GB/T 12232-2025 General purpose industrial valves - Flanged iron gate valves English, Anglais, Englisch, Inglés, えいご
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ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 12232-2025
Replaces GB/T 12232-2005
General purpose industrial valves - Flanged iron gate valves
通用阀门 法兰连接铁制闸阀
Issue date: 2025-10-31 Implementation date: 2026-05-01
Issued by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
the Standardization Administration of the People's Republic of China
Contents
Foreword
1 Scope
2 Normative References
3 Terms and Definitions
4 Structural Types
5 Technical Requirements
5.1 Pressure-Temperature Rating
5.2 Shell Wall Thickness
5.3 Valve Body and Cover
5.4 Gate
5.5 Stem and Stem Nut
5.6 Packing and Packing Gasket
5.7 Gland
5.8 Bracket
5.9 Handwheel
5.10 Indicator
5.11 Valve Operation
5.12 Bypass and Drainage
5.13 Hook and Base
5.14 Shell and Seal Test
5.15 Sanitary Requirements
5.16 Materials
6 Test Methods
6.1 Shell Wall Thickness Measurement
6.2 Stem Diameter Measurement
6.3 Opening and Closing Operation Test
6.4 Pressure Test
6.5 Valve Body Material Mechanical Properties
6.6 Sanitation
7 Inspection Rules
7.1 Factory Inspection
7.2 Type Inspection
8 Marking
9 Supply Requirements
Figure 1 Typical Structure of Rising Stem Gate Valve
Figure 2 Typical Structure of Non-Rising Stem Gate Valve
1 Scope
This document specifies the structural types, technical requirements, test methods, inspection rules, marking, and supply requirements for flanged iron gate valves.
This document is applicable to the design, production, and inspection of flanged gray cast iron and ductile cast iron gate valves (hereinafter referred to as "gate valves") with nominal pressure PN2.5 to PN25 and nominal sizes DN50 to DN2000.
2 Normative References
The provisions of the following documents constitute essential clauses of this document through normative references in the text. For dated references, only the version published on the cited date applies. For undated references, the latest version (including all amendments) applies.
3 Terms and Definitions
This document does not require the definition of terms and definitions.
4 Structural Types
The typical structure of a rising stem gate valve is shown in Figure 1, and the typical structure of a non-rising stem gate valve is shown in Figure 2.
5 Technical Requirements
5.1 Pressure-Temperature Ratings of Gate Valves
The pressure-temperature ratings of gate valves shall comply with the provisions of GB/T 17241.1.
5.2 Shell Wall Thickness
5.2.1 The material grade of the gate valve body (valve body and bonnet) shall not be lower than gray cast iron material HT200 and ductile cast iron material QT450-10. The minimum wall thickness of the valve body shall comply with the provisions of Table 1.
5.2.2 For gate valves with a nominal size of DN250 or larger, reinforcing ribs or other measures may be considered to increase the stiffness of the shell and ensure that the valve does not undergo harmful deformation under pressure testing and operating conditions.
5.3 Valve Body and Bonnet
5.3.1 The flanges at the connection ends of the valve body shall be integrally cast with the valve body and shall comply with the provisions of GB/T 17241.1.
5.3.2 The structural length and dimensional tolerances of the valve body shall comply with the provisions of GB/T 12221.
5.3.3 The flow passage size of the valve body shall be consistent with the flange connection end size, and the seat bore shall be consistent with the flow passage size.
5.3.4 The connection between the valve body and the bonnet shall be of the flange type, and the flange sealing face may be of the flat face or raised face type.
5.3.5 The connection bolts and their number between the valve body and the bonnet shall ensure the strength and sealing requirements under conditions such as shell pressure testing, lifting, and use.
5.3.6 For gate valves with a nominal size of DN200 or larger, an exhaust vent hole may be provided at the upper part of the bonnet, which shall be sealed.
5.3.7 The valve body shall be provided with a guide rail that cooperates with the gate.
5.3.8 The sealing surface of the valve body may be surfaced with copper alloy, and the thickness of the surfaced layer after machining shall not be less than 2 mm; it may also be inlaid with a copper alloy ring, ensuring that it does not loosen or detach during use, and there shall be no leakage at the junction of the inlaid structure.
5.4 Gate
5.4.1 The gate shall have a guide groove that cooperates with the valve body to ensure that the gate moves along the valve body guide during opening and closing, and that the symmetrical centerline of the gate sealing surface is parallel to the stem axis at any position, minimizing wear on the sealing surfaces.
5.4.2 The sealing surface of the gate may be surfaced with copper alloy, and the thickness of the surfaced layer after machining shall not be less than 2 mm, or it may be inlaid with a copper alloy ring. The inlaid type shall not loosen or detach during use, and there shall be no leakage at the junction of the inlaid structure.
5.4.3 When the gate valve is fully open, the gate shall be higher than the inner diameter of the passage.
5.4.4 The sealing surface of the wedge gate shall have sufficient width to ensure complete contact with the seat after wear.
5.4.5 The two gates of a double gate shall be reliably connected to ensure that they do not detach.
5.5 Stem and Stem Nut
5.5.1 The connection between the stem and the gate and the stem nut shall ensure that the gate does not detach during the opening and closing operation of the gate valve.
5.5.2 The minimum diameter of the stem refers to the outer diameter of the stem in contact with the packing and shall comply with the provisions of Table 2.
Table 2 Minimum Stem Diameter
5.5.3 The basic dimensions and tolerances of the stem nut and stem thread shall comply with GB/T 5796 (all parts).
5.5.4 The engaged length between the stem and stem nut shall not be less than 1.4 times the stem diameter.
5.6 Packing and Packing Gasket
5.6.1 For stem sealing with packing, the packing cross-section before compression may be square, rectangular, or V-shaped. Formed packing shall be used, and open-end packing shall not be used. A metal packing gasket is recommended at the bottom of the packing box.
5.6.2 For stem sealing with O-rings, at least two O-rings shall be used, and external dust seals are recommended.
5.7 Gland
5.7.1 The gland shall be of solid or split type with holes, and the bolt holes shall not be of open type.
5.7.2 The gland connection may use T-bolts or union bolts.
