Study on theoretical model of roughness and wear of the microgrinding tool in microgrinding nickel-based single crystal superalloy

Abstract

Nickel-based single crystal superalloy has no grain boundary and excellent high-temperature performance. The traditional grinding mechanism of shearing and slipping along the polycrystalline material's grain boundary based on the theory of elastic-plastic deformation is not suitable for grinding single crystal parts. At present, there are few studies on microgrinding nickel-based single crystal superalloy. The grinding quality directly affects the workpiece's service life. To realize highquality and low-damage grinding nickel-based single crystal superalloy (001) crystal plane, this paper studied the surface roughness and the wear of the microgrinding tool. Firstly, it was assumed that the protrusion height of the electroplated abrasives on the grinding tool obeyed Rayleigh distribution. Based on the cutting state of abrasives, the prediction model of surface roughness of microgrinding nickel-based single crystal superalloy was established and verified by experiments. Secondly, the effect of grinding parameters on microgrinding surface roughness was analyzed through a single-factor experiment. Finally, the main wear forms, wear mechanism of grinding tool and the influence of grinding parameters on wear of grinding tool were analyzed. The results showed: although there was some error between the predicted value and the experimental value, the predicted value of the roughness and the experimental value had the same trend with the change of microgrinding parameters; with the increase in spindle speed (n g ) and the decrease in grinding depth (a p ), the surface roughness of microgrinding nickel-based single crystal superalloy showed a decreasing trend; with the increase in feeding rate (v w ), the surface roughness increased obviously; the wear of the grinding tool could be divided into five forms; the diameter of the microgrinding tool showed a trend of rapid reduction, then steady reduction, and finally rapid reduction under all grinding parameters. This study provided an important theoretical and practical reference for the manufacturing of nickel-based single crystal superalloy microparts.