Microstructures and Mechanical Properties of Nb-Ti Bearing Hot-rolled TRIP Steels

Nb-Ti hot-rolled TRIP-assisted steel with high plasticity and appropriate volume percentage of retained austenite based on fine ferrite grain have been developed in the experiment. The test results showed that niobium tend to exist in solution state in matrix with less precipitation, and niobium-titanium could be precipitated in form of (Nb, Ti)C or (Nb, Ti) (C, N), which play an important role in increasing yield strength (from 495 MPa to 610 MPa). Besides, the retained austenite had a positive effect on improving the plasticity by transformation into martensite during tensile deformation.