Finite-elemene Simulation And Experiment On The Residual Strss When Griding Ultrafine Cemented Carbide

Compared with common homogeneous cemented carbides,ultrafine grained cemented carbides which broad market space and application prospect have higher hardness and strength which has been successfully applied to cutting tools,high precision molds and military products.Grinding processing of diamond grinding wheel is the main processing method to ultrafine grained cemented carbides.Due to the result of thermal and mechanical coupling in the grinding processing,residual stress with cracks and other defects has come into being.In this paper,the experimental and simulation studies on residual stress of ultrafine grained cemented carbides are carried out,hoping that can be used to guide the production practice.In this paper,the grinding residual stress test of ultrafine grained cemented carbide under different grinding parameters is carried out by using high precision surface grinder.In order to get the influence law of residual stress in grinding,factors of abrasive particle size of grinding wheel,grinding depth,workpiece feed speed,grinding wheel speed were analyzed.The experimental results show that the grinding residual stress of ultrafine cemented carbide increases with the grinding depth.With the increase of grinding depth,the grinding force and grinding temperature increase,leading to the increase of the residual stress caused by the coupling of forces and thermal processes,which is the cause of this experimental phenomenon.The residual stress of ultrafine grained cemented carbide increases with the small in rease of workpiece feedrate.the reason is that the action time of the heat source on the surface of the workpiece will be relatively shortened which reducing the effect of grinding heat reduce.The residual stress of grinding decreases with the increase of grinding wheel speed.This is mainly because with the increase of grinding wheel speed,average undeformed chip thickness of single abrasive particles decreases with the chip cross-sectional area decreases,The residual compressive stress produced by extrusion processing effect of a single abrasive particle will decrease.In addition,the finite element simulation software ANSYS is using to analyzethe effects of grinding parameters on grinding residual stress.First,thermal analysis,the results of thermal analysis as a thermal load applied to the force-thermal coupling field a mouvable uniform thermal flux and grinding force distribution were taken into account in the analysis.The workpiece is separated into some sections according to the contact length of the grinding wheel with the suiface.According to the speed of the grinding wheel and the grinding time and section,the calculation process is divided into several steps.The load is moved along the suiface of workpiece.Each step of movemengt is eual to the contace length.and compared with the grinding experiment analysis,the simulation results show that the influence of grinding parameters on grinding residual stresses are close to the experimental results,the simulation and experiment results error is between 3.5% and 10.5%,proved the accuracy of the finite element model.