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Cold rolled steel plate difference
Jun 01, 2018

Hot rolled

Hot rolling, with slab (mainly continuous casting billet) as raw material, is made of strip steel by roughing mill and precision mill group after heating. From finishing the last hot steel strip mill out through laminar flow cooling to the set temperature, which consists of the winder coil, steel coil after cooling, according to the different needs of users, with different finishing line (flat, straightening, transverse or longitudinal cutting, inspection, weighing, packaging and logo, etc.) and become a steel plate, flat roll and longitudinal cutting steel strip products. To put it simply, a billet is rolled over several times after being heated (that is, a red-hot piece of steel like the one on TV) and then cut the edges to make a steel plate. This is called hot rolling.

Cold rolled

Cold-rolled, hot-rolled steel coil for raw material, after acid pickling to remove oxide skin for cold rolling, the finished product is hard, because of cold work hardening caused by deformation of continuous cold rolling hard roll strength, increase hardness, toughness and plastic index decreased, so the stamping performance will deteriorate, can only be used for simple deformation of the parts. The rolled coil can be used as raw material for hot galvanizing factory, because the hot galvanizing unit is equipped with annealing line. The rolled coil weight is usually 6~13.5 tons, and the rolled coil is continuously rolled at room temperature. The inside diameter is 610mm.

Product features: because there is no after annealing treatment, the hardness is very high (HRB is greater than 90), mechanical processing performance is poor, only simple has directivity of less than 90 degree bend processing (perpendicular to the direction of the winding).

In a nutshell, cold rolling is the process of rolling on the basis of hot rolled sheet rolls. Generally speaking, it is the process of hot rolling -- pickling -- cold rolling.

Cold rolling is made from hot rolled sheet at room temperature, although it is also called cold rolling because it heats up the steel sheet. The cold rolling formed by continuous cold deformation of hot rolling has poor mechanical performance and high hardness. It must be annealed before its mechanical properties can be restored. Rolled coils are generally used to make products that do not require bending or stretching.