Galling is a type of mechanical wear caused by a combination of friction and adhesion between sliding surfaces typically under a compressive load. It is the result of tearing and slipping of the crystal structure at the surface once the protective chromium oxide layer has worn away. Further mechanical forces cause the material to become stuck or welded to the mating surface, and ultimately results in the seizing of interfacing components. In the case of fasteners, this is problematic since a galled fastener assembly has to be drilled or cut to be removed.
Galling resistance in stainless steel metal–on–metal applications can be achieved through Bodycote’s Specialty Stainless Steel Processes (S³P) while preserving the corrosion resistance properties of the base material.