Influence of Cooling Rate on Transformation Behavior of 0.15% V Microalloyed Steel

Dilation study was carried out in a thermo-mechanical simulator to understand the phase transformation behavior of a 0.15% vanadium microalloyed steel at three different cooling rates, i.e., 2, 5, and 10 °C/s. Results of the study showed that the phase transformation temperatures, namely Ar3, Ar1, and Bs of 0.15% vanadium microalloyed steel increased with increase in the cooling rate from 2 to 10 °C/s. It was also observed that a cooling rate of 5 °C/s was sufficient to form bainite microstructure in the plates while both bainite and martensite were formed when cooling rate was increased to 10 °C/s. The findings of dilation study were used to design a rolling programme for commercial production of high strength steel plates of 0.15% vanadium steel chemistry.