Wear In Lubricated Journal Bearings

If the combination of bearing material, lubricant, and journal material is well chosen, wear in lubricated journal bearings has a mildly abrasive character, the asperities of the journal surface slowly grinding away material of the inner surface of the bearing. It is shown that this process can be simulated adequately on a pin-and-ring apparatus. Experiments performed on such equipment show that the specific wear rate of bronzes, white metals, aluminum-tin alloys, copper-lead, zinc-aluminum and copper-aluminum increases linearly with increasing surface roughness of the mating component, i.e. a journal made from carburized steel AISI 5120 with a Vickers hardness of 680 · 10⁷ N/m². It is also shown that, when in contact under conditions of boundary lubrication with copper-tin, copper-aluminium, copper-lead, lead babbitt or tin babbitt the roughness asperities of the hard steel journal gradually disappear by a polishing process. This effect does not occur if the steel journal is in contact with either aluminium-tin or zinc-aluminium. The effect is tentatively explained in terms of an electrochemical interaction between the nonferrous alloys and the steel.