Numerical Simulation And Process Optimization Of Radial-axial Ring Rolling For 42CrMo Steel

At present,the numerical simulation of the whole process of ring rolling mainly focuses on the ring rolling part.How to coupling the influence of the blank making process on the microstructure evolution of the ring rolling process into the finite element simulation of the whole process of ring rolling,and then optimizing the parameters of the blank making and rolling process reasonably has great significance for improving the forming quality of the ring rolling.In this thesis,according to the whole process of 42 Cr Mo steel wind turbine ring radial-axial rolling,the constitutive equation was established through the hot-compression experiment and coupled to the finite element simulation software.On this basis,the finite element simulation model of the whole process of ring radial-axial rolling was established to study the influence of different initial conditions on the process of ring billet.The response surface method was used to simulate the forming process and optimize the forming process of the ring billet making process and the ring square rolling process,and finally analyzed and studied the macro and micro simulation results and changes of the ring in the whole rolling process,and obtain the following main research results:(1)Based on the hot compression experiment at 900-1200 ℃,0.01-10 s-1 and true strain of 0.51,the constitutive equation of hot deformation of 42 Cr Mo steel for ring parts is established:(2)After the billet making processes such as upsetting,blanking blind holes and blanking skin,besides preparing the billet for the subsequent ring rolling stage,the initial grain size can also be refined through effective plastic deformation and dynamic recrystallization,and the difference in ring performance caused by the difference in initial grain size can be reduced to a certain extent.(3)For billets with different initial grain sizes,the grain refinement effect in the billet making process becomes more significant with the increase of grain size.The degree of grain refinement in different regions is related to the degree of deformation.The larger the deformation,the higher the proportion of dynamic recrystallization,the more significant the grain refinement.(4)For billets with different initial temperatures,the grain size of billets section is close in the upsetting and blanking processes,and the initial temperature has little effect on the grain size.The grain size of billet section grows to a certain extent during the blanking skin stage.(5)Response surface method was used to optimize the process of green ring parts,and the optimal parameters were as follows: the upsetting amount was 682 mm,the pressing speed of upper die was 16.40 mm/s and the initial grain size was 75 μm.(6)Response surface method was used to optimize ring square rolling process parameters by multi-objective and multi-parameter.The optimal square rolling process parameters were obtained as follows: drive roll speed was 3.22 rad/s,the amount of radial feed was 111.50 mm and the amount of axial feed was 31.83 mm.