HIGH-STRENGTH HOT DIP ZINC PLATED STEEL SHEET HAVING EXCELLENT MOLDABILITY, AND METHOD FOR PRODUCTION THEREOF

摘要

In steel having a tensile strength of 780 MPa or more, a high-strength galvanized steel sheet having excellent formability and a method for manufacturing the same are provided. In the steel sheet, under conditions in which the addition of Al is suppressed to a level which is used for general deacidification, the product of the tensile strength and the total elongation is 15,000 MPa·% or more, and the product of the tensile strength and the hole expansion rate is 45,000 MPa·% or more. The high-strength galvanized steel sheet having excellent formability contains as a chemical component of steel on a mass percent basis: 0.05% to 0.3% of C; more than 0.60% to 2.0% of Si; 0.50% to 3.50% of Mn; 0.003% to 0.100% of P; 0.010% or less of S; 0.010% to 0.06% of Al; 0.007% or less of N; and the balance including Fe and inevitable impurities, and in the microstructure of the steel sheet, the standard deviation of nano-hardness is 1.50 GPa or less.