Rolling

In metalworking, rolling is a metal-forming process in which stock is passed through one or more pairs of rolls to reduce its thickness, make that thickness uniform, or impart a desired mechanical property, in much the same way dough is rolled flat. It is classified by the temperature of the metal being worked: hot rolling takes place above the recrystallization temperature of the metal and cold rolling below it, and by tonnage, hot rolling processes more material than any other manufacturing process while cold rolling processes more than any other cold-working process. Roll stands holding pairs of rolls are grouped together into rolling mills that can process metal, typically steel, quickly into products such as structural shapes, bar stock and rails, and most steel mills maintain a rolling mill division that converts semifinished cast products into these finished forms. Variants of the process include ring rolling, roll bending, roll forming, profile rolling and controlled rolling.