The present contribution focuses on the development of hot-rolled, formable high-strength (TS>1000MPa) bainitic steel for automotive applications, which combine a high strength and an adequate formability. The effect of both alloying elements (C, P, B, Si, Cr, Mo and Nb) and thermo-mechanical processing were studied in detail. The steels have a specific relation between their microstructure, which results from composition and processing conditions, and their mechanical properties. This can be used to obtain fundamentally different properties. As a result bainitic steels offer a great flexibility: by e.g. increasing the coiling temperature it is possible to vary the properties from those of a predominantly bainitic microstructure (high yield strength, high YS/TS ratio) to those of the duplex bainiteaustenite microstructure (high tensile strength, low YS/TS ratio, improved formability).
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