PRODUCTION OF HOT-DIP COATED STEEL SHEET

PURPOSE:To produce the hot-dip coated steel sheet excellent in corrosion resistance and chemical convertibility with high productivity by subjecting cold rolled steel sheet to degreasing treatment, prescribed oxidation, reduction annealing, electric arc treatment, and thereafter hot dipping treatment. CONSTITUTION:A hot rolled steel sheet by low carbon aluminum-killed steel and dead soft steel, dead soft alloy steel, etc., is subjected to deoxidizing treatment and scale on the surface is eliminated, and thereafter, rust preventing oil is applied and cold rolling is executed. After oil such as the rust preventing oil, rolling oil, etc., on the surface of this cold rolled steel sheet 1 is removed, it is subjected to oxidizing/annealing or reducing/annealing. Subsequently, the cold rolled steel sheet is supplied into a vacuum chamber 4, the steel sheet 1 is set as the cathode and an electric arc 7 is generated between the cathode and the anode 6, an injurious contaminant containing a metallic oxide on the surface of the steel sheet is completely removed, and thereafter, hot dipping with molten Zn, etc., is performed. In such a way, the molten metal plating steel sheet excellent in corrosion resistance and chemical convertibility can easily be produced.