Improve the surface roughness, improve the quality of the fit, reduce wear and extend the service life of the parts, but the processing costs of the parts are reduced. Hot-rolled precision steel pipes use continuous casting round tube billet slabs or blooming slabs as raw materials, heated by a walking heating furnace , high-pressure water descaling, and then enter the rough rolling mill, and the rough rolling material enters the finishing mill after cutting the head, tail, and , Implementation of computer-controlled rolling, after the final rolling, it will undergo laminar cooling and coiling by a coiler to become a straight hair coil. The head and tail of straight hair curlers are often tongue-shaped and fish-tail-shaped, with poor thickness and width accuracy, and the edges often have defects such as wave shape, hemming, and tower shape. The weight of the straight hair coil is heavier. After the straight hair coil is processed by the finishing line such as head cutting, tail trimming, edge trimming, and multi-pass straightening, flattening, and then cutting or recoiling, it becomes: hot-rolled steel plate, flattening Hot-rolled steel coils, slitting strips and other products. If the hot-rolled finished coil is pickled to remove the oxide scale and coated with oil, it will become a hot-rolled pickled coil.