| 摘要 |
PROBLEM TO BE SOLVED: To improve surface ruggedness characteristic and also to improve the image clarity of coated film by regulating the coating weight and spangle diameter of galvanizing layer of a galvanized steel sheet to be coated, respectively. SOLUTION: The coating weight C(g/m<2> ) of a steel sheet and the spangle diameter D(mm) of a plating layer are regulated so that they satisfy the relation of inequality 50<=C<=-100×D+200, where D in the inequality means the mean value represented by L/n when a straight line of a length of L(mm), drawn in an arbitrary direction on the surface of the plating layer, crosses (n) pieces of spangles. Although it is effective to improve surface smoothness to a greater extent by performing dull skin pass rolling after plating, the area ratio of the dull skin pass reduction region in the average projection drawing of the plating layer is regulated to <=70%, preferably <=50%. Moreover, Pb content and Sb content in the plating layer are regulated to <=0.04% and <=0.05%, respectively.
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