Analysis Of Microcosmic Geometric Property In Pre-stressed Dry Grinding Process

Based on the concept of green manufacturing and anti-fatigue manufacturing,Pre-stressed dry grinding process has the features of lower energy consumption,integration,less environmental pollution and green processing.The surface micro-geometrical property is one of the important surface integrity indexes,and the numerical and distribution characteristics have a significant effect on the performance of mechanical workpieces.So the study of surface roughness,waviness and other micro-geometric variation tendency and mechanism in pre-stress dry grinding process has become a hot spot,and it is of great significance.In this paper,pre-stress dry grinding test was carried out,and the main contents of this paper are as follows:(1)The grinding mechanism of pre-stressed dry grinding was studied,and the forming mechanism of the workpiece surface in the pre-stress dry grinding process was analyzed.The influence mechanism of macroscopic and microcosmic factors on surface topography was analyzed emphatically,and the effects of microstructure,grinding temperature and pre-stress stress on the microcosmic geometrical properties of the surface were analyzed.(2)The surface morphologie of the grinding wheel was simulated.Based on Johnson system,the surface morphologies of non-Gaussian distributed grinding wheel were simulated.Combined with the effect of prestressing and grinding depth on the grinding wheel and workpiece interference mode and grinding particle coordinate transformation process,the non-Gaussian grinding wheel was obtained with appropriate parameters.The microcosmic geometrical appearance of the workpieces surface was simulated by MATLAB software,and the change of the surface topography and the variation trend of the surface roughness were obtained under different prestressing and grinding depth.(3)Control the grinding depth and the prestressing strength,the pre-stress dry grinding test to 40Cr,45 steel two kinds of workpieces were carried on separately,measure the metallographic structure of the test specimen after the analysis.The microstructure of the workpieces after the test were measured and analyzed.It is concluded that the microstructure of the two workpieces is obviously stratified.And the part near the surface of the workpiece is composed of martensite and ferrite.The depth of the hardened layer of 40Cr is smaller than that of the 45 steel,and the grains of the hardened layer are finer and the structure is more compact and uniform.On the basis of theoretical research,the temperature field of two kinds of workpieces in pre-stress dry grinding were simulated by ANSYS software.And the distribution of the temperature field was obtained.The microstructures of the surface and the contact zone temperature were analyzed to provide the theoretical basis for the hardening strengthening of the workpieces surface.(4)The surface roughness and surface topography of the two workpieces after grinding were measured and compared.The surface roughness of the two workpieces is not uniform.With the increase of the depth of grinding,the surface roughness of the workpieces increase.With the increase of the prestress,the surface roughness of the workpieces decrease,and the test results are in accordance with the simulation results of the surface topography.