Study On The Surface Residual Stress Of 40CrNiMoA Alloy Steel In High Speed Cylindrical Grinding

The cage of main shaft bearing of domestic engine is generally made of 40CrNiMoA alloy steel.In order to improve the performance,life and reliability of the main shaft bearing of the engine,it is necessary to reduce the surface residual stress produced in the process of cylindrical grinding of the cage.In view of the above problems,the paper carried out the research on the surface residual stress of 40CrNiMoA high-speed cylindrical grinding.Due to the close relationship between the nature and size of grinding surface residual stress and grinding specific energy,grinding force and grinding temperature,the influence of grinding process parameters on grinding specific energy,grinding force and grinding temperature was studied in this paper.Then the residual stress of grinding surface can be effectively controlled.The finite element simulation model and the BP neural network prediction model of the surface residual stress of 40CrNiMoA alloy steel in high speed cylindrical grinding were established,and the prediction of the surface residual stress in high speed cylindrical grinding of 40CrNiMoA alloy steel is realized.The main research contents of this paper include the following four aspects:(1)The orthogonal experiment of high speed cylindrical grinding of 40CrNiMoA alloy steel was carried out.The linear speed of grinding wheel,rotational speed of workpiece and grinding depth were selected as orthogonal experimental factors.The data of grinding power in grinding process was collected by digital power meter,and the grinding specific energy value was obtained by the empirical formula of grinding specific energy;the tangential grinding force value was obtained by the empirical formula of tangential grinding force;the temperature data of grinding area in grinding process was collected by infrared thermal imager,and the residual stress of workpiece surface after grinding was measured by blind hole dynamometer.(2)The range analysis and variance analysis of grinding specific energy,tangential grinding force,grinding temperature and grinding surface residual stress under different grinding parameters were carried out.The effects of grinding parameters on the grinding specific energy,tangential grinding force,grinding temperature and surface residual stress of 40CrNiMoA alloy steel were obtained,and the corresponding optimization method of grinding parameters was proposed.(3)The polyhedral abrasive model and CBN wheel model were established.The simulation of 40CrNiMoA grinding surface residual stress was carried out based on Abaqus,and the tangential grinding force,grinding temperature and residual stress of grinding surface under different grinding parameters were obtained.The validity of the simulation model was verified by comparing the simulation value of tangential grinding force,grinding temperature and residual stress with the experimental value of surface residual stress.(4)The database system of cylindrical grinding was established.Based on BP neural network,the prediction model of grinding surface residual stress of 40CrNiMoA was established.The validity of the prediction model was verified by comparing the prediction value of grinding specific energy,tangential grinding force,grinding temperature and residual stress with the experimental value.