Cold Rolled Coil Steel
What Is Cold Rolled Coil Steel
Cold rolled steel is steel produced by cold rolling. Cold rolling is to further thin the steel plate to a target thickness at room temperature. Compared with hot-rolled steel plates, cold-rolled steel plates have a more precise thickness, smooth and beautiful surface, and have various superior mechanical properties, especially in terms of processing performance.
Because cold-rolled raw coils are relatively brittle and hard and not suitable for processing, cold-rolled steel plates are usually required to be annealed, pickled and surface smooth before being handed over to customers. The maximum thickness of cold rolling is 0.1–8.0MM or less. For example, the thickness of cold-rolled steel plates in most factories is less than 4.5MM. The minimum thickness and width are determined according to the equipment capabilities and market demand of each factory.
Hot-rolled steel coils are used as raw materials, and the oxide scale is removed by pickling and then cold-rolled continuously. The finished product is hard-rolled coils. Due to the cold work hardening caused by continuous cold deformation, the strength and hardness of the hard-rolled coils increase, and the toughness and plasticity index decreases. , so the stamping performance will deteriorate and can only be used for parts with simple deformations. Hard rolled coils can be used as raw materials in hot-dip galvanizing plants because hot-dip galvanizing units are equipped with annealing lines. The weight of hard-rolled coils is generally 6 to 13.5 tons. The steel coils are continuously rolled on the hot-rolled pickled coils at room temperature. The inner diameter is 610mm.
Cold Rolled Coil VS Hot Rolled Coil
The difference between cold-rolled steel and hot-rolled steel is not in the smelting process but in the rolling temperature, or the rolling termination temperature. If the final rolling temperature is lower than the recrystallization temperature of the steel, it becomes cold rolled steel. Hot-rolled steel is easy to roll and has high rolling efficiency. However, the steel is oxidized under hot-rolling conditions and the surface of the product is dark gray and dull. Cold-rolled steel requires high-power rolling mills and low rolling efficiency. In addition, intermediate annealing is required during the rolling process to eliminate work hardening, so the cost is higher. However, cold-rolled steel has a bright surface and good quality and can be directly used for processing. Finished products, so cold rolled steel plates are widely used.