Patent ID: 10633720

Abstract:
A high-strength galvanized steel sheet having a chemical composition containing, by mass %, C: 0.07% to 0.25%, Si: 0.01% to 3.00%, Mn: 1.5% to 4.0%, P: 0.100% or less, S: 0.02% or less, Al: 0.01% to 1.50%, N: 0.001% to 0.008%, Ti: 0.003% to 0.200%, B: 0.0003% to 0.0050%, and the balance being Fe and inevitable impurities, in which the relationship Ti>4N is satisfied, and a microstructure including, in terms of area ratio in a cross section located at ¼ of the thickness from the surface of a base steel sheet, a ferrite phase in an amount of 70% or less (including 0%), a bainite phase in an amount of 20% or less (including 0%), a martensite phase in an amount of 25% or more, and a retained austenite phase in an amount of less than 3% (including 0%), in which the average crystal grain diameter of the martensite phase is 20 μm or less, and in which a variation in the Vickers hardness of the martensite phase is 20 or less in terms of standard deviation, as well as a method for manufacturing the steel sheet, is disclosed.