| 摘要 |
A high-strength hot-dip zinc coated steel sheet which has a TS value of 590MPa or above and excellent workability; and a process for the production thereof. The composition contains by mass C: 0.05 to 0.3%, Si: 0.7 to 2.7%, Mn: 0.5 to 2.8%, P: 0.1% or less, S: 0.01% or less, Al: 0.1% or less, and N: 0.008% or less with the balance consisting of Fe and unavoidable impurities. The structure comprises, in terms of area fraction, 30 to 90% of ferrite phase, 3 to 30% of bainite phase, and 5 to 40% of martensite phase, and at least 30% of the martensite phase has aspect ratios of 3 or above. It is preferable that the structure contain at least 2% of retained austenite phase in terms of volume fraction and the mean grain diameter of the retained austenite be 2.0μm or below. |
