High Temperature Plastic Deformation Behavior of As-Cast 300M Steel Based on Friction Correction

Abstract

Hot deformation behavior of as-cast 300M steel was investigated in the temperature range of 850-1200°C and strain rate range of 0.01-10 s-1 using Gleeble-3800 thermo-mechanical simulator. Based on the true stress-strain curves corrected for friction, flow stress behavior and deformation mechanism were analyzed, and the constitutive model of as-cast 300M steel was established based on the Arrhenius model and Zener-Hollomon parameter (Z). The microstructure after deformation was observed by Olympus GX51 microscope. The experimental results show that the flow stress of as-cast 300M steel decrease with the increase of deformation temperature and the decline of strain rate. The dynamic recrystallization is more likely to occur at higher temperatures and lower strain rates. By regression analysis, the hot deformation activation energy (Q) of the as-cast 300M steel was calculated to be 360.332 kJ/mol. Microstructure evolution is greatly affected by deformation temperature and strain rate. The dynamic recrystallized grain size increases with the enhancement of deformation temperature and the decrease of strain rate.