Research On The Influence Of Grain Size On Cutting Characteristics And Surface Integrity

In the metal cutting process,when the cutting depth approximates to the grain size,material microstructure is considered as a major factor affecting the machining precision and surface integrity.Therefore,it is necessary to study the effect of the grain size on the cutting characteristics and machining quality.In this paper,Three different grain sizes of T2 pure copper workpieces of 45?m,145?m and 360?m were prepared by rolling and heat treatment at different annealing temperatures.The face turning experiment was carried out to study the effect of grain size on cutting characteristics and surface integrity.Based on Deform-3D simulation software,a finite element prediction model for face turning was established.The main research contents are as follows:(1)Through the method of cold-rolling and high temperature heat treatment,pure copper workpieces with different grain sizes which would be used for face turning experiments were prepared at different rolling ratios,heat treatment temperature and holding time.(2)The cutting force signal and pure copper chips were collected during the face turning experiment.Based on the influence of grain size on the material flow stress,the cutting force,chip shape and shear angle of pure copper workpieces with different grain sizes were compared and analyzed to study the effect of grain size on cutting characteristics.(3)By comparing and analyzing the cutting residual stress,plastic flow layer and surface hardening degree of the machined surface of different grain size workpieces,the effect of grain size on the surface integrity of pure copper workpiece was studied based on stress loading cycle and work hardening.(4)A grain size-dependent Johnson-Cook constitutive model was established.The Deform-3D finite element simulation software was used to simulate the face turning process.The effects of grain size on cutting force,surface residual stress and surface plastic deformation were verified by comparing the simulation results with the experimental results.