GB/T 12229-2025 General purpose Industrial valves - Technical specification for carbon steel castings 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 12229-2025
Replaces GB/T 12229-2005
General purpose Industrial valves - Technical specification for carbon steel castings
通用阀门 素钢铸件技术规范
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 Casting Process and Evaluation
4.2 Chemical Composition
4.3 Mechanical Properties
4.4 Heat Treatment
4.5 Dimensions and Weight
4.6 Appearance
4.7 Shell Test
4.8 Welding Repair
5 Test Methods
5.1 Chemical Analysis
5.2 Mechanical Property Testing
5.3 Dimensional Inspection
5.4 Visual Inspection
5.5 Shell Test
6 Marking and Quality Certificate
6.1 Marking
6.2 Quality Certificate
7 Additional Requirements
Appendix A (Informative) Additional Requirements
References
Table 1 Chemical Composition (Mass Fraction)
Table 2 Room Temperature Tensile Test Results
Table A.1 Average Impact Absorption Energy Values
Table A.2 High Temperature Tensile Test
Table A.3 Acceptable Grades for Porosity, Sand Inclusions, Slag Inclusions, Shrinkage Cavities, and Shrinkage Porosity Defects
1 Scope
This document specifies the technical requirements, test methods, marking, quality certificates, and additional requirements for carbon steel castings used in general valves.
This document applies to the design, production, and inspection of pressure-bearing carbon steel castings for general valves. Non-pressure-bearing carbon steel castings may refer to this document for use.
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 Technical Requirements
4.1 Casting Process and Evaluation
4.1.1 Casting Process
The casting process shall be evaluated as qualified before being used for batch production of castings.
4.1.2 Casting Process Evaluation
4.1.2.1 The casting process evaluation shall be conducted under the following circumstances:
a) First production of molds;
b) Major changes in the casting process design, such as modifications to the gating and riser system;
c) Changes in production conditions, such as alterations in site, melting equipment, or major raw materials and auxiliary materials;
d) Discovery of casting defects related to the process design during batch production.
4.1.2.2 The casting process evaluation report shall include at least the following contents:
a) Casting process design documents;
b) Heat treatment records or reports;
c) Chemical composition and mechanical property test reports;
d) Visual inspection reports;
e) Dimensional inspection reports;
f) Magnetic particle inspection reports;
g) Radiographic inspection reports.
4.2 Chemical Composition
The chemical composition of castings shall comply with Table 1.
4.3.2 The allowable deviation for finished product analysis shall comply with GB/T 222.
4.4 Heat Treatment
4.4.1 Heat treatment of castings shall be performed in accordance with written procedures.
4.4.2 Heat treatment shall be carried out by normalizing, normalizing followed by tempering, or quenching followed by tempering. The holding temperature for normalizing or quenching shall be 900°C to 980°C, and the holding temperature for tempering shall be 600°C to 720°C.
4.4.3 The effective heating zone of heat treatment furnaces shall be measured in accordance with GB/T 9452—2023. The temperature uniformity and instrument accuracy of furnaces used for normalizing or quenching shall meet the requirements of Class V equipment, while those used for tempering shall meet the requirements of Class III equipment.
4.4.4 The holding time for normalizing or quenching heat treatment shall be calculated based on the maximum pressure-bearing wall thickness of the castings in the furnace. If the maximum pressure-bearing wall thickness is ≤25 mm, the holding time shall be ≥1 hour. For every 25 mm increase in thickness, the holding time shall increase by 1 hour. The tempering holding time shall be no less than the normalizing or quenching holding time.
4.5 Dimensions and Weight
The dimensions and deviations of castings shall comply with the requirements of the drawings provided by the purchaser. If the drawing does not specify dimensional deviation requirements, the dimensional tolerances, geometric tolerances, and machining allowances for castings shall comply with GB/T 6414. The weight tolerance of castings shall comply with GB/T 11351.
4.6 Appearance
4.6.1 Before delivery, castings shall undergo surface treatment, and their appearance quality shall comply with the requirements of JB/T 7927. Surface roughness shall meet the requirements of the purchaser's drawings.
4.6.2 Castings shall not be sealed against leakage by hammering, plugging, or impregnation.
4.6.3 Core supports shall not be used for castings. If core supports cannot be avoided, they shall be completely removable during machining and shall not cause material changes or cracks in the castings.
4.7 Shell Test
The shell test may be conducted by either the supplier or the purchaser. The acceptance criteria shall be determined by the purchaser, and the supplier shall be responsible for the quality of the castings.
4.8 Welding Repair
4.8.1 Welding repair of castings shall be performed in accordance with qualified welding procedures, and the welding procedure qualification shall comply with GB/T 40800.
4.8.2 Welders performing welding repairs on castings shall hold relevant qualification certificates issued after passing examinations in accordance with GB/T 15169.
4.8.3 The welding repair area and its heat-affected zone shall be inspected after repair, and the acceptance criteria shall not be lower than those for the castings.
4.8.4 The following welding repairs are considered major welding repairs:
