GB/T 7659-2025 Steel castings for welding structures
1 Scope
This document specifies the grade, manufacturing, technical requirements, test methods, inspection rules as well as marking, packaging, transportation and storage of steel castings for welding structures.
This document is applicable to the manufacturing of steel castings for welding structures (hereinafter referred to as "castings").
2 Normative references
The following normative 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 of the referenced document (including any amendments) applies.
GB/T 222 Permissible tolerances for chemical composition of steel products
GB/T 223.5 Steel and iron - Determination of acid-soluble silicon and total silicon content - Reduced molybdosilicate spectrophotometric method
GB/T 223.11 Iron, steel and alloy - Determination of chromium content - Visual titration or potentiometric titration method
GB/T 223.13 Methods for chemical analysis of iron, steel and alloy - The ammonium ferrous sulfate titration method for the determination of vanadium content
GB/T 223.18 Methods for chemical analysis of iron, steel and alloy - The sodium thiosulfate separation iodimetric method for the determination of copper content
GB/T 223.23 Iron, steel and alloy - Determination of nickel content - The dimethylglyoxime spectrophotometric method
GB/T 223.26 Iron, steel and alloy - Determination of molybdenum content - The thiocyanate spectrophotometric method
GB/T 223.59 Iron, steel and alloy - Determination of phosphorus content - Bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method
GB/T 223.69 Iron, steel and alloy - Determination of carbon contents - Gas-volumetric method after combustion in the pipe furnace
GB/T 223.72 Iron, steel and alloy - Determination of sulfur content - Gravimetric method
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 4336 Carbon and low-alloy steel - Determination of multi-element contents - Spark discharge atomic emission spectrometric method (routine method)
GB/T 5611 Foundry terminology
GB/T 5613 Designation for cast steels
GB/T 5677 Castings - Radiographic testing
GB/T 6060.1 Surface roughness comparison specimen - Part 1: Casting surface
GB/T 6414 Castings - Dimensional tolerances and geometrical tolerances and machining allowances
GB/T 7233.1 Steel castings - Ultrasonic examination - Part 1: Steel castings for general purposes
GB/T 9443 Steel and iron castings - Liquid penetrant inspection
GB/T 9444 Steel and iron castings - Magnetic particle inspection
GB/T 11351 Mass tolerances for castings
GB/T 15056 Casting surface roughness - Appraising method
GB/T 15169 Qualification test of welders - Fusion welding for steels
GB/T 16923 Normalizing and annealing of steel parts
GB/T 16924 Quenching and tempering of steel parts
GB/T 20066 Steel and iron - Sampling and preparation of samples for the determination of chemical composition
GB/T 20125 Low-alloy steel - Determination of multi-element contents - Inductively coupled plasma atomic emission spectrometric method
GB/T 39428-2020 Steel castings by sand casting - Visual examination method of surface quality
GB/T 39638 X-ray digital radiographic testing for casting
GB/T 40800 Specification and qualification of welding procedures for production welding of steel castings
GB/T 40805 Steel castings - General technical delivery requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in GB/T 5611 apply.
4 Grade
The method for representing casting grades shall meet the requirements of GB/T 5613. According to the performance grade of materials, there are a total of five material grades: ZGH200-380, ZGH240-450, ZGH270-480, ZGH300-500 and ZGH340-550.
5 Manufacturing
5.1 Casting and heat treatment
5.1.1 Unless otherwise specified by the purchaser, the smelting process and casting process shall be determined by the supplier.
5.1.2 The chaplet and internal chill shall not be used without the written permission of the purchaser.
5.1.3 Unless otherwise specified, the castings shall be subjected to heat treatment, and the heat treatment process shall be determined by the supplier, and meet the requirements of GB/T 16923 and GB/T 16924.
5.1.4 The deformation of the castings is allowed to be corrected; after correction, the castings shall be subjected to stress relief treatment.
5.2 Repair welding
Contents
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Grade
5 Manufacturing
6 Technical requirements
7 Test methods
8 Inspection rules
9 Marking, quality certificate, packaging, transportation and storage
Annex A (Normative) Requirements for carbon equivalent
Figure 1 Type of separated test bar of casting
Table 1 Grade and chemical composition of castings
Table 2 Mechanical properties at room temperature
Table 3 Sampling requirements
Table 4 Judgment rules
Table A.1 Carbon equivalent
