Cast iron, copper and stainless steel valves with screwed connections
1 Scope
This document specifies the structural types, materials, technical requirements, test methods, inspection rules, as well as marking, packaging, transportation and storage of gate valve, globe valve, ball valve and check valve for cast iron, copper and stainless steel valves with screwed connections.
It is applicable to:
flake graphite iron cast valve with nominal pressure not greater than PN16 and nominal diameter not greater than DN100;
malleable iron cast valve and spheroidal graphite iron cast valve with nominal pressure not greater than PN25 and nominal diameter not greater than DN100;
copper alloy valve and stainless steel valve with nominal pressure not greater than PN40 and nominal diameter not greater than DN100.
The working temperature is not higher than 180℃, and the working medium is water, non-corrosive liquid, air, saturated vapor, etc.
Note 1: The valves in this document refer to gate valve, globe valve, ball valve or check valve with screwed connections.
Note 2: The working mediums for valves with nominal diameter greater than or equal to DN50 do not include air and saturated vapor.
2 Normative references
The following documents contain provisions 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 (including any amendments) applies.
GB/T 700 Carbon structural steels
GB/T 1176 Casting copper and copper alloys
GB/T 1184-1996 Geometrical tolerancing - Geometrical tolerance for features without individual tolerance indications
GB/T 1220 Stainless steel bars
GB/T 2828.1-2012 Sampling procedures for inspection by attributes - Part 1: Sampling schemes indexed by acceptance quality limit (AQL) for lot-by-lot inspection
GB/T 4380 Assessment of departure from roundness - Two-and three-point methods
GB/T 5750.6 Standard examination methods for drinking water - Metal parameters
GB/T 6461-2002 Methods for corrosion testing of metallic and other inorganic coatings on metallic substrates - Rating of test specimens and manufactured articles subjected to corrosion tests
GB/T 7306 (All parts) Pipe threads with 55 degree thread angle where pressure-tight joints are made on the threads
GB/T 7307 Pipe threads with 55 degree thread angle where pressure-tight joints are not made on the threads
GB/T 9440 Malleable iron castings
GB/T 10125-2021 Corrosion tests in artificial atmospheres - Salt spray tests
GB/T 12221 Metal valves - Face to face, end to end, center to face and center to end dimensions
GB/T 12224 General requirements for industrial steel valves
GB/T 12225 General purpose industrial valves - Specification of copper alloy castings
GB/T 12226 General purpose industrial valves - Specification of flake graphite iron castings
GB/T 12227 General purpose industrial valves - Specification of spheroidal graphite iron castings
GB/T 12230 General purpose industrial valves - Specification of stainless steel castings
GB/T 12716 Pipe threads with the thread angle of 60 degrees where pressure-tight joints are made on threads
GB/T 13927-2022 Industrial valves - Pressure testing
GB/T 15530.8 Specifications for copper alloy and composite flanges
GB/T 17241.7 Specifications for cast iron pipe flanges
GB/T 29528 Specification of copper alloy forgings for valves
GB/T 35741 Specification of stainless steel forgings for industrial valves
QB/T 5257 Polytetrafluoroethyieue (PTFE) sheet
3 Terms and definitions
For the purposes of this document, the following term and definition apply.
3.1 wrench
position where the mounting tool comes into contact with the head of the valve pipe threads when the valve is mounted and clamped to the pipe
4 Structural type
4.1 The typical structure of the gate valve with screwed connections is shown in Figure 1.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Structural type
5 Materials
6 Technical requirements
6.1 Pressure-temperature rating
6.2 Face to face, end to end, center to face and center to end dimensions
6.3 Connecting end
6.4 Minimum flow diameter
6.5 Body minimum wall thickness
6.6 Bonnet
6.7 Wrench
6.8 Wedge
6.9 Seat
6.10 Disc
6.11 Stem
6.12 Ball
6.13 Assembly
6.14 Operation
6.15 Appearance
6.16 Shell strength
6.17 Sealing performance
6.18 Precipitation of metal pollutants
6.19 Torsion resistance
6.20 Bending resistance
7 Test methods
7.1 Face to face, end to end, center to face and center to end dimensions
7.2 Connecting end
7.3 Minimum flow diameter
7.4 Minimum wall thicknesses of body and bonnet
7.5 Wrench
7.6 Wedge
7.7 Seat
7.8 Disc
7.9 Stem
7.10 Ball
7.11 Assembly
7.12 Operation
7.13 Appearance
7.14 Shell strength test
7.15 Sealing performance test
7.16 Precipitation of metal pollutants
7.17 Torsion resistance test
7.18 Bending resistance test
8 Inspection rules
8.1 Inspection classification
8.2 End-of-manufacturing inspection
8.3 Type test
9 Marking, packaging, transportation and storage
9.1 Marking
9.2 Packaging
9.3 Transportation
9.4 Storage
Annex A (Normative) Testing method for precipitation of metal pollutants
Figure 1 Typical structure of gate valve with screwed connections
Figure 2 Typical structure of globe valve with screwed connections
Figure 3 Typical structure of ball valve with screwed connections
Figure 4 Typical structure of check valve with screwed connections
Figure 5 Special devices for torsion resistance test
Figure 6 Special devices for bending resistance test
Figure A.1 Sample immersion procedure
Table 1 Materials for main parts of cast iron valves
Table 2 Materials for main parts of cast copper valves
Table 3 Materials for main parts of stainless steel valves
Table 4 Minimum flow diameter
Table 5 Minimum wall thickness of cast iron valve body
Table 6 Minimum wall thickness of cast copper valve body
Table 7 Minimum wall thickness of cast stainless steel valve body
Table 8 Minimum size of opposite sides of wrench
Table 9 Minimum stem diameter
Table 10 Precipitation limits of metal pollutants
Table 11 Torque
Table 12 Bending force
Table 13 End-of-manufacturing inspection items and acceptance quality limit (AQL)
Table 14 Type test items
Table 15 Sampling number
Table A.1 Expression of concentrations of metal pollutants
Table A.2 Expression of standardized concentrations
