| 摘要 |
This high-strength hot-dip galvanized steel sheet has a component composition comprising, in mass%, C: 0.15%-0.25%, Si: 0.50%-2.5%, Mn 2.3%-4.0%, P: 0.100% or less, S: 0.02% or less, and Al: 0.01%-2.5%, and further comprising at least one element of Nb: 0.005%-0.1%, Ti: 0.005%-0.1%, V: 0.01%-1.0% and Mo: 0.005%-2.0%, the remainder being Fe and unavoidable impurities, and has a steel sheet structure comprising, by area ratio, a tempered martensite phase: 30%-73%, a ferrite phase: 25%-68%, a residual austenite phase: 2%-15%, and other phases: 10% or less (including 0%), said other phases including a martensite phase: 3% or less (including 0%) and a bainitic ferrite phase: less than 5% (including 0%), wherein the average crystal grain diameter of the aforementioned tempered martensite phase is 8μm or less, the average crystal grain diameter of the aforementioned ferrite phase is 5μm or less and the amount of C in the aforementioned residual austenite phase is less than 0.7 mass%. A production method of this high-strength hot-dip galvanized steel sheet is also provided. |
