New test method and apparatus for measuring galling resistance

Galling is a severe type of wear that can occur when relative motion exists between contacting surfaces. It is characterized by surface protrusions an d an increase in surface roughness of one or both components. Galling can o ccur vary rapidly; under certain mating conditions it can occur in as littl e as one cycle and can even lead to the eventual seizure of mating componen ts. In this study, a new test method and apparatus for measuring the gallin g resistance of mated materials was developed. Tests were conducted on self -mated stainless steel to determine the threshold galling stress. The new t est method requires the use of two specimens, namely a stationary button an d a rotating cylinder. The end of the stationary button contacted the rotat ing cylinder along the cylinder's length, thereby creating line contact. Ga lling occurred along the line of contact when the cylinder was rotated and the load between the specimens was increased. The threshold galling stress was calculated using force measurements from a load cell on the stationary button. In addition to measuring the force between the specimens, the torqu e required to rotate the cylindrical specimen was measured in order to dete rmine the frictional force between the cylinder and button. (C) 2001 Elsevi er Science Ltd. All rights reserved.