Experiment And Analysis Of Physical Properties Of Bearing Ring Surface Based On Nitrogen Jet Hard Turning

Bearing is widely used in all walks of life,and its performance is directly related to the service life of the whole equipment.With the development of modern industry and science and technology,the high reliability,high precision,bearing capacity,dynamic performance,high speed and high temperature and light quantization,miniaturization and combination are put forward more and more high requirements,which have higher requirements for the quality of each bearing assembly.As an important part of the bearing,the surface quality of the bearing ring directly affects the life and efficiency of the bearing.Bearing rings are hardened materials.In recent years,turning grinding instead of grinding as the last working procedure of finish machining of hardened materials has been put forward and applied.However,when turning high hardness Gcr15,a lot of heat will be generated.The higher cutting temperature will directly affect the surface quality and machining efficiency of the workpiece.In order to explore the way to improve the surface quality of hard turning parts,the effect of nitrogen cooling environment on the surface quality of hardened parts was studied.In this paper,the simulation model of nitrogen cooling and dry cutting is established by the finite element simulation method,and the temperature distribution of the workpiece in the two cutting environment is solved.Taking the tip of a knife node as an example,the curve of temperature changing with time is output,and the cutting time needed for temperature stabilization is obtained.Moreover,the stable temperature values near the cutting edge 1mm and the temperature values of several nodes in the 1mm of the workpiece surface are output.It provides simulation basis for subsequent temperature measurement and surface residual stress distribution.According to the relationship between the node temperature and the temperature field in the simulation results,a temperature measurement scheme based on the tool temperature and temperature simulation is designed.The cutting experiment was designed and the temperature measurement method was used to compare the cooling effect of nitrogen cooling to dry cutting and the influence of three cutting factors on the cutting temperature.Furthermore,the effect of cutting three elements on the roughness and hardness of the bearing rings under two environments was studied in the dry nitrogen cooling environment.The difference of roughness and hardness of workpiece after cutting with the same parameter and the change rule of the variation with the cutting factor are compared.Based on the experimental results,we explored the best combination of processing parameters for obtaining high surface quality.Finally,the cutting parameters are selected according to the experimental results and the residual stress in the surface surface of the two cutting environment is collected to obtain the effect of nitrogen cooling on the residual stress on the surface of the workpiece.