What is the difference between cold-rolled coil and hot-rolled coil?

Hot-rolled coil and cold-rolled coil refer to different steel processing processes, which are different in process and product performance. The following Shanghai cold rolled coil manufacturer will briefly introduce the difference between hot rolled coil and cold rolled coil.

1. Technology

Hot rolled coils are made by heating billets to slightly above the grain boundary temperature at high temperatures and then rolling into coils under high pressure. Therefore, Shanghai hot rolled coil manufacturers believe that the processing temperature of hot rolled coil is much higher than that of cold rolled coil, usually above 1000 degrees. The cold-rolled coil is to cool the billet and form it at room temperature. Therefore, its processing temperature is much lower than the hot coil, and it is generally carried out at room temperature.

2. Mechanical properties

Because of the low processing temperature of the cold-rolled coil, the grain size is fine and uniform, so its strength, hardness and plasticity are better than that of the hot-rolled coil. Cold-rolled coils are not only stronger, but also easier to deep draw and bend. On the contrary, the grain of the hot-rolled plate will be deformed due to overheating, resulting in poor strength and poor finish.

3. Surface quality

Due to the high temperature of hot rolled coil processing, the surface is easy to produce rust and oxidation layer, and the surface of the hot rolled plate is uneven and a little pockmarked. As a result, the surface quality of hot rolled coils is poor and not suitable for applications requiring high surface states. Cold rolled coil processing process because of low temperature, processing speed, in the surface quality performance is better, more flat, smooth.

4. Application

Hot rolled plate is mainly used in steel structure plant, large machine manufacturing and container and other pressure equipment. The compactness of cold-rolled sheet is good, so it is widely used in stamping, home appliances and electrical appliance manufacturing in the automotive industry. Because of the fine surface of the cold-rolled coil, it can be used in higher application requirements, and is widely used in occasions requiring surface requirements, such as home appliances, kitchenware, building materials, decorations and so on.

In short, there are differences in the processes and application fields of hot-rolled coils and cold-rolled coils. Compared with hot-rolled coil, cold-rolled coil can better meet the needs during construction, so it is widely used.