Cold rolled steel is steel produced by cold rolling. Cold rolling is to further thin the No. 1 steel sheet to a target thickness under room temperature conditions. Compared with hot-rolled steel sheets, cold-rolled steel sheets are more accurate in thickness, and have a smooth and beautiful surface. At the same time, they also have various superior mechanical properties, especially processing properties. Because cold-rolled raw coils are relatively brittle and hard, and not suitable for processing, cold-rolled steel sheets are usually required to be annealed, pickled and surface smoothed before being delivered to customers. The maximum thickness of cold-rolled steel is 0.1-8.0mm or less. For example, the thickness of cold-rolled steel plate in most factories is less than 4.5mm; the minimum thickness and width are determined according to the equipment capacity of each factory and market demand.
The difference between cold-rolled steel and hot-rolled steel is not in the smelting process, but in the rolling temperature, or the end temperature of the rolling. The final rolling temperature is lower than the recrystallization temperature of the steel to become cold rolled steel. Hot-rolled steel is easy to roll, and the rolling efficiency is high, but the steel is oxidized under hot-rolling conditions, and the surface of the product is dark and gray. Cold-rolled steel requires high rolling mill power and low rolling efficiency. In order to eliminate work hardening during the rolling process, intermediate annealing is required, so the cost is also high. However, cold-rolled steel has a bright surface and good quality and can be directly used for processing. Finished products, so cold rolled steel sheets are widely used.
