| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot pressing method for a steel sheet by which high strength after high temperature forming can be obtained. SOLUTION: The hot pressing method for a steel sheet is characterized in that a ferrite+austenite dual phase structure in which the ferrite phase is present in an amount of 5 to 30% by area ratio is obtained by heating a steel sheet comprising 0.15 to 0.35% C and 1.5 to 3.5% Al, and the balance Fe with inevitable impurities at 850 to 1,050°C, and is subjected to press forming with a die heated at≤150°C, and thus a formed part is obtained which has, as a microstructure, a ferrite+martensite dual structure in which the ferrite phase is present in an amount of 5 to 30%, and the ratio of the Al concentration in the ferrite phase to the Al concentration in the martensite phase is≥1.5. COPYRIGHT: (C)2006,JPO&NCIPI
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