Characterization of hot deformation behavior of a new microalloyed C-Mn-Al high-strength steel

摘要

The compressive deformation behaviors of a new 0.23C-1.50Mn-1.79Al (wt%) based microalloyed high-strength steel were investigated at the temperatures from 900 ℃ to 1100 ℃ and strain rates from 0.01 s~(-1) to 30 s~(-1) on a Gleeble-1500 thermo-simulation machine. The flow stress constitutive equation of hot deformation for this steel was developed with the activation energy Q being about 310 kJ/mol. Activation energy analysis showed that high Al addition in this steel seemed not to affect the activation energy much. A regression expression proposed by Medina and Hernandez [24] to predict the Q value of microalloyed steels was found to have a relative error 2.58% for this steel. The dynamic recrystallization (DRX) analysis showed that the DRX behavior of the experimental steel was evidently affected by both the deformation temperature and the strain rate. The dependence of steady-state grain size, the peak strain and the peak stress on Zener-Hollomon parameter of this steel was plotted and found that the values of Zener-Hollomon exponents of this steel was in reasonable agreement with microalloyed steels without high Al addition.