HIGH-STRENGTH GALVANIZED STEEL SHEET HAVING SUPERIOR BENDABILITY AND METHOD FOR PRODUCING SAME

摘要

This high-strength galvanized steel sheet has a maximum tensile strength of at least 900 MPa and results from forming an alloyed galvanizing layer on the surface of a parent material steel sheet containing C, Si, Mn, P, S, Al, N, and O at predetermined quantities, the remainder comprising iron and unavoidable impurities. In the structure of the parent material steel sheet, residual austenite is limited to no greater than 8% by volume fraction; the kurtosis (K*) of the hardness distribution between the 2% hardness and the 98% hardness is no greater than 0.30; the ratio of the Vickers hardness of the surface layer of the parent material steel sheet and the Vickers hardness at 1/4 the thickness of the parent material steel sheet is 0.35-0.70, and the amount of iron contained in the alloyed galvanizing layer is 8-12% by mass%.