When ordering from steel suppliers one of the most important things to consider is if you need hot or cold rolled steel sheets. The differences between them comes from the way they are manufactured and processed. As the names suggest, cold rolled steel is cooled and tempered while hot utilizes heat for this process.
Hot Rolled Steel
This process involves rolling the steel sheets at an extremely high temperature, around 1700 degrees Fahrenheit, which is well above steels recrystallization threshold. When steel is heated to this temperature it becomes easier to mold and form into the shape and size needed. This process also allows much larger sheets to be created. Additionally, hot rolled steel tends to be more affordable when compared to cold rolled, due to the shorter time it takes to manufacture and the fact that no reheating is needed. However, one drawback is that as the steel cools it will shrink down, which can make the size and shape more unpredictable than it’s cold counterpart.
Cold Rolled Steel
Cold rolled steel follows a similar manufacturing process as the above, but it also goes through additional processing. Steel is heated, cooled at room temperature, and then tempered. This process allows steel to feature more dimensional accuracy, and a wider array of finishes.
Cold finishing refers to a process that includes additional grinding or polishing. This in turn creates higher yield points and a couple additional benefits:
- The process of cold drawing improves the yield strengths, and eliminating the need for any additional heat treatments.
- Finishing improves the look of surfaces and eliminates imperfections on the surface.
- Narrows the size tolerance rage to the original size.
Cold rolled steel tends to have an improved tolerance, straightness, and concentricity. However, Steel suppliers who specialize in cold rolled steel will be able to further explain the benefits, and if they would be right for your project.
Both cold and hot rolled steel have their uses and benefits. Which one you use will depend on your needs, and the particulars of your project. Contact a steel supplier to find out which is best for your particular project.