Numerical And Experimental Study On Residual Stress And Surface Topography Of 9310 Steel Spiral Bevel Gear Generated By Shot Peening

Shot peening process is a key process of high surface integrity manufacturing of spiral bevel gears.It improves the anti-fatigue performance of gears.The key point of the research is to predict the shot peening effect,so as to choose the process parameters reasonably.In order to improve efficiency of the industrial production,plan the parameters with low cost and realize the controllable manufacturing of shot peening process,it is necessary to establish the numerical model of spiral bevel gear shot peening process,and study the correlation law between process parameters and strengthening effect.Therefore,this paper takes the spiral bevel gear made of 9310 steel as the research object,and carries out the following studies:(1)The mechanical response of 9310 steel with three levels of hardness were studied by quasi-static tensile/compressive experiments and split Hopkinson tension/pressure bar tests.A constitutive equation considering hardness was proposed based on Johnson-Cook constitutive model,and the tensile/compressive constitutive equation parameters were obtained to characterize the stress-strain relationship of the material in the numerical model.(2)Based on the principle of elastic-plastic mechanics and law of conservation of energy,the expanding cavity model of single shot impacting target plate is established.Combined with the improved Johnson-Cook constitutive equation,the residual stress distribution after impact was obtained.The error between the calculated results and simulated results is within 20%,which can the two methods verify each other,and provide theoretical basis for the establishment of simulation model.(3)Single factor experiments of spiral bevel gears with different types of shots were carried out.The residual stress distribution and surface roughness were measured and compared.The results show that under the impact of ASH110 high hardness shot,the gear teeth can obtain the optimal residual stress gradient and surface roughness.The surface residual stress is 832.18 MPa,the maximum residual compressive stress value can reach1174.06 MPa,and the maximum residual compressive stress layer depth is24 μm.The Sa values of convex and concave roughness are 0.3468 μm and0.3265 μm,respectively.(4)By combined the discrete element coupled method and finite element model,the shot peening numerical model for 9310 steel spiral bevel gear are established,which can take the shot impact between each other and initial surface integrity parameters into consideration.Compared with experimental results,the results show that the simulation model which adopts the compression constitutive equation has higher prediction accuracy,and the errors are within 10%.(5)Based on the numerical model of shot peening process we have established,the effects of different initial surface states,shot impact number,shot velocity and shot diameter on the surface integrity of the gear were studied.It is found that the parameters of initial integrity and shot peening process parameters all have significant influence on the results.The higher initial roughness will lead to the higher roughness after shot peening.Shot peening mainly affects the residual stress field from the surface to the depth of 60 μm.When the coverage increases from 100% to200%,the surface compressive residual stress and maximum compressive residual stress change little,but the depth of maximum residual stress layer increases.Larger shot diameter and velocity can effectively increase the maximum residual compressive stress and residual stress depth,but also increase the roughness.When the full coverage is reached,the change of shot diameter and velocity works little on the residual compressive stress on the surface of target.In this paper,a method for calculating the shot peening process surface integrity of 9310 steel spiral bevel gear is proposed,which can be used to predict the residual stress and surface roughness of the shot-peened spiral bevel gear in actual machining.Based on this study,the correlation law between shot peening process parameters and the surface integrity after shot peening is obtained,which can guide engineering application.