Study of the temperature dependence of the bainitic transformation rate ina multiphase TRIP-assisted steel

A prerequisite to the development of multiphase TRIP-assisted steels is a g ood understanding of the bainitic transformation that takes place during th e related thermo-mechanical processing. In this framework, the present pape r proposes to investigate the formation of bainite when originating from in tercritical austenite in a Si bearing steel. The experimental results sugge st the contribution of a martensitic type mechanism to the transformation p rocess. Yet, the overall bainitic reaction rates are found to strongly depe nd on the holding temperature. This original kinetics is correlated with th e typical microstructure the steel exhibits after the intercritical anneali ng stage. To this extent, the crucial role of the adjacent development of b ainitic ferrite for the observed temperature dependence is discussed. (C) 1 999 Elsevier Science S.A. All rights reserved.