Study on force and temperature characteristics of micro-grinding nickel-based single-crystal superalloy

Abstract

Aiming at the status of fewer researches on the anisotropy of single-crystal superalloy and micro-grinding temperature field, micro-grinding using the tool of < 1 mm in diameter to remove material is the final procedure of machining micro-parts. This paper firstly analyzes the anisotropy of surface-centered cubic structural material and establishes the theoretical model of elastic modulus and shearing modulus of single-crystal superalloy in the (001), (110) and (111) crystal plane. Afterward, it builds the three-dimensional simulation model of grinding temperature based on the Hill model, adopts any Lagrangian–Euler method to realize the simulation of micro-grinding temperature, gets the distribution of temperature field and changing situation during the micro-grinding through single-factor experiment and simulation analysis, and makes a study on the laws of different grinding depths, feeding rates, grinding velocities, different crystal planes {(001), (110) and (111)} and different crystal orientations in (001) crystal plane that affect the micro-grinding temperature, thus obtaining the crystal orientation which produces low grinding force and temperature. The result indicates that the grinding temperature increases with the increase in spindle speed, feeding rate and grinding depth; the grinding force and temperature are proportional to the elastic modulus and shearing modulus of the single-crystal material; the grinding temperature along (111) crystal plane is the highest, that of the (110) crystal plane is at the middle, and that along (001) is the lowest. When grinding in the (001) crystal plane, the normal grinding force and temperature along [110], $$ [\bar{1}10] $$ , $$ [\bar{1}\bar{1}0] $$ , $$ [1\bar{1}0] $$ crystal orientations are the highest, and those along [100], [010], $$ [\bar{1}00] $$ , $$ [0\bar{1}0] $$ crystal orientations are the lowest. And along with the aggravating of wear of abrasives on the grinding tool, the normal grinding force, tangential grinding force and grinding temperature all increase and the wear state of grinding tool can be judged online according to the signal of grinding force and temperature. These results provide an important evidence to do further research on the surface integrity of grinding single-crystal superalloy.