Hot rolled products like hot rolled steel bars are used in the welding and construction trades to make railroad tracks and I-beams, for example. Hot rolled steel is used in situations where precise shapes and tolerances are not required.
Cold Rolled Steel
When referring to bar products, the term used is “cold finishing”, which usually consists of cold drawing and/or turning, grinding and polishing. This process results in higher yield points and has four main advantages:
Cold drawing increases the yield and tensile strengths, often eliminating further costly thermal treatments.
Turning gets rid of surface imperfections.
Grinding narrows the original size tolerance range.
Polishing improves surface finish.
All cold products provide a superior surface finish, and are superior in tolerance, concentricity, and straightness when compared to hot rolled.
Cold finished bars are typically harder to work with than hot rolled due to the increased carbon content. However, this cannot be said about cold rolled sheet and hot rolled sheet. With these two products, the cold rolled product has low carbon content and it is typically annealed, making it softer than hot rolled sheet.