding temperature and cooling method
Table A.1 Nonmetallic inclusion grade
Table A.2 Low temperature impact test temperature and average impact absorption energy
