HIGH STRENGTH STEEL SHEET HAVING MAXIMUM TENSILE STRENGTH OF 1300 MPa OR MORE AND EXCELLENT IN MOLDABILITY, HIGH STRENGTH GALVANIZED STEEL SHEET, HIGH STRENGTH ALLOY GALVANIZED STEEL SHEET AND MANUFACTURING METHOD THEREFOR

摘要

PROBLEM TO BE SOLVED: To provide a high strength steel sheet having a maximum tensile strength of 1300 MPa or more and excellent in moldability, a high strength galvanized steel sheet and high strength alloy galvanized steel sheet.;SOLUTION: There is provided a high strength steel sheet having a component composition containing, by mass%, C:0.1 to 0.6%, Si:1.0 to 3.0%, Mn:1.00 to 5.20%, P:0.04% or less, S:0.05% or less, Al:0.001 to 2.0%, N:0.01% or less, O:0.01% or less, and the balance iron with inevitable impurities and a micro structure containing, by volume percentage, tempered martensite of 20 to 90%, bainite of 5 to 75%, austenite of 5 to 25% and ferrite of limited 10% or less, having a maximum tensile strength of 1300 MPa or more and excellent in moldability.;COPYRIGHT: (C)2015,JPO&INPIT