Study on hot deformation behavior of 12%Cr ultra-super-critical rotor steel

The hot deformation behavior of a 12%Cr ultra-super-critical rotor steel was investigated through compression test using Gleeble-3500 thermal–mechanical simulator within the temperature range of 1173–1473 K and the strain rate range of 0.01–10 s−1, and the corresponding flow curves were determined. The results showed that the flow stress and the peak strain increase with the drop in the deformation temperature and the rise in the strain rate. The critical Z value, below which the complete dynamic recrystallization may occur, is 3.53 × 1017. The hot deformation activation energy of the steel is 439 kJ/mol, and the hot deformation equation isε˙=1.773×1015[sinh(ασp)]4.420 exp−439,000RT.For the convenience of the practical application, the regressed peak stress can be described asσp=16.7 ln ε˙+881,802T−507.3.