Direct and indirect decomposition of retained austenite in continuously cooled bainitic steels: Influence of vanadium

Abstract Direct and indirect decomposition of retained austenite during tempering are investigated in a 0.2C wt% steel with a carbide-free bainitic microstructure. The decomposition products of both mechanisms are quantified using X-ray diffraction and quantitative metallography; using dilatometry data to support interpretation. Two nearly identical steels are compared, with and without vanadium. The influence of vanadium on both direct and indirect decomposition of retained austenite is discussed, along with the effect of vanadium on hardness changes during tempering.