Determination ofinterfacial temperatures under extreme pressure conditions

Interfacial temperatures attained in a pin and v-block apparatus under extreme pressure (EP) conditions were measured using pins made from either copper or an aluminum alloy from the asymptotes in the curve of removal rate versus applied load since these have been shown to correspond to the temperatures at which the interfacial material melts. The interfacial temperature rise was proportional to the applied load, where the proportionality constant a = A# where # is the interfacial friction coefficient and A a geometrical constant which has been previously measured for steel pins and v-blocks lubricated by chlorinated hydrocarbons dissolved in a poly a-olefm as 2.3 40.3 K/N. Values of A measured when using the aluminum alloy (2.4 40.1) and for copper (2.1 -40.2) were in good agreement with this measurement and indicated that interfacial temperatures in excess of 1000 K can be attained during EP lubrication. Finally, the rate of material removal in the pin and v-block apparatus can be related to the metallurgical properties of the pins.