GB/T 12227-2025 General purpose industrial valves - Technical specification for ductile 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 12227-2025
Replaces GB/T 12227-2005
General purpose industrial valves - Technical specification for ductile iron castings
通用阀门 球墨铸铁件技术规范
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 Metallographic examination
4.8 Surface quality
4.9 Casting defects and repair
4.10 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 Metallographic examination
5.8 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 properties of spheroidal graphite cast iron samples
Table 2 Minimum impact energy absorption of V-notched samples machined from spheroidal graphite cast iron samples
Table 3 Inspection items
Table 4 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 ferritic topearlitic spheroidal graphite cast iron components of general-purpose valves.
This document applies to the design, production, and inspection of ferritic topearlitic spheroidal graphite cast iron (hereinafter referred to as "spheroidal graphite 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 229 - Metallic materials - Charpy pendulum impact test method
GB/T 1348 - Spheroidal graphite castings
GB/T 5611 - Casting terminology
GB/T 6414 - Castings - Dimensional tolerances, geometric tolerances and machining allowances
GB/T 9441 - Ferritic topearlitic spheroidal graphite cast iron - Microstructure inspection
GB/T 9441-2021 - Ferritic topearlitic spheroidal graphite cast iron - Microstructure inspection
GB/T 11351 - Castings - Weight tolerances
GB/T 12220 - Industrial valves - Marking
GB/T 13927 - Industrial valves - Pressure testing
3 Terms and definitions
The terms and definitions defined in GB/T 5611 and the following apply to this document.
3.1
Ferritic topearlitic spheroidal graphite cast iron - A spheroidal graphite cast iron containing ferrite, pearlite, or a mixture of ferrite and pearlite as the matrix.
3.2
Side-by-side cast sample - A sample cast using the same pouring system as the casting and poured alongside the casting.
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 the castings shall be determined by the supplier. 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 properties of the spheroidal graphite cast iron samples shall comply with the provisions of Table 1.
4.5.2 The minimum impact energy absorption of the spheroidal graphite cast iron samples shall comply with the provisions of Table 2.
Table 1 Tensile properties of spheroidal graphite cast iron samples
Table 2 Minimum impact energy absorption of spheroidal graphite cast iron samples
4.6 Pressure test
The pressure test of pressure-bearing castings shall comply with the provisions of GB/T 13927.
4.7 Microstructure inspection
4.7.1 The preparation of the samples shall comply with the provisions of GB/T 9441.
4.7.2 The spheroidal graphite cast iron components shall have a graphitization grade of no less than Grade 4 according to GB/T 9441-2021.
4.8 Surface quality
4.8.1 The casting surfaces shall be free from adhering sand, pouring gates, risers, fins, burrs, etc.
4.8.2 After cutting the castings using thermal processing methods, the material in the heat-affected zone shall be removed.
4.8.3 The surface roughness (Ra) of the castings shall not exceed 25 μm, or as required by the buyer's drawings or product standards.
4.8.4 The castings shall meet the buyer's anti-rust requirements upon delivery.
4.9 Casting defects and repair
4.9.1 Casting defects (such as cracks, blowholes, inclusions, shrinkage, cold shuts, etc.) that affect the service performance of the castings shall not exist.
4.9.2 Castings shall not be repaired by hammering, plugging, or impregnation to eliminate leakage defects.
4.9.3 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. If necessary, the requirements shall be specified in the contract.
4.10 Stress relief treatment
The supplier shall subject the castings to stress relief treatment.
5 Test methods
5.1 Geometric shape and dimensional tolerances
Measure using calipers and other measuring tools.
5.2 Machining allowances
Measure using calipers and other measuring tools.
