Effect of deformation in the intercritical area on the grain refinement of retained austenite of 0.4C trip steel

Abstract

Producing steels with higher strength without loss of formability has been the subject of many recent investigations. The combination of high strength and high formability of steels can be achieved using the concept of Transformation Induced Plasticity (TRIP). Developing TRIP steels along the hot rolling route has not been studied extensively. This route opens an opportunity for improving the properties of TRIP steel by deformation in the intercritical area. No study about the influences of deformation in the intercritical area has been made systematically. Such deformation in the intercritical area has a substantial effect on microstructures and mechanical properties of TRIP steel. It increases dislocation density, refines retained austenite grain and enriches the carbon content of retained austenite. All of those properties significantly improve the stability of retained austenite, which on its turn enhances the strength and work hardening behavior of the steel. The present study shows that deformation in the intercritical area influences the size and the morphology of the different phases -- ferrite, bainite and retained austenite -- of the resulting microstructure.