One of the main differences between cold rolled steel and hot rolled steel is the way they are processed. Cold rolled steel is processed at room temperature, usually below its recrystallization temperature. It passes through a series of rolls that compress the steel and increase its strength and hardness. On the other hand, hot-rolled steel is processed at high temperatures, usually above its recrystallization temperature. It passes through the rolls at a lower pressure, which results in a less precise and consistent end product.
Another difference between these two types of steel is their mechanical properties. Cold-rolled steel is usually stronger and more durable than hot-rolled steel due to the high pressure and low temperature of the cold rolling process. On the other hand, hot-rolled steel is more malleable and can be easily shaped and formed.
There are also differences in the surface finish of these two types of steel. Cold rolled steel has a smoother and more polished surface finish due to the high pressure and low temperature of the cold rolling process. Hot rolled steel has a rougher and more inconsistent surface finish due to the lower pressures and higher temperatures of the hot rolling process.
In terms of applications, cold rolled steel is generally used in applications where accuracy and consistency are important, such as the manufacture of automotive parts or precision equipment. Hot-rolled steel is more commonly used in applications where malleability and formability are important, such as in the construction industry.