Tin-plate consists of sheets of steel, coated with a thin layer of tin. Before the advent of cheap milled steel the backing metal was iron. While once more widely used, the primary use of tinplate now is the manufacture of tin cans.
Tin-plate is made by rolling the steel (or formerly iron) in a rolling mill, removing any mill scale by pickling it in acid and then coating it with a thin layer of tin. Plates were once produced individually (or in small groups) in what became known as a pack mill. In the late 1920s pack mills began to be replaced by strip mills which produced larger quantities more economically. Formerly, tinplate was used for cheap pots, pans and other holloware. This kind of holloware was also known as tinware and the people who made it were tinplate workers.
For many purposes, tinplate has been replaced by galvanised (zinc-coated) vessels, though not for cooking as zinc is poisonous. The zinc layer prevents the iron from rusting through sacrificial protection with the zinc oxidizing instead of the iron, whereas tin will only protect the iron if the tin-surface remains unbroken.