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 commercial tungsten carbide (WC) pin on silicon carbide (SiC) disks in order to determine the wear and friction data dispersion. The tests were repeated using two sliding speeds (v), 0.1 and 1.0 m/s, and two applied loads (P), 5 and 50 N. The wear data showed a dispersion in the range of 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 of 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.