Experimental Researches Of Cylindrical Grinding On Surface Integrity Of 18CrNiMo7-6

With the continuous advancement of"Made in China 2025",domestic universities and research institutions have been deepening their research on surface integrity.Grinding as the final machining process for most parts greatly affects the surface quality of the part and in turn affects its service life.Controlling the surface integrity of grinding not only provides technical support for aerospace,defense,military,transportation and other industries,but also plays an important role in improving the processing quality and life of mechanical products.18CrNiMo7-6 alloy steel has good mechanical properties and processing properties,and has been widely used in the gear industry.In order to better utilize the advantages of 18CrNiMo7-6 alloy steel,control the surface integrity after grinding and improve the fatigue resistance,this paper analyzes the influence of process parameters on surface integrity by cylindrical grinding 18CrNiMo7-6 test.The optimization of the external grinding process parameters provides a test basis.The main research contents are as follows:(1)A single factor test scheme for cylindrical grinding of alloy steel18CrNiMo7-6 was designed,and the surface roughness,three-dimensional surface topography,microhardness and residual stress were respectively determined by three-dimensional shape measurement system,residual stress tester and micro hardness tester.(2)The influence of the parameters of the external grinding process on the surface roughness and three-dimensional surface topography of the workpiece was studied.The optimal process parameters were obtained with the surface roughness as the main consideration.(3)The influence of the parameters of the external grinding process on the microhardness of the workpiece was studied.The results show that The microhardness gradient distribution under different grinding process parameters shows a trend of decreasing first and then keeping stable.Combined with the hardness gradient distribution of the original sample,the grinding process formed a hardened layer of about 30-60?m on the surface layer of the workpiece,and the microhardness was significantly improved relative to the original sample.(4)The influence of the parameters of the external grinding process on the residual stress of the workpiece is studied and analyzed.The results show that The residual stress on the surface of the workpiece under different grinding process parameters is residual compressive stress.Under the different grinding wheel speeds and workpiece speeds,the circumferential residual stress?_x and the axial residual stress?_y in the depth direction are residual compressive stresses,and the peak values are all on the surface,the residual compressive stress value gradually decreases with depth and tends to be stable.At the same time,combined with the residual stress gradient distribution of the original sample,it can be seen that the external cylindrical grinding enhances the residual compressive stress of the surface layer of the workpiece,and a residual stress influenced layer of about 30?m is formed.(5)Grinding simulation was carried out with a single abrasive grain and the residual stress gradient distribution was extracted.The results were compared with the test results to verify the feasibility of single abrasive grinding simulation.