Abstract: The dynamic recrystallization behaviors of Ti micro-alloyed 510L steel for automobile frame were investigated using single-pass compression tests and hot-rolling and quenching tests for step samples. The results show that when the strain rate is 0.1s^-1， the dynamic recrystallization can occur at the deformation temperature ranging from 850 to 1050℃; while， when the strain rate is 0.2s^-1， it only occurs at the temperature above 950℃.With increasing the deformation temperature and strain， the average grain size of the austenite decreases and the volume fraction of recrystallization increases. By regression analysis， the activation energy for dynamic recrystallization in the tested samples is 211.43kJ/mol， which indicates that the addition of Ti has little effect on dynamic recrystallization behavior of the high-temperature austenite. The critical strain and kinetic models for dynamic recrystallization are also established.

Key words: Ti micro-alloyed, frame steel 510L, dynamic recrystallization, activation energy, mathematical model