Effect of Nb content on microstructures and properties of TRIP steels

The hot deformation process of low silicon TRIP steels with different Nb content was simulated by Gleebe-1500 hot mechanical simulator.The effects of niobium content on microstructures and properties of TRIP steel were studied.The results showed that microstructures of experimental steels were refined and bainite content was increased with the addition of Nb.If Nb content was added,retained austenite fraction and carbon contents of retained austenite decreased,and Vickers hardness and tensile strength increased.When Nb content was 0.014(mass,%),retained austenite fraction was 19.2%,carbon contents of retained austenite was 1.422%,Vickers hardness was 258HV and tensile strength was 851MPa,respectively.