Effects of austempering on the mechanical properties of the hot rolled Si−Mn TRIP steels

Abstract

The effect of austempering on the mechanical properties of the hot rolled Si−Mn TRIP steels was studied. The mechanism of transformation induced plasticity (TRIP) was discussed through the examination of the microstructure and the mechanical properties of the specimens. The results show that the microstructures of the steels were comprised of polygonal ferrite, granular bainite and a significant amount of stable retained austenite. The specimen exhibits excellent mechanical properties for the TRIP effect. Isothermal holding time for austempering affects the stability of retained austenite. The mechanical properties such as tensile strength, total elongation and strength ductility balance reach their optimal values (776MPa, 33% and 25608 MPa%, respectively) when the specimen is held at 400°C for 25 min.