| 摘要 |
PROBLEM TO BE SOLVED: To provide a composite structure type high-tensile hot-dip galvanized steel sheet having a high r-value and excellent deep drawability, and to provide its manufacturing method. SOLUTION: In the method for manufacturing the composite structure type high-tensile hot-dip galvanized steel sheet, a slab of steel having a composition which consists of, by mass, 0.01-0.08% C, <=2.0% Si, <=3.0% Mn, <=0.10% P, <=0.02% S, 0.005-0.20% Al, <=0.02% N, 0.01-0.5% V and the balance essentially Fe with inevitable impurities and in which V and C satisfy the relation of 0.5×C/12<=V/51<=3×C/12 is hot-rolled, pickled and cold-rolled and the resultant steel sheet is annealed at a temperature in the region between the Ac1 and the Ac3 transformation point and hot-dip galvanized in a continuous hot-dip galvanizing line.
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