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SURFACE TREATING COMPOSITION FOR PLATED STEEL MEMBER HAVING EXCELLENT CORROSION RESISTANCE AFTER HEATING AND ENVIRONMENTAL SUITABILITY, METHOD FOR PRODUCING PLATED STEEL MEMBER, AND PLATED STEEL MEMBER
SURFACE TREATING COMPOSITION FOR PLATED STEEL MEMBER HAVING EXCELLENT CORROSION RESISTANCE AFTER HEATING AND ENVIRONMENTAL SUITABILITY, METHOD FOR PRODUCING PLATED STEEL MEMBER, AND PLATED STEEL MEMBER
PROBLEM TO BE SOLVED: To provide a plated steel member at a low cost, which can widely be applied to use for house appliances/building materials/automobiles or the like, has excellent corrosion resistance after heating and has no elution of hexavalent chromium being an environmental load substance at all.;SOLUTION: In the method for producing a plated steel member having excellent corrosion resistance after heating and environmental suitability, a composition comprising partially reduced chromic acid, a phosphoric compound and a nitric compound as essential components, and having the relations in the following inequalities (I) to (III) among the reduction ratio of chromium (X) in the partially reduced chromic acid and the concentration in a bath of each component is applied to a plated steel member, and drying is performed: inequality (I) is 85(%)≤X; inequality (II) is Y≤1.9 provided that Y=(HNO3/CrO3)+(H3PO4/CrO3); and inequality (III) is Y≥4.5-X/25.;COPYRIGHT: (C)2004,JPO
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