Seamless steel pipe is made of a whole piece of metal with no seams on the surface, which is called seamless steel pipe. According to the production method, seamless pipes are divided into heat pipes, cold-rolled pipes, cold-drawn pipes, extruded pipes and pipe jacking.
According to the cross-sectional shape, seamless steel pipes are divided into two types: round and special-shaped. Special-shaped tubes have many complex shapes, such as square, oval, triangle, hexagon, melon seeds, star and finned tubes. The maximum diameter is 650 mm and the minimum diameter is 0.3 mm.
Seamless steel pipes are widely used. Universal seamless steel pipe is rolled from ordinary carbon structural steel, low alloy structural steel or alloy structural steel, with the largest output, and is mainly used as pipes or structural parts for conveying fluids.