An Experimental Study on the Impact of Interface Temperature on Thermally Induced Wear Transitions in Dry Sliding

Abstract

Premature failure of materials in sliding contact is often a result of the buildup of frictional heat at the contact interface. The interface temperature is an important parameter affecting the friction and wear process, and it is a function of the operating conditions as well as the heat that is dissipated through the material pair and the nearby surroundings. Possible solutions to alleviate thermal wear mechanisms include using more thermally robust materials and providing better cooling or heat dissipation to reduce the elevated temperatures. The latter is the subject of this paper. The micro heat sink ring (μHSR) is a patented approach to interface cooling in which a micro heat sink is constructed within millimeters of the contact interface. The ramifications of this are that temperature can be treated during wear testing as an independent variable and is only a very small function of speed and load. Using this approach, this work investigates the impact of the μHSR on the wear behavior of a tungsten carbide and carbon graphite material pair under dry running conditions at various rotational speeds and face pressures. Ring-on-ring experiments are performed using a thrust washer rotary tribometer within and in excess of the PV limit of the material pair (17.5MPa*m∕s). Results show the potential of the μHSR to allow for reliable operation of materials in sliding contact in harsh operating conditions. The ability to reduce the interface temperature shows a shift in the region of acceptable operating parameters normally defined for the material pair. This shift is attributed to the prevention of the onset of thermally induced wear transitions and thermal failures otherwise prone to occur under certain operating conditions.