Carbon Enrichment of Austenite during Ferrite-bainite Transformation in Low-alloy-steel

The bainitic transformation kinetics and carbon enrichment of austenite during isothermal holding at 723–923 K were investigated for an Fe-0.1mass%C-0.5mass%Si-2.0mass%Mn alloy. progressed rapidly until approximately 50 s, after which stasis was observed 823 K. concentration increased as the proceeded, showed almost constant value stasis. It reached 0.45-0.50% K, corresponds to T0’ composition with additional strain energy 100 J/mol associated transformation. After stasis, a slight increase in ferrite or fraction observed. also 0.60%, clearly exceeding T0 composition. These results imply that first stage, bainite occurs shows incomplete transformation, following second diffusional proceeds. calculated from due tends decrease temperature increases. This indicates relaxation occurred higher temperatures.