HIGH-STRENGTH AND LOW-DENSITY STEEL SHEET SUPERIOR IN DUCTILITY AND FATIGUE CHARACTERISTIC, AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a high-strength and low-density steel sheet superior in ductility and fatigue characteristics, and to provide a manufacturing method therefor.;SOLUTION: The high-strength and low-density steel sheet superior in ductility and fatigue characteristics comprises, by mass%, 0.001% or more but less than 0.02% C, 0.2-3.0% Si, more than 0.2% but 3.0% or less Mn, 0.02% or less P, 0.01% or less S, 3.0-10.0% Al, 0.001-0.05% N, further as needed, one or more elements of Ti, Nb, Cr, Ni, Mo, Cu, B, V, Ca, Mg, Zr and REM, and the balance Fe with unavoidable impurities; has a specific gravity of less than 7.5; includes ferrite of 95% or more by an area rate; has a tensile strength of 380 MPa or higher, an elongation of 25% or longer and a fatigue strength of 0.6 times or more than tensile strength by a both-sided plane bending test.;COPYRIGHT: (C)2006,JPO&NCIPI