Hot-rolled precision steel tube is made of continuous casting round tube slab or blooming slab, heated by walking-beam heating furnace, descaling by high pressure water and entering rough rolling mill. Rough rolling material is cut, tailed and re-entered into finishing mill. Computer controlled rolling is implemented. After finishing rolling, it is cooled by laminar flow and coiled by coiler and becomes direct hair coil. The head and tail of straight hair curls are usually tongue-like and fish-tail-like, and the accuracy of thickness and width is poor. The edges of straight hair curls are often corrugated, folded and tower-shaped. The coil weight is heavy and the inner diameter of the coil is 760 mm. After the straight hair coil is treated by cutting head, cutting tail, trimming edge, multi-pass straightening and leveling, and then cut or re-coil, it becomes hot rolled steel plate, flat hot rolled steel coil, longitudinal cut strip and other products. Hot-rolled finish coil will be hot-rolled pickled coil if the oxide scale is removed by pickling and oiled.