Study On High Temperature Deformation Behavior Of Si2Cr2Mn2MoVNb High Strength Steel

With the rapid development and maturity of today's social science and technology,high strength steels have been used not only in areas such as aerospace,submarines,and various military equipment that have special requirements for material properties,but also in vehicles,rails,minerals,Construction and machinery manufacturing have also gained application.Si2Cr2Mn2MoVNb steel is a newly developed high strength steel with good mechanical properties and broad application prospects.However,the formulation and optimization of the hot-forming process for this high-strength steel is still not perfect.Therefore,the high temperature deformation behavior of this high strength steel needs to be studied,so as to provide experimental and theoretical basis for the formulation and optimization of process parameters.In this project,the thermodynamic behavior and dynamic recrystallization behavior of Si2Cr2Mn2MoVNb high strength steel under different deformation conditions are analyzed in detail with the help of Gleeble-3500 thermal simulation test machine.Based on the experimental data,the true stress-strain curve of the high strength steel is drawn,and the flow stress under different deformation conditions is analyzed.Based on this,a constitutive model is established.A dynamic recrystallization model is constructed,and the influence of deformation parameters on the microstructure is analyzed.Finally,based on the basic principle of the dynamic material model,a hot working drawing of Si2Cr2Mn2MoVNb high strength steel is constructed,and the microstructure of the typical area identified by the hot working drawing was analyzed after thermal deformation.The following main conclusions is reached:?1?When the strain rate is constant,the higher the deformation temperature,the lower the flow stress,and the more pronounced the dynamic recrystallization characteristic;when the strain temperature is constant,the larger the strain rate,the higher the flow stress,and the more obvious the dynamic recovery characteristic.?2?The higher the deformation temperature,the easier it is for dynamic recrystallization,the faster the grains grow,and the more severe the coarsening phenomenon,an appropriate increase in the strain rate is conducive to grain refinement.?3?The optimal deformation parameters of Si2Cr2Mn2MoVNb high strength steel are:the strain rate is 0.01?0.05 s^-1,and the deformation temperature is 1050?1120?.