| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable 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, 0.005 to 0.15% 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. T deg.C is immersed into a zinc bath contg. Al in the range shown in the inequality (2), and the coating weight of zinc is regulated. The impregnating sheet temp. T deg.C into the zinc bath 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 350<=T...(3), where T: the impregnating sheet temp. ( deg.C) and Al: the content (wt.%) of Al in the bath.
|
