Simulation And Experimental Research On The Effect Of Shot Peening On The Surface Integrity Of Gear Steel

Gear has the advantages of stable transmission ratio,high carrying capacity,high efficiency,etc.,and it is widely used in the movement and power transmission of aviation,wind power,automobiles,ships and other equipment.However,gear still faces failure problems such as pitting,spalling,and tooth root fracture during service,which restrict the reliability and safety of the high-end equipment.With the rapid development of industry,the requirements for the surface quality,fatigue strength,and reliability of gears are increasing.Gear manufacturing have shifted from traditional "shape control" manufacturing to "shape and performance synergistic" manufacturing.Ways to improve the surface quality of gears include shot peening,surface heat treatment,and finishing.Among them,shot peening has the characteristics of significant strengthening effect,low cost,high efficiency,and environmental protection,and it is widely used in the gear industry.The surface quality of the gear after shot peening is affected by many shot peening parameters,such as shot velocity,shot diameter,shot peening angle,shot peening coverage rate,etc.,resulting in the selection of shot peening parameters depends on experience,and the effect of shot peening is not good.Inappropriate selection of shot peening parameters will damage the surface integrity of the gears and cause a waste of resources.Aiming at the problem of unclear correlation between shot peening parameters and surface integrity,the gas-solid two phase flow shot peening model to study effect of air peening equipment parameters such as air pressure,shot peening distance,and shot flow rate on shot velocity.A random multi-shots shot peening finite element model,which adopts the dislocation-based elastoplastic constitutive equations,was established to analyze the effect of shot velocity,shot diameter,shot peening angle,and double shot peening on the material surface.The shot peening process and surface integrity inspection of gear steel was carried out to clarify the effect of shot peening parameters on surface integrity,providing theoretical basis for shot peening of high-performance gears.The main research contents are as follows:(1)Research on shot velocity based on CFD.Based on the geometric parameter characteristics of the venturi nozzle and the range of the air peening equipment parameters,the gas-solid two-phase flow shot peening model was established.The effects of air peening equipment parameters,such as air pressure,shot flow rate,shot distance on the shot velocity were discussed;(2)Analysis of the influence of shot peening parameters on surface integrity parameters.According to the characteristics of the random distribution of shots in space during the shot peening process,a random multi-shot shot peening finite element model was established,and the elastoplastic constitutive based on dislocations was adopted.The effect of shot velocity,shot diameter,shot angle and double shot peening on material surface morphology,dislocation cell size and residual stress;(3)Gear steel shot peening process and surface integrity inspection.Design the geometric size and processing technic of the specimens according to the geometry and processing technic of large-modulus wind power gears tooth surface.The surface roughness,residual stress,hardness of the test pieces before and after shot peening were tested to investigate the actual effect of shot peening parameters on the material surface integrity.The simulated and experimental results were compared to verify the correctness of the model.