Cold Rolled Steel Vs Hot Rolled Sheet

Cold worked steels are typically harder and stronger than standard hot rolled steels.

Cold rolled steel vs hot rolled sheet.

During the hot rolling process steel is heated to its melting point while being worked changing the composition of the steel to make it more malleable. Hot rolled steel has rounded edges a rough surface texture and no grease on its finish. While hot rolled steel is heated then cooled cold rolled steel is heated and cooled at the room temperature and then rolled after again. Cold rolled has a smooth and shiny finish while hot rolled has a grey and scaly finish.

There are three main visual differences between the two processes. Hot rolled steel is rolled or shaped at a high temperature while cold rolled steel is rolled at room temperature. The steel is processed further in cold reduction mills where the material is cooled at room temperature followed by annealing and or tempers rolling. Once hot rolled steel has cooled it is then re rolled at room temperature to achieve more exact dimensions and better surface qualities.

Cold rolled steel is essentially hot rolled steel that has been through further processing. Cold rolled has sharper corners and more precise dimensions than hot rolled. In comparison a cold rolled steel product with the same chemical composition has a yield strength of 365 mpa. Thus the yield strength of cold rolled steel is higher than that of hot rolled steel.

As an example a hot rolled steel product may have a yield strength of 235 mpa. Hot rolled steel is used in situations where precise shapes and tolerances are not required. Cold rolled steel is essentially hot rolled steel that has had further processing. During cold rolling the steel is annealed or exposed to heat and allowed to cool which improves ductility.

The steel is processed further in cold reduction mills where the material is cooled at the room temperature followed by forming the material by either press braking or cold roll forming to achieve the desired shape. Hot rolled steel sheets are used in fabrication work where aesthetics and quality are not. Alternatively cold rolled steel has sharp edges a very smooth surface texture and an oily or greasy feel to it.