| 摘要 |
PROBLEM TO BE SOLVED: To provide a hot rolled steel sheet for an automobile which has excellent impact resisting strength at a high strain rate, and is easily subjected to press forming. SOLUTION: The hot rolled steel sheet has a componential composition comprising, by weight, 0.05 to 0.20% C, 0.01 to 1.50% Si, 0.5 to 3.0% Mn, and≤0.010% S, also comprising one or more kinds of metals selected from 0.03 to 0.15% P, 0.5 to 2.0% Cr, and 0.1 to 1.0% Mo, and further comprising one or two kinds of metals selected from 0.03 to 1.0% Ti and 0.01 to 0.2% Nb, and the balance Fe with inevitable impurities, and has a two phase structure consisting of martensite having a mean particle diameter of≤3μm and ferrite having a mean particle diameter of≤5μm, and in which the volume ratio of the martensite is 5 to 30%. COPYRIGHT: (C)2004,JPO
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