Cold rolled steel is steel produced by cold rolling. Cold rolling is a steel sheet obtained by further reducing the No. 1 steel sheet to a target thickness under room temperature conditions. Compared with hot-rolled steel, cold-rolled steel has a more precise thickness, a smooth and beautiful surface, and also has various superior mechanical properties, especially in terms of processability. Because cold-rolled raw coils are brittle and hard, they are not suitable for processing, and cold-rolled steel sheets usually need to be annealed, pickled and surface smoothed before being delivered to customers. The maximum thickness of cold rolling is below 0.1–8.0MM. For example, the thickness of cold-rolled steel plate in most factories is below 4.5MM; the minimum thickness and width are determined according to the equipment capacity and market demand of each factory.
The difference between cold-rolled steel and hot-rolled steel is not the smelting process, but the rolling temperature, or the end temperature of rolling. Cold rolled steel means that the finishing temperature is lower than the recrystallization temperature of the steel. Hot-rolled steel is easy to roll and has high rolling efficiency, but under hot-rolled conditions, the steel is oxidized and the surface of the product is dark gray. Cold-rolled steel requires high rolling mill power and low rolling efficiency. Intermediate annealing is required to eliminate work hardening during the rolling process, 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.
The hot-rolled steel coil is used as the raw material, after pickling to remove the oxide scale, the cold continuous rolling is carried out, and the hard coil is rolled. Cold work hardening induced by continuous cold deformation increases the strength, hardness, toughness and plasticity index of rolled hard coils. , so the stamping performance will be poor, and it can only be used for parts with simple deformation. Hard rolled coils can be used as raw material in hot dip galvanizing plants because hot dip galvanizing lines are equipped with annealing lines. The weight of the rolled hard coil is generally 6~13.5 tons, and the hot-rolled pickled coil is continuously rolled at room temperature. The inner diameter is 610mm.
Post time: Nov-14-2022