Using Gleeble-3800 thermal simulation machine, the hot compression experiment was conducted to investigate the deformation mechanism and microstructure evolution of Fe-18Cr-9Mn-1.1Ni-1.1Mo-0.2N duplex stainless steel (DSS) in the temperature of 1 123-1 423 K, and the strain rate of 0.01-10 s-1. According to the hyperbolic sine equation, the peak flow stress constitutive equation of the Z parameter was established after determining the value of stress level constant α, meanwhile, the thermal processing drawings under different strain have been drawn. In the dynamic recrystallization (DRX) region of low deformation strain rate 0.01-0.1 s-1and high deformation temperature 1 323-1 423 K, the smaller value of strain corresponding to the peak stress, the easier occurring of austenite DRX. At the same strain rate, the auste-nite phases change from dynamic recovery to DRX with the increase of deformation temperature. The ferrite DRX mainly occurred in the middle deformation temperature region of 1 123-1 223 K. The deformation apparent activation energy Q was calculated as 578.46 kJ/mol based on thermal deformation equation, which is higher than that of 2205 DSS (451 kJ/mol), and the apparent stress exponent n was calculated as 8.439 8, indicated that the deformation mechanism is structure stability model based on lattice self-diffusion controlled. The analysis of hot processing maps shows that the instable regions gradually increase with the increase of strain on the condition of high strain rates. The optimized thermal processing area was determined to be in the strain rate of 0.01-0.08 s-1, in the deformation temperature of 1 323-1 423 K, and the corresponding high values of power dissipation coefficients are between 0.30-0.52, thus, the austenite DRX occurred under this deformation conditions for tested steels. © 2019, Materials Review Magazine. All right reserved.
