The hot-rolled cylinder tube uses continuous casting round tube billet slabs or primary rolling slabs as raw materials, and is heated by a stepping furnace. After descaling with high-pressure water, it enters the roughing mill. The computer controlled rolling is adopted, and after finishing rolling, it is coiled by laminar flow cooling and coiler to become a straight hair coil. The head and tail of straight hair curls are often tongue-shaped and fish-tailed, with poor thickness and width accuracy, and often have defects such as wave shape, hemming, and tower shape at the edges. The coil is heavier and the inner diameter of the steel coil is 760mm. After the straight hair roll is processed by finishing lines such as head cutting, tail cutting, edge trimming and multi-level straightening and smoothing, and then cut or re-rolled, it becomes: hot-rolled steel plate, flat hot-rolled steel coil, longitudinal Cut tape and other products. If the hot-rolled finishing coil is pickled to remove scale and coated with oil, it will become a hot-rolled pickled coil.