GB/T 12226-2025 General purpose industrial valves - Technical specification for gray iron castings English, Anglais, Englisch, Inglés, えいご
This is a draft translation for reference among interesting stakeholders. The finalized translation (passing through draft translation, self-check, revision and verification) will be delivered upon being ordered.
ICS 13.220.10
CCS H 57
National Standard of the People's Republic of China
GB/T 12226-2025
Replaces GB/T 12226-2005
General purpose industrial valves - Technical specification for gray iron castings
通用阀门 灰铸铁件技术规范
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 Technical requirements
4.1 Geometric shape and dimensional tolerances
4.2 Machining allowances
4.3 Weight deviation
4.4 Chemical composition
4.5 Mechanical properties
4.6 Pressure test
4.7 Surface quality
4.8 Casting defects and repair
4.9 Stress relief treatment
5 Test methods
5.1 Geometric shape and dimensional tolerances
5.2 Machining allowances
5.3 Weight deviation
5.4 Chemical composition
5.5 Mechanical properties
5.6 Pressure test
5.7 Surface quality
6 Inspection rules
6.1 Inspection classification
6.2 Factory inspection
6.3 Type test
6.4 Batch, sampling methods and judgment rules
7 Marking, labeling and accompanying documents
7.1 Marking content
7.2 Label
7.3 Accompanying documents
8 Packaging, transportation and storage
8.1 Packaging
8.2 Transportation
8.3 Storage
Table 1 Tensile strength
Table 2 Inspection items
Table 3 Sampling quantity table
1 Scope
This document specifies the technical requirements, test methods, inspection rules, marking and labeling, accompanying documents, as well as packaging, transportation, and storage for gray cast iron components of general-purpose valves.
This document applies to the design, production, and inspection of gray cast iron components for general-purpose valves.
2 Normative references
The contents of the following documents, through normative references in this text, constitute indispensable clauses of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including all amendments) applies.
GB/T 191 - Pictorial markings for handling of goods
GB/T 228.1 - Metallic materials - Tensile testing - Part 1: Method of test at room temperature
GB/T 231.1 - Metallic materials - Brinell hardness test - Part 1: Test method
GB/T 6414 - Castings - Dimensional tolerances, geometric tolerances and machining allowances
GB/T 9439 - Gray cast iron castings
GB/T 11351 - Castings - Weight tolerances
GB/T 12220 - Industrial valves - Marking
GB/T 13927 - Industrial valves - Pressure testing
3 Terms and definitions
There are no terms and definitions that need to be defined in this document.
4 Technical requirements
4.1 Geometric shape and dimensional tolerances
The geometric shape and dimensions of the castings shall conform to the drawings. The dimensional tolerances of the castings shall comply with the provisions of GB/T 6414. Special requirements may also be implemented according to the buyer's drawings and technical requirements.
4.2 Machining allowances
Machining allowances shall be provided on the necessary parts of the castings in accordance with the provisions of GB/T 6414 or the requirements of the buyer's casting drawings and patterns.
4.3 Weight deviation
The weight deviation of the castings shall comply with the provisions of GB/T 11351.
4.4 Chemical composition
The chemical composition of gray cast iron castings shall be determined by the supplier. The chemical composition shall not be the basis for the acceptance of castings, but the selection of chemical composition shall meet the mechanical performance requirements of the castings. If the buyer has special requirements, the chemical composition shall be determined through negotiation between the supplier and the buyer.
4.5 Mechanical properties
4.5.1 The tensile strength of single-cast test bars, side-by-side test bars, or attached test blocks shall comply with the provisions of Table 1.
4.5.2 If the buyer requires hardness as the inspection criterion for the mechanical properties of the castings, it shall be specified in the contract.
Table 1 Tensile strength
4.6 Pressure testing
4.6.1 The pressure test results of pressure-bearing castings shall comply with the provisions of GB/T 13927.
4.6.2 The pressure test for pressure-bearing castings may be conducted either before delivery by the supplier or after machining by the buyer. However, the supplier shall be responsible for the quality of the pressure-tested castings.
4.7 Surface quality
4.7.1 The casting surfaces shall be free from adhering sand, pouring gates, risers, fins, burrs, etc.
4.7.2 The surface roughness (Ra) of the castings shall not exceed 25 μm, or as required by the buyer's drawings or product standards.
4.7.3 The castings shall meet the buyer's anti-rust requirements upon delivery.
4.8 Casting defects and repairs
4.8.1 Casting defects (such as cracks, blowholes, inclusions, shrinkage, cold shuts, etc.) that affect the service performance of the castings shall not exist.
4.8.2 Castings shall not be repaired by hammering, plugging, or impregnation to eliminate leakage defects.
4.8.3 The machined surfaces of castings shall not be welded or repaired. Casting defects that do not affect service performance may be repaired, and the technical requirements for repair shall be agreed upon between the supplier and the buyer.
4.9 Stress relief treatment
The supplier shall subject the castings to stress relief treatment.
5 Test methods
5.1 Geometric shape and dimensional tolerances
The geometric shape and dimensions of the castings shall be inspected in accordance with the drawings. The dimensional tolerances of the castings shall be inspected in accordance with the provisions of GB/T 6414. Special requirements may also be inspected in accordance with the buyer's drawings and technical requirements.
5.4 Chemical composition
5.4.1 When required by the purchaser, the castings shall be subjected to spectrographic analysis or chemical composition analysis.
5.4.2 Spectrographic analysis and chemical composition analysis shall be carried out in accordance with the provisions of GB/T 9439.
