Seamless steel pipe standards are technical specifications for the manufacture and application of seamless steel pipes, covering hot rolling (extrusion) and cold drawing (rolling) processes. They are divided into 18 application types, including structural, fluid transport, and boiler applications, corresponding to national standards such as GB/T 8162 (structural) and GB 5310 (high-pressure boiler). Materials include carbon steel, alloy steel, and stainless steel. National standard GB/T 17395, drafted by Panzhihua Iron & Steel Group Chengdu Iron & Steel Co., Ltd. and other units, was revised in 2008, replacing the 1998 version. It specifies technical parameters such as outer diameter classification, permissible deviations, weight, and length of steel pipes, integrating ISO international standards and adding commonly used domestic specifications.
The standard classifies outer diameter series into three categories: standardized, non-standardized, and special-purpose. Standardized deviations are preferred for permissible deviations, and the upper limit of steel pipe length is extended to 12500 mm. Cold-drawn seamless steel pipes with irregular wall thicknesses, including those with equal wall thicknesses, unequal wall thicknesses, and variable diameter sections, must undergo appearance and dimensional inspection according to the standard to ensure quality. The standards system also covers specialized fields such as ships and automobiles, involving specifications such as GB/T 5312 (for ships) and GB 3088 (for automobile half-shaft sleeves).
