| 摘要 |
PROBLEM TO BE SOLVED: To provide a means for solving the unevenness of the hue in the width direction generated at the time of producing a black color galvanized steel sheet by zinc phosphate treatment. SOLUTION: As to the method for producing a black color galvanized steel sheet, a galvanized steel sheet or a galvannealed steel sheet is degreased, water- washed, thereafter treated with a Ti hydroxide particle-contg. alkalescent surface conditioner soln. and is sprayed with an Ni ion-contg. zinc phosphate treating agent soln. to form a zinc phosphate film having >=2 g/m2 film coating weight, and the hue of the steel sheet is controlled to 45 to 60 lightness index L value. In this case, the concn. of fluoride ions in the zinc phosphate treating agent soln. is controlled to 60 to 200 ppm.
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