1. Hot Rolled

The continuous casting slab or primary rolling slab is used as raw material, heated by stepping furnace, dephosphorized by high pressure water and then entered into roughing mill. The roughing material enters finishing mill after cutting head and tail, and then carried out computer controlled rolling. After the final rolling, it passes through laminar cooling (computer controlled cooling rate) and coiler to become straight hair coil. The head and tail of straight hair coil are often tongue and fishtail, and the accuracy of thickness and width is poor. The side part often has defects such as wave shape, folding edge and tower shape. The coil is heavy and the inner diameter of the steel coil is 760mm. (The general pipe industry likes to use.) After cutting head, cutting tail, cutting edge, straightening, leveling and other finishing line treatment, cutting plate or rewinding, it becomes: hot rolled steel plate, flat hot rolled steel coil, longitudinal cutting tape and other products. Hot rolled finish roll is hot rolled pickling plate roll after pickling removing the oxide scale and oiling.

2. Cold Rolled

The hot rolled steel coil is used as raw material, and the oxide scale is removed after pickling. The finished product is rolled hard coil. Due to the cold working hardening caused by continuous cold deformation, the strength and hardness of rolled hard coil increase, the toughness and plastic index decrease, and the stamping performance deteriorates, so it can only be used for simple deformation parts. Hard roll can be used as raw material for hot-dip galvanizing plant, because hot-dip galvanizing unit is set with quenching line. The weight of rolled hard coil is generally 6~13.5 tons, and the inner diameter of steel coil is 610mm. Generally, continuous annealing (CAPL unit) or cover furnace should be used to remove annealing treatment for cold work hardening and rolling stress, and achieve the mechanical properties specified in the standard. The surface quality, appearance and dimensional accuracy of cold-rolled steel plate are better than those of hot-rolled steel plate.