Stainless steel pipe is a hollow long round profile, which is widely used in industrial pipelines and mechanical structural parts such as petroleum, chemical, medical, food, light industry, mechanical instruments, etc. At the same time, because it is light in weight with the same bending and torsional strength, it is also often used to manufacture mechanical parts and engineering structures. In addition, it can also be used as architectural decoration materials such as railings and guardrails. According to the production method, stainless steel pipes can be divided into two categories: seamless pipe and welded pipe. Seamless stainless steel pipes are manufactured by perforation, hot rolling or cold drawing, and have high pressure resistance and mechanical strength. They are suitable for high temperature and high pressure environments, such as oil and natural gas transportation, boilers and chemical equipment. Seamless pipes can be further divided into hot-rolled pipes, cold-rolled pipes, cold-drawn pipes and extruded pipes. Among them, cold drawing and cold rolling processes can improve the dimensional accuracy and surface quality of steel pipes. Welded pipes are welded from stainless steel plates into pipes. According to the welding seam method, they can be divided into straight seam welded pipes and spiral welded pipes. They are mainly used in fluid transportation, architectural decoration and structural support.