The main difference between hot rolled steel and cold rolled steel is the temperature at which they are processed. Hot rolled steel is rolled above the material’s recrystallization temperature, whereas cold rolled steel is rolled below the material’s recrystallization temperature. Beyond this quality, there are a few other distinctions between the two materials, including in regard to the following:

• Surface quality. Hot rolled steel tends to have rough edges and surfaces that require decarburization or other treatments to prepare it for use in subsequent production operations. In contrast, cold rolled steel generally has a shiny and smooth surface that allows it to be used as-is in production operations.
• Material hardness. The cold rolling process produces steel with much higher strength and hardness than the steel produced by the hot rolling process.
• Internal stress. The greater material strength and hardness introduced by the cold rolling process comes with greater internal stresses. These stresses must be relieved before the material can be processed; otherwise, the final part or product may experience warping.

These two steel types should not be confused with the technical specifications or grades used to classify steel by composition or physical characteristics. Steel can be hot rolled or cold rolled regardless of its metallurgical specifications or grade.

When evaluating steel options for a project, it is important to keep in mind that some materials will work better than others for certain purposes. Understanding which type of steel offers the right properties for a given application can prevent overspending on raw materials and save time in the long run.