PURPOSE: To obtain a steel sheet for a can having superior corrosion resistance and weldability by forming an iron plating layer on the surface of a steel sheet and successively depositing prescribed amts. of metallic Cr and chromium oxide on the plating layer.
CONSTITUTION: A steel sheet as the cathode is immersed in a known plating soln. contg. Fe2+ and electric current is applied to form an iron plating layer on the surface of the steel sheet by reduction plating. This plating layer is plated with 30-150mg/m2 metallic Cr by cathodic treatment in a usual bath contg. CrO3 as a base and sulfuric acid as a catalyst. The steel sheet is then washed and 3-30mg/m2 chromium oxide is deposited by electrolysis in a bath contg. CrO3 as a base and sodium silicofluoride as a catalyst. A steel sheet having superior corrosion resistance and weldability is obtd.
KOYAMA KENJI
YOSHIDA MITSUO
ITO KAZUHITO
