Hot deformation behavior and process parameter optimization of 9310 gear steel

The hot deformation behavior of 9310 gear steel is investigated by hot compression test within temperature range from 800 ℃ to 1100 ℃ and strain rate range from 0.001 s⁻¹ to 10 s⁻¹. The peak stress constitutive relation model and processing maps under different strains are constructed and the process parameters are optimized. The results show that the flow stress of 9310 gear steel increases obviously with the decrease of deformation temperature and the increase of strain rate. Under the condition of high temperature (900-1100 ℃) and low strain rate (0.001-0.1 s⁻¹), the flow stress curve primarily exhibits strain softening characteristics. The constitutive relation model demonstrates high predictive accuracy, with a correlation coefficient of approximately 0.998 and an average absolute relative error of about 4.724%. The obtained better deformation process parameters range from 1010 ℃ to 1100 ℃ and from 0.05 s⁻¹ to 1.41 s⁻¹, among which the optimal process parameters are in the range of deformation temperature 1070 ℃ and strain rate 0.05-1 s⁻¹, corresponding to the main plastic deformation mechanism of dynamic recrystallization. The range of unstable deformation process parameters is approximately 800-925 ℃ and 0.04-10 s⁻¹, where flow localization is the primary plastic deformation mechanism. The microstructure verification results are in good agreement with the prediction and optimization results of the processing map.