| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a high strength and high ductility hot-dip galvanized steel sheet which has strength and ductility required as the steel sheet for automobile and exhibits excellent workability in the case of applying a friction-stir welding process etc., and further, is excellent in plating adhesion property. <P>SOLUTION: This steel sheet has a composition composed of 0.05-0.40% C,≤1.5% Si, 0.5-3.0% Mn,≤0.4% Al and satisfying (Si+Al)≥0.5% and the balance Fe with inevitable impurities, wherein a secondary phase containing retained austenite of≥5% volume ratio in a main phase of pro-eutectoid ferrite is formed and further, the sum of a temperature range width of the ferrite single phase and the temperature range width of two-phases of the austenite phase and the ferrite phase, in an equilibrium state of≥600°C, is made≥200°C. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
