Patent ID: 8828557
Filing Date: 2014-09-09
Classification: B32B,C21D,C22C,C23C,Y10T

Abstract:
1. A high strength galvanized steel sheet having excellent formability, weldability, and fatigue properties, comprising: a composition of C: 0.05% to <0.12%, Si: 0.35% to <0.80%, Mn: 2.0 to 3.5%, P: 0.001 to 0.040%, S: 0.0001 to 0.0050%, Al: 0.005 to 0.1%, N: 0.0001 to 0.0060%, Cr: 0.01% to 0.41%, Ti: 0.010 to 0.080%, Nb: 0.010 to 0.080%, B: 0.0001 to 0.0030%, Ni: <0.04% and Mo: <0.05% all in mass %, and Fe and an unavoidable impurity as the balance; a microstructure comprising a recrystallized ferrite phase with a volume fraction of 20 to 70% and an average grain diameter equal to or smaller than 5 μm; a tensile strength equal to or higher than 980 MPa; an endurance ratio of 0.42 or more; and a galvanized layer on a surface thereof at a coating weight (per side): 20 to 150 g/m 2 .