Cold rolling is to further thin the steel plate to the target thickness below the recrystallization temperature at room temperature. Compared with hot-rolled steel plate, the thickness of cold-rolled steel plate is more accurate, and the surface is smooth and beautiful. Generally, there is no heating process for cold rolled plate before rolling. However, due to the small thickness of the strip steel, the flatness problem is easy to occur.

Cold rolled plate, therefore, in order to control the size accuracy and surface quality of the strip steel, many complicated processes are used. The cold rolling production line is long, the equipment is many, and the process is complex. With the improvement of users' requirements for strip size accuracy, shape and surface quality, there are more control models, l1 and l2 systems and shape control methods for Cold rolled plate cold rolling mill than for hot rolling mill. Moreover, the temperature of rolls and strips is also one of the more important control indicators. By definition, ingots or billets are difficult to deform and process at room temperature, and most steels are rolled by hot rolling.

Because iron oxide scale is easily generated on the surface of steel at high temperature, which makes the surface of hot rolled steel rough and the size fluctuates greatly, the steel with smooth surface, accurate size and good mechanical properties is required to be produced by cold rolling using hot rolled semi-finished products or finished products as raw materials.