Hot rolled steel plates and cold-rolled steel plates are two common types of steel products, which have significant differences in multiple aspects. The following is a detailed comparison of these two types of steel plates:

1、 Production process

Hot rolled steel plate: Produced at high temperatures (usually above 1000 degrees Celsius), steel ingots or continuous casting billets are rolled into relatively thin steel plates by a rolling mill. During the hot rolling process, sulfides, oxides, etc. inside the steel will be compressed into thin sheets. The termination temperature of hot rolling is generally 800~900 ℃, and then it is usually cooled in air, so the hot rolling state is equivalent to normalizing treatment.

Cold rolled steel plate: produced at room temperature, usually using hot-rolled steel coils as raw materials, after acid washing to remove oxide skin, and then cold rolling, further thinning to the target thickness. Due to work hardening during the cold rolling process, cold-rolled steel plates usually require annealing, acid washing, and surface leveling before being handed over to customers.

2、 Appearance and surface quality

Hot rolled steel plate: The surface is relatively rough and may have defects such as oxide scale. It has a variety of colors, including some brown. When the steel plate is thick, it can only be hot-rolled, and hot-rolled steel plates may be affected by thermal expansion and contraction during processing, resulting in changes in thickness and edge width.

Cold rolled steel plate: The surface is relatively smooth, free of defects such as oxide scale, mostly silver in color, and the surface quality (such as surface roughness) is usually better than hot-rolled steel plate. Cold rolled steel plates have a more precise thickness and can achieve very thin specifications.

3、 Mechanical performance

Hot rolled steel plate: has high strength and toughness, but relatively poor plasticity. Hot rolled steel plates have good stamping and welding properties, making them suitable for applications that require significant loads and pressures.

Cold rolled steel plate: It has good plasticity, relatively low strength and toughness, but higher strength and hardness. Cold rolled steel plates have a certain degree of work hardening and low toughness, but can achieve a good yield to strength ratio, making them suitable for applications that require high dimensional accuracy and surface smoothness.

4、 Purpose:

Hot rolled steel plate: commonly used in heavy-duty structures, pressure vessels, steel structural components, bridges, ships, vehicles, and other fields. In addition, hot-rolled steel plates with added special elements such as P, Cu, C, etc. also have good corrosion resistance and atmospheric corrosion resistance, and can be used for the production of containers and special vehicles.

Cold rolled steel plate: It is suitable for fields such as automobiles, home appliances, and construction, especially for components that require high surface smoothness and dimensional accuracy. Cold rolled steel plates can also be used as stamping plates for manufacturing various complex shaped parts.