| 摘要 |
PURPOSE:To produce the title steel sheet having a uniform appearance and excellent corrosion resistance and coating property by coating a chromate soln., obtained by mixing chromic acid at a specified reduction degree, a colloidal compd., and an inorg. anion in a specified ratio, on the surface of a plated steel sheet, and heating, drying, then water washing, and drying the coating. CONSTITUTION:The chromate soln. contg. chromic acid having 0.1-0.7 ratio of Cr<3+>/(Cr<3+>+Cr<6+>), 0.5-3.0 parts colloidal compd. (e.g., silica sol), based on the chromic acid, and 0.02-2 parts inorg. anion (e.g., phosphoric ion) is coated on the surface of a plated steel sheet (e.g., galvanized steel sheet), heated and dried then water washed, and dried. As a result, the chromated plated steel sheet having a uniform appearance and excellent corrosion resistance and coating property can be produced.
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