Effect of Vanadium and Strain Rate on Hot Ductility of Low-Carbon Microalloyed Steels

Hot tensile tests were conducted in this study to investigate the effect of strain rate (10(-3) and 10 s(-1)) and vanadium content (0.029 and 0.047 wt.%) on the hot ductility of low-carbon microalloyed steels. The results indicate that a hot ductility trough appears at a low strain rate (10(-3) s(-1)) because of the sufficient time for ferrite transformation and the growth of second particles, but it disappears at a high strain rate (10 s(-1)). The hot ductility is improved with the increase in strain rate at 700 degrees C or higher temperatures. In addition, with the increase in vanadium content, the large amounts of precipitate and increased ferrite transformation result in poor hot ductility of steels fractured at a low temperature range (600~900 degrees C). However, when the steel is fractured at a high temperature range (1000~1200 degrees C), more vanadium in the solid solution in the austenite inhibits the growth of parental austenite grains and results in grain refinement strengthening, slightly improving the hot ductility.

Automated summary

This study investigated the effect of strain rate and vanadium content on the hot ductility of low-carbon microalloyed steels through hot tensile tests. The results show that low strain rate leads to poor hot ductility, while high strain rate improves it. Increased vanadium content results in decreased hot ductility at low temperatures, but slightly improves it at high temperatures.