Surface Temperatures in Grinding

Abstract Heat-transfer theory involving a moving heat source is applied to the grinding process to obtain an equation for the mean surface temperature in grinding. This equation predicts surface temperatures as high as 3000 F for a representative fine grinding operation. The analysis shows that in finish-grinding the surface temperature is reduced by decreasing the chip depth of cut but in snagging operations the surface temperature may be reduced by increasing the chip depth of cut. Representative values of the mean temperature between the chip and the grinding wheel obtained by the toolwork thermocouple technique are presented and discussed. The role of the grinding atmosphere in the production of sparks and in determining the energy involved in grinding is illustrated by experimental data. When the oxygen concentration of the atmosphere is very low, the specific grinding energy is found to be unusually high. The existence of high surface temperatures in fine grinding operations is demonstrated by the presence of a transformed surface layer that is largely retained austenite.