Circular steel pipe is both openings and have hollow concentric sections of steel larger than the surrounding. The specifications of steel pipes are indicated by appearance dimensions and inner diameter and wall thickness, with a wide range of dimensions from very small diameter capillary to large round steel pipe of several meters in diameter. Round steel pipes can be used for pipelines, thermal equipment, machinery industry, petroleum geological drilling, containers, chemical industry, and special uses. It can be divided into seamless, ERW, LSAW, SSAW steel pipe according to the production process.