Seamless steel pipe is made of a whole round steel through holes. There is no weld on the surface of the steel pipe, which is called seamless steel pipe. According to the production method, 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, jacking pipe, etc. According to the cross-sectional shape, seamless steel pipe is divided into round and special-shaped. Special-shaped pipes have square, oval, triangle, hexagon, melon seed, star, winged pipe and many other complex shapes. The maximum diameter is 900mm and the minimum diameter is 4mm. According to different uses, there are thick-walled seamless steel pipes and thin-walled seamless steel pipes. Seamless steel pipes are mainly used as petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler pipes, bearing pipes, and high-precision structural steel pipes for automobiles, tractors, and aviation.