Abstract: Hot compression deformation behavior of a low-temperature high-Mn steel for welding materials was studied using a Gleeble-3800 thermal simulation testing machine within the temperature range of 800-1000 ℃ and strain rate range of 0.01-10 s^-1. Friction correction and temperature correction were applied to the stress-strain curves. The Arrhenius constitutive equation and the BP neural network constitutive model of the tested steel were established using the corrected flow curves. Additionally, hot processing maps at true strains of 0.2, 0.4, and 0.6 were plotted. The results show that the correlation coefficient between the predicted and tested values of the flow stress in the Arrhenius constitutive model is 0.976. The constitutive model based on the BP neural network has a higher prediction accuracy for the flow stress, with a correlation coefficient of 0.996. The optimal hot processing zone for the tested low-temperature high-Mn steel is as follows: the deformation temperature ranges from 930 ℃ to 1000 ℃, and the strain rate ranges from 0.01 s^-1 to 0.1 s^-1. Combined with the microstructure analysis, it is found that under the process parameters of a deformation temperature of 950 ℃ and a strain rate of 0.01 s^-1, complete dynamic recrystallization can occur in the tested steel, resulting in a uniform and fine equiaxed grain structure.

Key words: low-temperature high-Mn steel, stress correction, constitutive equation, hot processing map, hot deformation behavior