Effect of Titanium on Hot Deformation Behaviors of Boron Microalloyed Steel

Abstract

The hot deformation behaviors of titanium-free and titanium-treated boron microalloyed steel were investigated at the temperatures from 850°C to 1100°C and strain rates from 0.1 s⁻¹ to 10 s⁻¹ on Gleeble-2000 thermo-mechanical simulator. It was found that the flow stress of the titanium-treated steel is lower than that of titanium-free at lower strain rates, indicating that titanium addition generates a softening effect. The flow stress constitutive equations of hot deformation were developed for the experimental steels, the activation energy of titanium-treated steel (299.7 kJ·mol⁻¹) is higher than that of the titanium-free steel (286.9 kJ·mol⁻¹). Additionally, it is interesting to note that the peak and critical strain are lowered by titanium addition, indicating that titanium has the ability to promote the onset of dynamic recrystallization. However, the dynamic recrystallization kinetics of titanium-free steel is faster than that of titanium-treated steel.