| 摘要 |
A multi-phase steel sheet having microstructure having in combination ferrite, martensite of between 3% and 65% by volume, and at least one microstructure selected from the group consisting of, bainite and retained austenite, and having fine complex precipitates selected from the group of TiC, NbC, TiN, NbN, (Ti.Nb)C, (Ti.Nb)N, and (Ti.Nb)(C.N) particles having at least 50% smaller than 20 nm in size, and physical properties having tensile strength greater than about 780 megapascals and at least one of the properties of elongation greater than about 10%, yield ratio greater than about 70%, and hole expansion ratio greater than about 50%.
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