Stainless steel pipe is a kind of hollow long round steel, mainly widely used in petroleum, chemical, medical, food, light industry, mechanical instrumentation, and other industrial transmission pipelines and mechanical structural parts, etc. In addition, when the bending and torsion strength is the same, the weight is lighter, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also commonly used as furniture and kitchenware, etc. It can be divided into oil well pipe (casing, oil pipe, drill pipe, etc.), pipeline pipe, boiler pipe, mechanical structure pipe, hydraulic pillar pipe, gas cylinder pipe, geological pipe, chemical pipe (high-pressure fertilizer pipe, petroleum cracking pipe) and marine pipe, etc. by application.