Seamless steel pipe is a kind of hollow cross-section with no surrounding joints. It can be used for transmitting a large number of fluid. Such as oil, natural gas, water and some solid materials. At the same time it can be widely used as the manufacture of various structural parts and mechanical parts, such as the drill pipe, automotive transmission shaft, as well as building construction. Compared with the solid steel such as round bar, at the same flexural torsional strength, the weight of Seamless steel pipe is more light.

It is an type of economic steel.