| 摘要 |
PROBLEM TO BE SOLVED: To provide a plated steel sheet excellent in adhesiveness using directly electric plating equipment by executing cathodic electrolytic pickling of a hot- rolled steel sheet having a scale of iron oxide of a specific thickness in a pickling tank in the electric plating equipment to remove the scale and continuously executing the electric plating successively after being washed with water. SOLUTION: A hot-rolled steel sheet having a scale consisting of iron oxide of 0.1-5μm thickness per one side, is drawn, preferably to impart a stain by repeated bending, etc., and to provide the scale with cracks of 1-1000 pieces/mm and then, the electrolytic pickling is executed in a pickling tank in electric plating equipment with a steel sheet as a cathode. The electrolytic pickling uses a solution containing 10-300 g/l sulfuric acid and is preferably executed under the condition of 40-80 deg.C in temperature, 50-500 A/dm<2> in current density and 300-3,000 C/dm<2> in quantity of electricity. Alternatively, the cracks of 10-1,000 pieces/mm are provided in the scale and the hot-rolled steel may be pickled with a solution containing 50-500 g/l hydrochloric acid at a temp. of 50-80 deg.C for 2-10 seconds. The descaled steel sheet is washed with water and then, successively continuously, electric-plated.
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