In the metalworking industry, as we know, rolling is a metal forming process, which the metal stock is passed through one or more pairs of rolls to reduce the thickness and to make the thickness uniform. Rolling is divided into two types that are hot rolling and cold rolling according to the different of the temperature when metal rolled. If the temperature is above its recrystallization temperature, then this kind of process is known as hot rolling. If the temperature is below its recrystallization temperature when mental rolled, the process is called cold rolling.
In the aspect of usage, the hot rolling process is more tonnage than any other process, and the cold rolling process is the most tonnage for all cold working processes. Roll stands to make pairs of rolls grouped together into rolling mills that can quickly manufacture metal into products, for example, structural steel, bar stock, and rails, steel pipe and so on. Most steel mills have rolling mill department that the main duty of them is to convert the semi-finished casting products into finished products.
There are so many types of rolling processes, mainly including ring rolling, roll bending, roll forming, profile rolling, and controlled rolling.