The difference between cold rolled plate and hot rolled plate Hot rolled plate, the rolling temperature is high, so the deformation resistance is small, can achieve large deformation. Taking the rolling of steel plate as an example, the general thickness of continuous casting billet is about 230mm, and after roughing and finishing, the final thickness is 1~20mm. At the same time, due to the small width and thickness ratio of steel plate, the dimensional accuracy requirement is relatively low, and the shape problem is not easy to occur, so the crown is mainly controlled. For the organization of the requirements, generally through the control rolling control cold to achieve. Cold rolled plate, generally in the opening before the heating process is not. However, due to the small thickness of the strip, it is easy to appear plate shape problems. Moreover, the cold rolled strip is the finished product, so in order to control the size accuracy and surface quality of the strip, a lot of very complicated process is adopted. Cold rolling has long production line, many equipment and complicated process. With the improvement of customers' requirements for strip size accuracy, strip shape and surface quality, there are more control models, L1 and L2 systems and strip shape control methods in cold rolling mill than in hot rolling mill. Moreover, the temperature of the roll and the strip is also one of the more important control indexes. By definition, the ingot or billet at room temperature is difficult to deformation, not easy to process, generally heated to 1100 ~ 1250℃ for rolling, this rolling process is called hot rolling. Most steel is rolled by hot rolling. However, because the surface of steel is easy to form oxide scale at high temperature, which makes the surface of hot-rolled steel rough and the size fluctuates greatly, it is required that the steel with smooth surface, precise size and good mechanical properties should be produced by cold rolling with hot-rolled semi-finished products or finished products as raw materials. Rolling at room temperature is generally understood as cold rolling. From the point of view of metalology, the boundary between cold rolling and hot rolling should be distinguished by recrystallization temperature. That is, the rolling below the recrystallization temperature is cold rolling, and the rolling above the recrystallization temperature is hot rolling. The recrystallization temperature of steel is 450 ~ 600℃. To put it simply:. 1. The surface of the cold-rolled plate has a certain gloss and feels smooth, similar to the common steel cup used for drinking water. 2. Hot rolled plate, if not pickled, is similar to the surface of many ordinary steel plates on the market. The rusty surface is red, and the rusty surface is purplish black (oxide). The advantages of cold-rolled plate and hot-rolled plate are as follows: 1. Higher accuracy. The thickness difference of cold-rolled strip is not more than 0.01~0.03mm. 2, the size is thinner, the thin cold rolled steel strip can be rolled 0.001mm; Hot rolling is now as thin as 0.78mm. 3, the surface quality is better, cold rolled steel plate can even produce mirror surface; And the surface of the hot rolled plate has iron scale, pitting and other defects. 4, cold rolled sheet can be adjusted according to user requirements of its mechanical properties such as tensile strength and process properties such as stamping performance. Cold rolling and hot rolling are two different steel rolling technology, as the name suggests, cold rolling is in the steel at room temperature, the hardness of the steel is large. Hot rolling is when steel is rolled at high temperature.