| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a high-strength low-specific gravity steel sheet excellent in ductility. Ž<P>SOLUTION: The method for manufacturing the high-strength low-specific gravity steel sheet excellent in the ductility, the steel sheet having <7.2 specific gravity, ≥440 MPa tensile strength and ≥25% elongation comprises the processes of: heating a steel slab composed, by mass, of 0.001-0.01% C, ≤3.0% Si, 0.01-3.0% Mn, ≤0.02% P, ≤0.01% S, 5.0-10.0% Al, 0.001-0.05% N and the balance Fe with inevitable impurities to the temperature of ≥1,100°C; and subjecting the heated steel slab to hot-rolling including at least 1 pass or more of the large rolling-reduction having ≥30% rolling-reduction ratio at the temperature of ≥1,000°C and the finish-rolling temperature of ≥800°C. Ž<P>COPYRIGHT: (C)2010,JPO&INPIT Ž
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