| 摘要 |
PROBLEM TO BE SOLVED: To provide a high-strength steel sheet having excellent rigidity in which tensile strength is≥590 MPa, a Young's modulus in the 90°direction to the rolling direction is≥230 GPa, and the average Young's modulus in the 0°, 45°and 90°directions to the rolling direction is≥210 GPa, and to provide its production method. SOLUTION: The high-strength steel sheet having excellent rigidity has a composition comprising, by mass, 0.02 to 0.15% C,≤0.3% Si, 1.0 to 2.5% Mn,≤0.05% P,≤0.01% S,≤1.0% Al,≤0.01% N, 0.01 to 0.2% Ti and 0.1 to 0.4% Mo, and in which the contents of C, N, S, Ti and Mo satisfy equations (1) and (2), and the balance Fe with inevitable impurities, and has a microstructure comprising a ferrite phase of≥90% by area ratio, and in which the average ODF (Orientation Distribution Function) analysis strength (f) in the (113)[1-10] to (223)[1-10] orientation of the sheet face in the 1/4 sheet thickness of the steel sheet is≥10, where the equations (1) to (2) are: Ti<SB>-1</SB>/Mo=0.4 to 0.6 ...(1), and C-(12/47.9)×Ti<SB>-1</SB>-(12/95.9)×Mo<0.010 ...(2), wherein, Ti<SB>-1</SB>=Ti-(47.9/14)×N-(47.9/32.1)×S, and each atomic symbol in the equations denotes the content of each element. COPYRIGHT: (C)2007,JPO&INPIT
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