HIGH-STRENGTH GALVANIZED STEEL SHEET EXCELLENT IN BENDABILITY AND MANUFACTURING METHOD THEREOF

摘要

The present invention provides a high-strength galvanized steel sheet with maximum tensile strength of 900 MPa or more. The high-strength galvanized steel sheet has an alloyed galvanized layer formed on a surface of a base steel sheet containing predetermined amounts of C, Si, Mn, P, S, Al, N, 0 with a balance being constituted of iron and inevitable impurities, in which in a structure of the base steel sheet, retained austenite is limited to 8% or less in volume fraction, kurtosis K* of the hardness distribution between 2% hardness and 98% hardness is -0.30 or less, a ratio between Vickers hardness of surface layer of the base steel sheet and Vickers hardness of 1/4 thickness of the base steel sheet is 0.35 to 0.70, and a content of iron in the alloyed galvanized layer is 8 to 12% in mass%.