Influence of Nb, V and Ti on peak strain of deformed austenite in Mo-based micro-alloyed steels

In this paper, the influence of Nb, V and Ti on the peak strain of deformed austenite in Mo-based micro-alloyed steels has been studied. Four steels, identified as Mo, Mo+V, Mo+Nb and Mo+Ti, respectively, were heated to 1200 °C and held for 10 min and then the temperature was rapidly reduced to test temperatures and maintained for 40 s. The test temperatures were 950, 1000, 1050, 1100, 1150 and 1200 °C at the strain rates of 0.05, 0.1, 0.5, 1 and 5 s−1, respectively. Results indicate that the presence of Nb, Ti, and V affects significantly the value of peak strain (εp), especially Nb which has a significant effect on the start of the dynamic recrystallisation. For all the steels studied, the peak strain εp was modelled as a function of the Zener–Hollomon parameter and the austenite grain size.