| 摘要 |
A high-strength hot-dip galvanized steel sheet containing a main component, the steel sheet having at least 40 wt. % of ferrite as a main phase in terms of the volumetric ratio, and 8-60% inclusive of residual austenite, the remaining structure comprising one or more of bainite, martensite, or pearlite. Austenite particles within a range where the average residual stress (sigmaR) thereof satisfies the expression −400 MPa<=sigmaR<=200 MPa (formula (1)) are present in an amount of 50% or more in the hot-dip galvanized steel sheet. The surface of the steel sheet has a hot-dip galvanized layer containing less than 7 wt. % of Fe, the remainder comprising Zn, Al and inevitable impurities. |
| 主权项 |
1. A hot-dip galvanized steel sheet, which is a steel sheet comprising, in mass %,
C: from 0.10 to 0.4%, Si: from 0.01 to 0.5%, Mn: from 1.0 to 3.0%, O: 0.006% or less, P: 0.04% or less, S: 0.01% or less, Al: from 0.1 to 3.0%, N: 0.01% or less, and Si+Al≧0.5%, with the balance being Fe and unavoidable impurities, wherein the steel sheet is a high-strength hot-dip galvanized steel sheet comprising, as the main phase, in terms of volume fraction, 40% or more of ferrite and from 8 to 60% of retained austenite, and the balance structure is composed of any one member or two or more members of bainite, martensite and pearlite, wherein out of the austenite, an austenite grain having an average residual stress σR satisfying formula (1) accounts for 50% or more:
−400MPa≦σR≦200MPa (1) and wherein the steel sheet has, on the surface thereof, a hot-dip galvanized layer comprising Fe in an amount of less than 7 mass %, with the balance being Zn, Al and unavoidable impurities. |
