Hot rolling is a mill process which involves rolling the steel at a high temperature (usually at a temperature over 1700° F), which is above the steel’s recrystallization temperature. When steel is above the recrystallization temperature, it can be shaped and formed easily, and the steel can be made in much larger sizes. The process involves passing metal sheets, produced from billets, through rollers above the metal’s (steel) recrystallization temperature.