Coils (hot rolled coil) is a slab (mainly billet) as raw material, heated by a roughing mill and finishing mill group made of steel. From finishing the last one out of the hot strip mill by laminar cooling to the set temperature, the coiling machine rolled into steel rolls, steel strip coils cooled, depending on the needs of users, through various finishing operations line (smooth, straightening, transverse or longitudinal, inspection, weighing, packaging and signs, etc.) processing and become steel, flat steel product volume and slitting. As the hot rolling steel products with high strength, good toughness, easy molding excellent performance and good weldability, etc., which are widely used in coil ships, automobiles, bridges, buildings, machinery, pressure vessels and other manufacturing industries.