Hot rolled coil 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 a steel coil by a coiler, cooled steel strip, and subjected to different finishing operations according to the different needs of the user Line (flattening, straightening, crosscutting or slitting, inspection, weighing, packaging and marking, etc.) and become steel plate, flat roll and longitudinal steel products. Simply put, a piece of billet in the heat (that is, the kind of burning red hot steel blocks) after a few rolling, and then trimming, correction of steel, this is called hot rolling.
Cold rolled steel coil: hot rolled coil as raw material, pickling to remove the scale after the cold rolling, the finished product for the hard rolling, due to continuous cold deformation caused by cold hardening hard rolling strength, hardness, toughness Plastic index drops, so stamping performance will deteriorate, can only be used for simple deformation of the parts. Rolling hard rolls can be used as raw materials for hot-dip galvanizing plants, since hot-dip galvanizing units are equipped with annealing lines. Rolling hard roll 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 put, cold rolling is hot rolled coil based on the processing of rolling out, in general, is hot rolling --- pickling --- cold rolling such processing.
Cold rolling is at room temperature from the hot-rolled plate processing, although in the process because the rolling will make the plate temperature, although it is 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. Must be annealed to restore its mechanical properties, no annealing is called rolling hard roll. Rolling rolls are generally used for products that do not require bending or stretching.
Cold rolled sheet steel products are used in a wide variety of end applications such as: appliances,automobiles, electric motors, plumbing fixtures, drum manufacturing, shelving, furniture, doors, toolboxes, tubing products.