| 摘要 |
PURPOSE:To improve the rust resistance of a steel sheet and the suitability to chemical conversion treatment as well as to remove contaminants and oxide films from the surfaces of the steel sheet and to make the appearance fine by electrocleaning the steel sheet in an aqueous soln. contg. an oxycarboxylic acid and a salt thereof. CONSTITUTION:An annealed cold rolled steel sheet having contaminants stuck and oxide films formed during manufacture is immersed in an electrolytic soln. of 2-7pH contg. an oxycarboxylic acid such as citric acid or tartaric acid and a salt thereof such as the Na salt, and the steel sheet is alternately electrolyzed as the anode and cathode. At this time, a stainless steel sheet is used as a counter electrode. The contaminants and oxide films are removed from the surfaces of the steel sheet to clean the surfaces, and the rust resistance of the steel sheet and the suitability to chemical conversion treatment such as phosphating are improved.
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