| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a high strength hot dip zinc-coated steel sheet having both of formability and impact resistance, and a manufacturing method therefor. <P>SOLUTION: The hot dip zinc-coated steel sheet contains a composition including, by mass%, C:0.05 to 0.5%, Si:0.01 to 2.5%, Mn:0.5 to 3.5%, P:0.003 to 0.100%, S:0.02% or below, Al: 0.010 to 0.5%, B:0.0002 to 0.005%, Ti: 0.05% or below, while satisfying Ti>4N, and the balance Fe with unavoidable impurities, a tempered martensite having an area ratio of 60 to 95%, and a retained austenite having an area ratio of 5 to 20%, or further ferrite having an area ratio of 10% or below (including 0%) and/or a martensite having an area ratio of 10% or below (including 0%), and has texture in which the tempered martensite has a mean particle size of 5 μm or below. <P>COPYRIGHT: (C)2012,JPO&INPIT |
