Study On Recrystallization Behavior Of 38CrMoAl Steel

In this paper,the recrystallization and grain growth behavior of 38 CrMoAl steel during high temperature processing were studied in order to guide the actual production.The mechanical properties and microstructure of 38 CrMoAl Steel were studied by using Gleeble experimental equipment.The main research contents are as follows:The effect of heating temperature and holding time on the grain growth of 38 CrMoAl Steel was studied by heating and holding experiments with Gleeble equipment.It is found that the grain size of 38 CrMoAl Steel tends to grow with the increase of heating temperature or holding time.The metallography of 38 CrMoAl Steel was obtained by metallographic experiment,and the Sellars equation of grain growth of 38 CrMoAl Steel was obtained.The effect of temperature and strain rate on the dynamic recrystallization of 38 CrMoAl Steel was studied by means of single pass hot compression experiment with a thermal simulation equipment.The results show that dynamic recrystallization is more likely to occur when the temperature increases,and the critical strain of dynamic recrystallization is also reduced;with the increase of strain rate,dynamic recrystallization is difficult.According to the single pass compression stress-strain curve of 38 CrMoAl Steel,the rheological stress constitutive equation,dynamic recrystallization critical strain equation,dynamic recrystallization kinetic equation and dynamic recrystallization grain size equation of 38 CrMoAl Steel are established.In addition,the hot working diagram of 38 CrMoAl Steel is established,and the unstable region and ideal working conditions of the steel are determined according to the hot working diagram.Based on the obtained critical strain of dynamic recrystallization of 38 CrMoAl Steel,the double pass compression experiments of metadynamic and static recrystallization were completed,and the influence of different process parameters on the metadynamic and static recrystallization behavior of the steel was studied.It is found that with the increase of deformation temperature,the metadynamic and static recrystallization of 38 CrMoAl Steel is faster,but the grain size after recrystallization is larger.The larger the strain rate is,the faster the metadynamic and static recrystallization is,and the smaller the recrystallization grain size is.Compared with the deformation temperature and strain rate,the initial grain size and prestrain have little influence on the metadynamic recrystallization rate,but have some influence on the metadynamic recrystallization grain size.The larger the initial grain size is,the larger the recrystallization grain size is,and the larger the prestrain is,the smaller the recrystallization grain size is.For static recrystallization,the larger the initial grain size,the smaller the recrystallization rate and the larger the recrystallized grain size.The larger the pre strain,the higher the static recrystallization rate and the smaller the recrystallization grain size.In addition,the metadynamic and static recrystallization kinetic equations and grain size equations of 38 CrMoAl Steel were established.