| 摘要 |
PROBLEM TO BE SOLVED: To provide a dual-phase type hot dip galvanized high tensile strength steel plate of a hot rolled substrate excellent in workability and to provide a method for producing the same. SOLUTION: Steel containing, by mass, 0.04 to 0.12% C, <=0.1% Si, 1.0 to 2.0% Mn, <=0.05% P, <=0.005% S, 0.05 to 1.0% Cr, 0.005 to 0.2% V, <=0.1% sol.Al and <=0.01% N is subjected to rough rolling, is thereafter subjected to finish rolling at the Ar3 point or more, is coiled at 700 deg.C or less, is thereafter pickled at need, is applied with hot dip galvanizing in which plating preheating temperature is controlled to Ac1 to Ac3 and is cooled after the plating or after alloying treatment to obtain a dual-phase structure essentially consisting of ferrite+martensite.
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