| 摘要 |
PROBLEM TO BE SOLVED: To provide a method calable of stably producing a thinly coated galvanized steel sheet with a high productivity. SOLUTION: A steel sheet contg., by weight, 0.01 to 0.2% C. <=0.10% Si, 0.08 to 2.5% Mn, 0.025 to 0.1% P, 0.001 to 0.02% S and 0.005 to 0.1% Sol.Al is annealed in a continuous galvanizing line and is thereafter cooled to an impregnating sheet temp. shown in the inequality (3). This steel sheet cooled to the impregnating sheet temp. is immersed into a zinc bath contg. Al in the range shown in the inequality (2), and the coating weight of zinc is controlled. The zinc bath temp. T C is set in the range of the inequality (1) from the relation with the content of Al in the bath, and the initial alloy layer formed on the surface of the steel sheet in the zinc bath is regulated into fineζphases: 335+930×Al<=T<=375+930×Al... (1), Al<=0.20... (2), and 420<=T... (3), where T: the zinc bath temp. ( deg.C) and Al: the content (wt.%) of Al in the bath.
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