What Is The Difference Between Cold Rolled Steel And Hot Rolled Steel?

First we need to know the difference between hot rolling and cold rolling.

1. Appearance and surface quality: Since the cold plate is obtained after the hot rolling process, and cold rolling will also perform some surface finishing, the cold plate is better than the hot plate in terms of surface quality (such as surface roughness). Comes well, so if there is a higher requirement for the coating quality of the product, such as subsequent painting, generally choose a cold plate, and the hot plate is divided into pickled and un-pickled boards. The surface of the pickled board is acidified Normal metallic color, but the surface is still not as cold as the cold rolled plate. The non-acid-washed plate usually has an oxide layer on the surface, it is black, or there is a black iron iron oxide layer. Generally speaking, it is fire-baked. And, if the storage environment is not good, it will usually bring a little embroidery.

2. Performance: In general, the mechanical properties of hot and cold plates are considered to be indistinguishable in the project. Although cold plates have a certain work hardening during the cold rolling process, (though the requirements for strict mechanical properties are not ruled out) , Then you need to treat it differently), the cold plate generally has a slightly higher yield strength than the hot plate, and the surface hardness is also higher. The specific degree depends on the degree of cold plate annealing. But no matter how annealed the cold plate is, the strength is higher than the hot plate.

3. Formability. Since the performance of hot and cold plates is not too bad, the factors that affect the formability depend on the difference in surface quality. Since the surface quality is better than that of cold plates, it is usually the same material. The appearance of steel plates and cold plates is better than that of hot plates.

Cold Rolled Steel Sheet is processed and rolled on the basis of hot-rolled steel sheets, and is generally a hot-rolled-pickling-cold rolling process. Cold rolling is a method in which a steel sheet is further thinned to a target thickness below a recrystallization temperature at room temperature. Compared with hot-rolled steel, cold-rolled steel is more accurate in thickness and has a smooth and beautiful surface. Cold-rolled steel plates generally have no heating process before rolling. Cold-rolled hot-rolled steel coils are used as raw materials. After oxidation, cold-rolled rolling with oxidized scale is removed. Performance will deteriorate and can only be used for parts that are simply deformed. In the hot-dip galvanizing device, since the hot-dip galvanizing device is equipped with an annealing line, a hard roll can be used as a raw material.

Cold-rolled steel strip is widely used, such as automobile manufacturing, electrical products, rolling stock, aviation, precision instruments, food cans, etc. Cold rolled steel sheet is short for common carbon structural steel cold rolled steel sheet. It is also called cold rolled steel sheet, commonly known as cold plate. The cold plate is a hot-rolled steel strip of ordinary carbon structural steel, which is further cold-rolled into a steel plate with a thickness of less than 4mm. Because rolling at room temperature does not produce scale, the cold plate has good surface quality and high dimensional accuracy. In addition to annealing treatment, its mechanical properties and process performance are better than those of hot-rolled thin steel plates. In many fields, especially In the field of home appliance manufacturing, it has gradually been used to replace hot rolled sheet steel.

Hot Rolled Steel Sheet

Hot Rolled Steel Sheet can destroy the casting structure of the ingot, refine the grains of the steel, eliminate the structural defects, and thereby improve the microstructure and mechanical properties of the steel. This improvement is mainly reflected in the rolling direction, so that the steel no longer has a certain isotropy, and the bubbles, cracks and pores formed during the casting process can also be welded at high temperature and pressure.

The above is the difference between cold-rolled steel sheet and hot-rolled steel sheet introduced by Galvanized Steel Sheet Manufacturer. Hope to help you.