The hot rolling hydraulic cylinder pipe is made of continuous casting round billet slab or initial rolled slab as raw material, heated by step heating furnace, descaled by high-pressure water and then into rough rolling mill. The rough rolling material passes through the cutting head, tail and then into the finishing mill. The computer controlled rolling is carried out, and after the final rolling, the laminar cooling and the coiler are taken up to form a straight hair roll. The head and tail of the straight hair roll are often in the shape of a tongue and a fishtail. The thickness and width are poorly accurate, and the side has frequent defects such as a wave shape, a folded edge, and a tower shape. The weight of the coil is heavier and the inner diameter of the coil is 760 mm. After straightening the straight hair through the cutting, cutting, trimming and multi-pass straightening, leveling and other finishing lines, and then cutting or rewinding, it becomes: hot-rolled steel sheet, flat hot-rolled steel coil, vertical Cut the belt and other products. If the hot-rolled finishing roll is pickled to remove the scale and oiled, the hot-rolled pickled sheet roll is formed.