Simulation And Experimental Study Of 20CrMnTi Shot Peening And Development Of Analysis Software

20CrMnTi is the common material of transmission gear in transmission system,so it is of great significance to study how to improve its fatigue life.Shot peening technology can effectively improve the fatigue strength of parts,which is a very common surface treatment technology.In order to study the strengthening effect of shot peening process on 20CrMnTi material,a single shot model and a multi-shot random distribution model were established to study the influence of various process parameters on the strengthening effect.After that,experiments were carried out to verify the accuracy of finite element simulation.At the same time using Matlab software combined with ANSYS software to develop the shot peening simulation software.The fatigue test was carried out to study the influence of different shot peening parameters on the fatigue life of 20CrMnTi material.On this basis,the second shot peening test was carried out to analyze the effect of the second shot peening with different prefatigue cycles.The research contents of this paper include the following aspects:(1)Finite element simulation of single shot model.The effects of different projectile diameters,velocities and angles on the residual stress and surface roughness of the target plate were studied by using the control variable method.By comparing and analyzing the residual stress and surface roughness generated by the projectile impacting the target plate under different parameters,the optimal process parameters for the material studied in this paper are obtained.(2)Finite element simulation of multi-shot random distribution model.Set the projectile randomly generated in space,control other parameters unchanged,set a different number of projectiles hit the target plate,to simulate the coverage rate on the impact of shot peening effect.The residual stress and surface roughness generated by different coverage rates were compared to observe the surface morphology of the target plate under different coverage rates.The results show that when the coverage rate is more than 100%,the reasonable selection of coverage rate can achieve good shot peening effect and save the process cost.(3)Shot peening simulation software development.The simulation software of shot peening was developed by using GUI module in MATLAB software.The main functions can be realized are:automatic shot peening enhancement simulation,while processing the result data,according to the needs of the user in the shot peening parameter database to match the optimal shot peening process parameter combination,convenient for the user to choose.(4)Experimental study on shot peening.Shot peening test was carried out on 20CrMnTi sample,the residual stress layer and surface roughness of the sample after shot peening were detected,and the effect of different shot peening pressure and different shot peening coverage rate on the sample shot peening was studied.The test results were mutually verified with the simulation results.The effects of shot peening on the microstructure of the material were analyzed by using Olympus BC51M microscope.(5)Fatigue test study.The fatigue life of 20CrMnTi samples was obtained by the fatigue test after different shot peening pressure and coverage rate,and the effects of shot peening pressure and coverage rate on the fatigue life of the materials were studied.The second shot peening was carried out under different number of pre-fatigue cycles,and the effect of the number of pre-fatigue cycles on the second shot peening was studied.