Seamless steel pipe is perforated by the whole round steel, and the steel pipe with no weld on the surface is called seamless steel pipe. According to the production method, the seamless steel pipe can be divided into hot-rolled seamless steel pipe, cold-rolled seamless steel pipe, cold-drawn seamless steel pipe, extruded seamless steel pipe, pipe jacking and so on. According to the section shape, the seamless steel pipe is divided into two kinds of round and shaped, shaped pipe has square, oval, triangle, hexagonal, melon seed, star, fin tube and many complex shapes. The maximum diameter is 900mm and the minimum diameter is 4mm. According to different uses, there are thick wall seamless steel pipes and thin wall seamless steel pipes. Seamless steel pipe is mainly used for petroleum geological drilling pipe, petrochemical cracking pipe, boiler pipe, bearing pipe and high-precision structural steel pipe for automobiles, tractors and aviation.