Hot Rolled Steel vs. Cold Rolled Steel: A Basic Comparison

by Lavina Sharma 10 year's Experience in Fashion Designing.

Steel is of extreme importance to the construction industry on many fronts, and its physical properties ensure that it is always in demand when there is something to be built. Different types of steel have to undergo a variety of processes in order to achieve specific physical properties. While most people may understand that cold-rolled steel and hot-rolled steel are different, they may not know the answer to what the differences are in their production, and what applications they serve.

As suggested by the name, both are passed through either two or four rolls that squeeze the steel and apply pressure to shape it. Stainless steel manufacturers in India follow processes that are slightly different for the two kinds of steels. The differences are mentioned below.

In the case of hot rolled steel, the process involves rolling the steel at a temperature that is above the steel’s recrystallization temperature. This takes place above 1700 degrees Fahrenheit. This kind of steel can be shaped and molded much more easily than steel that is colder, and steel can start in larger sizes. It is also most economical to produce than cold rolled steel and can be produced efficiently without delays so that the steel does not need to be reheated. During the cooling period, the hot rolled steel will shrink and its size and shape will be less predictable than those of cold-rolled steel. Hot rolled steel will also have a scaly grey finish and less precise corners than cold-rolled steel. This makes it more suitable for applications where extremely precise measurements are not required.

The mechanical properties of the steel depend more upon its grade or chemical makeup. This is why one should not make assumptions based on the mechanical properties of hot or cold rolled steel unless they are of the same grade.

Cold rolled steel is manufactured at temperatures that are below its recrystallization temperature. This often means around room temperature, and because it is manufactured at a low temperature, there is no need to worry about the steel shrinking, or changing the appearance. Cold finished steel bar has a much smoother appearance, and as opposed to hot rolled steel, it may have square corners and more precise dimensions and an accurate finish. The yield, as

well as tensile strength of cold-rolled steel, would be higher than hot rolled steel, which means that cold rolled steel is less likely to fracture under pressure.

Coming to the applications, cold-rolled steel is preferred in machining, where the quality of steel is crucial in determining the quality of the final product that is produced, and where the appearance of the steel is an important aspect.