Composition and method for weldable tin-free steel having a chromium bilayer

摘要

A method for producing a tin free steel having double layers consisting of a lower layer of flatly deposited metallic chromium and an upper layer of insoluble hydrated chromium oxide which is characterized by a dissolution of soluble hydrated chromium oxide after the formation of three layers consisting of a bottom layer of metallic chromium, a middle layer of insoluble hydrated chromium oxide and an upper layer of soluble hydrated chromium oxide on a steel base by using a chromic acid electrolyte with a small amount of fluoride compound. By using this tin free steel, a welded can body can be produced at high speed without the removal of the plated layer in the welded part because this tin free steel has an excellent weldability.