Austenite Formation in Si-Mn TRIP Steels

摘要

As is well established, the occurrence of transformation induced plasticity phenomenon in Si-Mn bainitic TRIP steels increases the strength without scarificing the ductility. In the application of TRIP properties, presence of retained austenite with the desired stability is essential and this in turn is dicated by the steel microstructure. In view of the fat that heat treatment is the most accepted implement to induce the suitable microstructure in steel, an understanding of the austenitization steps is necessitated. Accordingly, in the present study the effects of austenitizing temeprature and time on the formation of austenite in Si-Mn TRIP steels have been investigated. The related Avrami's parameters for different heat treating conditions have also been extracted. The results indicated that the mechanism of austenite formation is strongly affected by the compositions (i.e. C, Si, Mn and Nb) of the steels.