been undertaken on a twin-disc rolling-sliding test machine with both oil and water
lubrication. Furrows and dents were artificially introduced into the disc surfaces, and surface
microcracks and pits were monitored by means of surface replication. The results showed
that artificial dents only reduce the fatigue life of the contact with oil, but not water lubrication.
With oil lubrication the fatigue failure initiates at the surface defect. However, with water as a …