Hot Deformation Behavior And Forming Simulation Of GH2132 Superalloy

GH2132 superalloy bolts are widely used in the connection of hot end parts of engine.However,problems such as uneven distribution of microstructure and cracks are easy to occur in the process of hot working,so the workability of this kind of alloy under high temperature conditions is greatly limited.In this paper,the thermal deformation behavior of GH2132 superalloy was studied by combining experimental research,theoretical analysis and numerical simulation,and the flow stress constitutive model and thermal working diagram were established.The optimal thermal working interval was determined based on the microstructure,the microstructure evolution law of GH2132 superalloy was studied,and the dynamic recrystallization model of the alloy was established.Based on the finite element method,the hot compression process of GH2132 superalloy and the bolt hot upsetting forming were simulated.The main research results are as follows:（1）Study on thermal deformation constitutive model and thermal working diagram of GH2132 superalloy.The flow behavior of GH2132 superalloy with deformation temperature of 950～1100℃and strain rate of 0.01～5s^-1 was predicted by hot compression experiment.The correlation coefficient was 0.9944 and the average relative error was 4.55%.Based on the dynamic material model,the hot working diagram of the alloy was constructed,and the optimum hot working interval of the alloy was determined to be 1000～1050℃/0.01～0.22s^-1.（2）Study on microstructure evolution and dynamic recrystallization model of alloy during hot compression.The effects of different deformation parameters on grain morphology and dynamic recrystallization of the alloy were investigated by EBSD technology.It is found that the dynamic recrystallization of the alloy is more obvious at high temperature and low strain rate,and the grain boundary orientation changes with different deformation parameters.The dynamic recrystallization model of GH2132superalloy was established,and the hot compression process was simulated by finite element software.The results show that the dynamic recrystallization volume fraction is in good agreement with the experimental results.（3）Numerical simulation of hot upsetting forming of GH2132 superalloy bolts.According to the optimal hot working interval determined by the hot working diagram and microstructure analysis,the finite element simulation was carried out for the hot heading forming of GH2132 superalloy bolts.The influences of different process parameters on the equivalent strain,equivalent stress,damage value,dynamic recrystallization volume fraction and deformation load were analyzed.The reasonable process parameters for hot heading forming were determined as follows:Deformation temperature T=1050℃,deformation velocity V=15mm/s,friction coefficientμ=0.3.