1) Cold-rolled sheets are produced via a cold-rolling process; their surfaces are free of mill scale, resulting in high quality. Hot-rolled sheets, conversely, are produced via a hot-rolling process; their surfaces retain mill scale, and their thickness typically exhibits a negative tolerance (i.e., is slightly thinner than nominal).
2) Hot-rolled sheets generally exhibit poorer toughness and surface flatness, and are lower in price; cold-rolled sheets, on the other hand, possess excellent ductility and toughness, though they come at a higher cost.
3) Rolling processes are broadly classified into cold rolling and hot rolling, with the material's recrystallization temperature serving as the distinguishing criterion.
4) Cold Rolling: Cold rolling is typically employed in the production of steel strips and is characterized by relatively high rolling speeds. Hot-Rolled Sheets: The temperatures involved in hot rolling are comparable to those used in forging operations.
5) In their unplated state, hot-rolled steel sheets present a dark brown surface finish, whereas unplated cold-rolled sheets appear gray. Once plated, the two types can be distinguished by their surface smoothness, as cold-rolled sheets possess a significantly smoother finish than hot-rolled steel sheets.