Development of a galling resistance test method with a uniform stress distribution

In this study, a new galling test method is presented along with results from a pilot testing program. The pilot program was performed on type 303 stainless steel. The new testing configuration consists of two concentrically aligned hollow cylindrical specimens loaded along their longitudinal axes. The specimens are held in alignment using a custom made alignment pin. The pin maintains concentricity between the mated surfaces while enabling the contact interface to self-align. The resulting contact surface is in the shape of an annulus and has a uniform stress distribution. The new testing configuration eliminates the stress concentration that exists in the ASTM G98 Standard Test Method for Galling Resistance of Materials. The results of this study show that the galling wear phenomena do not transition from non-galled to galled at a single value. Galling is shown to be stochastic in nature.