| 摘要 |
Tin free steel having three layers consisting of a bottom layer of metallic chromium, a middle layer of metallic nickel and a top layer of hydrated chromium oxide on a steel base, and a method for the continuous production of this tin free steel which comprises; (a) chromium plating a steel base to form a layer of metallic chromium and hydrated chromium oxide; (b) nickel plating the chromium plated steel base by using a nickel plating electrolyte sufficiently acidic to dissolve the hydrated chromium oxide and (c) forming a hydrated chromium oxide layer on the chromium plated nickel plated steel base. Instead of step (b) in the above method, a cathodic treatment in an acidic solution can be carried out for the removal of the hydrated chromium oxide formed during chromium plating, and thereafter nickel plating can be carried out. This tin free steel is useful for producing welded can bodies at high speed without removing the plated layer in the welded part, since it has an excellent weldability. |
