980 HIGH-STRENGTH HOT-DIPPED GALVANIZED STEEL SHEET AND HIGH-STRENGTH ALLOYED HOT-DIPPED GALVANIZED STEEL SHEET EACH HAVING TENSILE STRENGTH OF 980MPA OR MORE EXCELLENT PLATING ADHESION EXCELLENT FORMABILITY AND EXCELLENT BORE EXPANDING PROPERTIES AND METHOD FOR PRODUCING SAME

摘要

Wherein the base steel sheet comprises, by mass%, 0.05 to 0.4% of C, 0.01 to 3.0% of Si, 0.1 to 3.0% of Mn, 0.1 to 3.0% of Mn, a molten zinc plated layer of Al : 0.01 to 2.0% Si + Al 0.5%, P: not more than 0.04%, S: not more than 0.05%, N: not more than 0.01%, the balance being iron and inevitable impurities, Wherein the microstructure of the microstructure contains martensite and bainite in a total volume fraction of 40% or more, retained austenite in a volume fraction of 8% or more, and the remaining microstructure has a volume fraction of ferrite or ferrite Wherein the martensite contains at least 10% of at least two kinds of martensite (1), (2), and (3) in a total volume fraction, and the molten zinc- A plating adhesion with a tensile strength of 980 MPa or more containing Fe in an amount of less than 7 mass% And hole expandability having excellent high-strength hot-dip galvanized steel sheet.