The Use and Misuse of the Pin-on-Disk Wear Test
The pin-on-disk (PoD) wear test remains one of the most widely-used in materials tribology. An ASLE survey published in 1976 exemplifies its historical use. Like any wear test method, the deceptively simple PoD has both advantages and disadvantages. This presentation overviews the use and the all-too-common misuse of the PoD test method. Topics will include its relevance to engineering components, the effects of pin tilt and alignment on cutting versus plowing, varying contact area ratio for conformal versus non-conformal contacts, non-constant sliding distance and contact pressure due to track widening, third-body effects from the orientation of the disk, and differences in results depending on whether a material is chosen for the pin or disk specimen. The repeatability of PoD data and the presumption of linear wear behavior when computing wear coefficients is addressed, as is the question of whether the popular ASTM G99 standard PoD test is really a standard.