Cold and hot rolled steel plate difference

Hot rolling

Hot rolling is based on slabs (mainly continuous casting billets), which are heated to form strips from roughing mills and finishing mills. The hot steel strip from the last rolling mill of the finishing mill is cooled to a set temperature by laminar flow, rolled into a steel coil by a coiler, and the cooled steel coil is subjected to different finishing operations according to different needs of users. Lines (flat, straight, cross-cut or slit, inspection, weighing, packaging and marking) are processed into steel, flat and slit steel strips. To put it simply, a billet is finely rolled after being heated (that is, the red hot, hot steel block in the TV), and then trimmed and corrected to become a steel plate. This is called hot rolling.

Cold rolling

Cold rolling: hot-rolled steel coil is used as raw material, and the scale is removed by pickling, followed by cold continuous rolling. The finished product is rolled hard roll. The cold work hardening caused by continuous cold deformation makes the hardness and hardness of the rolled hard roll rise and tough. The plastic index is reduced, so the stamping performance will deteriorate and can only be used for parts that are simply deformed. Rolled hard rolls can be used as raw materials for hot-dip galvanizing plants because the hot-dip galvanizing units are provided with an annealing line. The rolled hard coil weight is generally 6 to 13.5 tons, and the coil is continuously rolled at a normal temperature. The inner diameter is 610mm.

Product features: Because it has not been annealed, its hardness is very high (HRB is greater than 90), and the machining performance is extremely poor. Only a simple directional bending process of less than 90 degrees (perpendicular to the winding direction) can be performed.

To put it simply, cold rolling is processed and rolled on the basis of hot rolled coils, generally in the hot rolling--- pickling---cold rolling process.

Cold rolling is processed from hot-rolled sheets at room temperature, although the steel sheet is heated during the processing because of rolling, although it is called cold rolling. Due to the cold rolling of hot rolling through continuous cold deformation, the mechanical properties are relatively poor and the hardness is too high. It must be annealed to restore its mechanical properties. Rolled hard rolls are generally used for products that do not require bending or stretching. The thickness of 1.0 or less is hard and good for both sides or four sides.

1. Cold rolling is processed from hot rolled sheet at room temperature.

2. After a piece of billet is heated (that is, the burning red and hot steel block in the TV), it is refined by several rolling, and then cut and trimmed to become a steel plate. This is called hot rolling.