| 摘要 |
PROBLEM TO BE SOLVED: To provide a high tensile strength hot dip plated steel sheet which hardly causes the generation of unplated part even though it is a high tensile strength steel sheet. SOLUTION: A high tensile strength steel sheet having a composition, as steel components, containing, by mass, Si of 0.5 to 1.5%, and one or more kinds of 0.03 to 1.5% in total selected from 0.005 to 0.2% Nb, <0.5% Cu, <1.0% Ni and <1.0% Mo combinedly added thereto after controlling Si and Mn so as to satisfy a relation of 5×Si (mass%)<Mn (mass%), is subjected to recrystallization annealing at >=750 deg.C in a reducing atmosphere having dew point of <=0 deg.C to >=-45 deg.C and is thereafter cooled. Next, oxides formed on the surface of the steel sheet are pickled and removed, and again, the steel sheet is heated at 650 deg.C to 850 deg.C in a reducing atmosphere having dew point of <=-20 deg.C. In the process of temperature reduction from the above reheating temperature, hot dip plating treatment is performed to the steel sheet.
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