Classification of stainless steel pipes: stainless steel seamless steel pipes and stainless steel welded steel pipes (seam steel pipes) are two basic categories. According to the outer diameter of the steel pipe, it can be divided into round pipes and special-shaped pipes. Round steel pipes are widely used, but there are also some square, rectangular, semi-circular, hexagonal, equilateral triangle, octagonal and other special-shaped steel pipes.

For steel pipes under fluid pressure, hydraulic test and radiographic testing must be carried out to check their pressure resistance and quality. No leakage, wetting or expansion under the specified pressure is qualified. Some steel pipes must be carried out according to the standard or the demander’s requirements. Crimping test, flaring test, flattening test, etc.

Seamless stainless steel pipe, also called stainless steel seamless pipe, is made of steel ingots or solid pipe billets through perforation and then made by hot rolling, cold rolling or cold drawing. The specifications of seamless steel pipes are expressed in millimeters of outer diameter * wall thickness.