Hot Deformation Behavior and Hot Working Diagram of 817 Gun Steel
The work aims to study the heat distortion behaviour of 817 gun steel,optimize the process parameters and obtain the best heat distortion interval.The hot compression test of 817 gun steel was carried out by Gleeble hot compression simula-tion machine at 850-1 150 ℃ and strain rates of 0.01-10 s-1.The thermal deformation rheological stress curves of different pa-rameter intervals were plotted through the experimental data points.And the high-temperature rheological ontological model with coupled strain variables was established by combining with the traditional thermal deformation ontological model.The dy-namic material model(DMM)and Prasad plastic instability criterion were used to calculate the energy dissipation factor and in-stability factor of the gun steel to obtain the thermal working diagram of 817 gun steel.Results showed that the flow stress curve of 817 gun steel exhibited typical dynamic recrystallization characteristics,and the plastic deformation stress of 817 gun steel decreased with the increase of deformation temperature and the decrease of strain rate.The correlation coefficient between the predicted value and the experimental value reached 0.991 2,reflecting that the model could describe the theological behavior of 817 gun steel during hot working.After establishing the thermal processing map,it is found that the 817 gun steel may be desta-bilized at low deformation temperatures and high strain rates,and the recrystallization features are found to be obvious through the metallographic organization within the high energy dissipation region.The recrystallization behavior occurs at high tem-perature and low strain rate.The optimum thermal deformation interval of 817 gun steel is finally concluded as follows:tem-peratures of 1 000-1 100 ℃ and strain rates of 0.01-0.14 s-1.
817 gun steelheat compressionrheological behaviorconstitutive modelhot working diagram
万方数据
维普
