| 摘要 |
PROBLEM TO BE SOLVED: To provide a process for manufacturing a multiphase high tensile hot-dip galvanized steel sheet with a good appearance of a plating film and an excellent deep-drawability. SOLUTION: In the manufacturing process, after a steel slab is hot-rolled, pickled and cold-rolled, it is subjected to oxidation treatment in a heating zone with an oxidative atmosphere and a dew point controlled to≥20°C, continuously annealed in a reducing atmosphere at 780-950°C and subsequently subjected to hot-dip galvanizing in a continuous hot-dip galvanizing line. The steel slab has a composition comprising, by mass, 0.01-0.05% C, 0.1-1.0% Si, 1.0-3.0% Mn,≤0.10% P,≤0.02% S, 0.005-0.1% Al,≤0.02% N, 0.01-0.2% V and 0.005-0.2% Nb, provided that contents (mass%) of V, Nb and C satisfy the relation: 0.5×C/12≤(V/51+Nb/93)≤2×C/12. COPYRIGHT: (C)2004,JPO
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