1 The subject content and scope of application
The national standard prescribed the product classification, dimension, shape, weight, technical requirement, testing method, regulations of acceptance, packing, label and quality certificate for longitudinal electric resistance welded steel tube.
The national standard is suitable for different kinds of structural members, parts and conveyance fluid pipes and electric resistance welded steel tubes for other purposes.
2 Cited standards
GB 222 The sampling method for steel chemical analysis and allowable deviation for chemical analysis of finished products
GB 223 Methods for chemical analysis of iron, steel and alloy
GB 228 Test method for metal tensile strength
GB 241 Metal tubes—Hydrostatic pressure testing
GB 242 Method for flaring test on tubes of metals
GB 244 Method for bend test on tubes of metals
GB 246 Metallic materials-Tube-Flattening test
GB 699 Quality carbon structure steel--Technical requirements
GB 700 Carbon structural steel
GB 2102 Acceptance, packing, marking and certification of pipe
GB 2975 Sampling regulations on steel products mechanics and technical performance test
GB 6397 Metallic materials--Test pieces for tensile testing
GB 7735 Steel tubes--The inspection method on eddy current test
3 Classification and code name
3.1 The steel tubes can be divided into the following according to manufacturing precision:
The outer diameter high-precision steel tube D1
The outer diameter higher-precision steel tube D2
Outer diameter general precision steel tube D3
Wall thickness high-precision steel tube S1
Wall thickness higher-precision steel tube S2
Wall thickness general precision steel tube S3
3.2 The steel tubes can be divided into the following material status:
Soft state steel tube R
Low-hard state steel tube DY
