| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high strength hot-dip galvanized steel sheet having a tensile strength of 590 MPa or more, which is excellent in the workability (the formability of extension flange) in drilling by laser machining; and to provide a method for manufacturing the same. <P>SOLUTION: The component composition of the high strength hot-dip galvanized steel sheet excellent in the workability includes, by mass%, 0.03-0.15% C, less than 0.5% Si, 1.0-2.5% Mn, 0.05% or less P, 0.01% or less S, 0.05% or less Al, 0.0050% or less N, 0.05-0.8% Cr, and 0.01-0.1% V, and the balance being Fe and inevitable impurities, wherein a microstructure of the steel has ferrite having a mean particle size of 15 μm or less and martensite having an area rate of 5-40%, and in the martensite, the martensite having an aspect ratio of less than 3.0 accounts for more than 95% by area rate of the all martensite. The steel sheet has a galvanized coating film on a surface thereof. <P>COPYRIGHT: (C)2012,JPO&INPIT |
