GB/T 45781-2025Seamless steel tubes for mechanical structures (English PDF)
结构用机加工无缝钢管
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Issued by
SAMR; SAC
Level / Type
National · Recommended
Issue date
June 30, 2025
Implementation date
January 1, 2026
Scope
GB/T 45781-2025 is the English-translated version of 结构用机加工无缝钢管.
GB/T 45781-2025 is the Chinese national standard covering seamless tube bought as stock to be machined into parts — the order content and the manufacturing process, the steel grades and their chemical composition, the tensile, impact and hardness properties, the non-metallic inclusion rating and the ultrasonic or eddy current testing that finds the flaw before the metal around it is cut away, the dimensions and tolerances, and the inspection rules. First edition, under the China Iron and Steel Association. In force from 1 January 2026. Issued on 30 June 2025, it has been in force since 1 January 2026.
Document preview — GB/T 45781-2025
National Standard of the People's Republic of China
- ICS
- 77.140.75
- Classification
- H 48
Issued by: State Administration for Market Regulation; Standardization Administration of the PRC
Contents
- PrefaceIII
- 1 Scope1
- 2 Normative references1
- 3 Terms and Definitions2
- 4 Order Content2
- 5 Manufacturing Process2
- 6 Technical Requirements3
- 7 Test methods14
- 8 Inspection Rules15
- 9 Packaging, marking and quality certificate15
Foreword
This document is in accordance with the provisions of GB/T 1.1-2020 "Guidelines for standardization work Part 1: Structure and drafting rules for standardization documents" Drafting.
Please note that some of the contents of this document may involve patents. The issuing organization of this document does not assume the responsibility for identifying patents.
This document was proposed by the China Iron and Steel Association.
This document is under the jurisdiction of the National Technical Committee on Steel Standardization (SAC/TC183).
This document was drafted by: Zhejiang Minghe Steel Pipe Co., Ltd., Hengyang Valin Steel Pipe Co., Ltd., Jingjiang Special Steel Co., Ltd., Changsha Dali Steel Co., Ltd.
Shen Hydraulic Engineering Co., Ltd., Zhejiang Taifu Seamless Steel Pipe Co., Ltd., Chongqing Liwan Precision Parts Co., Ltd., Chengde Jianlong Special Steel Co., Ltd.
Company, Linyi Jinzhengyang Pipe Industry Co., Ltd., Wuxi Beilai Steel Pipe Co., Ltd., Daye Special Steel Co., Ltd., Linzhou Fengbao Pipe Industry Co., Ltd.
Company, Zhejiang Huachang Hydraulic Machinery Co., Ltd., Zhejiang Honghai Steel Pipe Manufacturing Co., Ltd., Dexin Steel Pipe (China) Co., Ltd., Metallurgical Industry Information Standards Research Institute.
The main drafters of this document are: Fu Guozhu, Zheng Yuanhong, Li Dingjie, Liu Jilin, Su Chunyang, You Hao, Wang Zheng, Ni Zhihong, Bian Shouhai, Hu Shunzhen, Zhi Xiangdong, Li Gang, Li Jingmin, Wu Feng, Fan Dingze, Wang Honghai, Li Qi, Peng Yang, Yao Yong, Yu Jiaheng, Liu Qiang, Fei Xingang, Yang Qiang, Hu Xiaojun, Cui Tao, Xia Wenbin, Niu Liang, Guo Bicheng, and Wang Tiantian.
Machined seamless steel pipes for structural use
1 Scope
This document specifies the ordering content, manufacturing process, technical requirements, test methods, inspection rules, packaging, Logo and quality certificate.
This document applies to seamless steel tubes for machining machinery parts (hereinafter referred to as "steel tubes").
2 Normative references
GB/T 222
GB/T 223.5
GB/T 223.9
GB/T 223.11
GB/T 223.14
GB/T 223.19
GB/T 223.23
GB/T 223.26
GB/T 223.37
GB/T 223.40
GB/T 223.59
GB/T 223.63
GB/T 223.78
GB/T 223.84
GB/T 223.85
GB/T 223.86
GB/T 228.1
GB/T 229
GB/T 231.1
GB/T 699
GB/T 2102
GB/T 2975
GB/T 3077
GB/T 4336
GB/T 5777
GB/T 7735
GB/T 10561-2023
......
This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 20 pages — is available in the English PDF.
Referenced standards
Normative references
- GB/T 222Steels and alloys - Permissible deviations of product analyzed chemical composition
- GB/T 223.23Iron, steel and alloy - Determination of nickel content - The dimethylglyoxime spectrophotometric method
- GB/T 223.26Iron, steel and alloy - Determination of molybdenum content - The thiocyanate spectrophotometric method
- GB/T 223.40Iron, steel and alloy - Determination of niobium content - The sulphochlorophenol S spectrophotometric method
- GB/T 223.59Iron,steel and alloy - Determination of phosphorus content - Bismuth phosphomolybdate blue spectrophotometric method and antimony phosphomolybdate blue spectrophotometric method
- GB/T 228.1Metallic Materials — Tensile Testing — Part 1: Method of Test at Room Temperature
GB/T 223.5 · GB/T 223.9 · GB/T 223.11 · GB/T 223.14 · GB/T 223.19 · GB/T 223.37 · GB/T 223.63 · GB/T 223.78 · GB/T 223.84 · GB/T 223.85 · GB/T 223.86 · GB/T 5777 · GB/T 7735 · GB/T 10561-2023
Editions of GB/T 45781
| Edition | Title | Revision | Status |
|---|---|---|---|
| GB/T 45781-2025 | Seamless steel tubes for mechanical structures | current edition | Current |
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