What is the Difference of Hot Rolled Plate and Cold Rolled Plate

Hot Rolled Plate
Hot rolling is based on slab (mainly continuous casting slab) as raw material, after heating by the roughing mill and finishing mill made of strip. The hot steel strip from the final rolling mill is cooled to a set temperature by laminar flow, rolled into steel coil by coiler. After the steel strips being cooled and according to the different needs of the user, the steel coils will throught different finishing lines (flattening, straightening, crosscutting or slitting, inspection, weighing, packaging and marking, etc.) and become steel plate, flat roll and longitudinal steel products. Simply to say, a piece of billet being heated (that is, the kind of burning red hot steel blocks seen in TV) and after a few rolling, and then trimming, correction and finally become to be steel plate, this is called hot rolling.
Cold Rolled Plate
Cold rolling is use hot rolled coil as raw material, pickling to remove the scale and then go through the cold continuous rolling, due to continuous cold deformation caused by cold hardening hard rolling strength, hardness, toughness Plastic index drops, so stamping performance will deteriorate, it can only be used for simple deformation of the parts. Cold rolling is a steel sheet in which the steel sheet is further rolled to a desired thickness at room temperature under the recrystallization temperature. Compared with hot-rolled steel, cold-rolled steel plate thickness is more accurate, and the surface is smooth and beautiful. Full hard coil weight is generally 6 to 13.5 tons, coil at room temperature, hot rolling acid scrubbing continuous rolling. The inner diameter is 610mm. Features: Because it has not been annealed, its hardness is very high (HRB greater than 90), mechanical processing performance is very poor, only a simple directional less than 90 degrees of bending (perpendicular to the coiling direction).Simply to say, cold rolling is hot rolled coil based on the processing of rolling out, in general, its production process is hot rolling --- pickling --- cold rolling. Cold rolling is at room temperature from the hot-rolled plate processing, although in the process because the rolling will make the plate temperature rise, it is still called cold rolling. As a result of hot rolling through continuous cold deformation of the cold rolling, the mechanical properties are relatively poor, the hardness is too high. It must be annealed to restore its mechanical properties, the coil without annealing is called full hard coil. Full hard coil are generally used for products that do not require bending or stretching.