On data dispersion in pin-on-disk wear tests

Ten pin-on-disk sliding wear tests for each experimental condition were carried out with a WC pin on SiC disks in order to determine the wear and friction data dispersion. The tests were repeated using two sliding speeds, 0.1 m/s and 1.0 m/s, and two applied loads, 5 N and 50 N. The wear data showed a dispersion in the range 28-47% and 32-56%, for disk and pin, respectively. For the disk, the dispersion decreased when increasing both sliding speed and applied load; for the pin, no clear relationship was found. The friction values spread in the range 5-15%, with a lower dispersion at high applied load, independent of the sliding speed. From a statistical point of view, it was found that, in all the experimental conditions adopted, about 20% of the wear and friction values can be considered outliers.