Steel pipe has two kinds of carbon steel pipe and stainless steel pipe .It is a kind of hollow long round steel. Steel pipe is widely used in industrial transmission pipelines and mechanical structural components such as petroleum, chemical industry, medical treatment, food, light industry, machinery and instruments, etc. In addition, when the bending and torsional strength are the same, the weight is light, so it is also widely used in the manufacture of mechanical parts and engineering structures. It is also commonly used as furniture, kitchenware, etc.

The first stage is blanking. Steel pipe elbow materials are usually carbon pipes, stainless steel plates and stainless steel rods. The shape, size, and other requirements of the blank parts can also be met according to the process specifications of different products. Heating and welding are commonly used in the molding process. The third stage is the heat treatment, which is an important part of the production of steel and stainless steel elbows. The fourth stage is surface treatment. The fifth stage is the cutting process.

The sixth stage is nondestructive testing, which is an important process to detect possible defects in stainless steel and elbow machining.  The seventh stage is the surface treatment using the pickling method on the stainless steel elbow. The main purpose of surface protection of stainless steel elbow is to prevent corrosion and obtain the appearance of the product.