Galling is a phenomenon wherein unexpected adhesion occurs between two metal surfaces in sliding contact, resulting in frictional damage or ultimately seizing.<\/p>\n
This type of adhesive material wear<\/a> poses serious risks as it may lead to costly maintenance<\/a> from repairs or equipment failure. Thus, unchecked galling can in turn lead to unwanted production delays, using up time and resources significantly.<\/p>\n Let’s delve into the causes, effects, and preventive measures for galling.<\/p>\n Galling occurs when two surfaces in relative motion start sticking to each other through molecular forces, eventually resulting in accidental cold welding. It is quite a common problem in metal forming<\/a>, hydraulic cylinders, bearings, engine pistons, threads, and other applications where metal surfaces are in sliding contact. Metal galling is especially prevalent when there is insufficient lubrication between the surfaces.<\/p>\n This adhesive wear typically occurs when subjecting the materials to high loads and slow sliding speeds, but it also occurs in high-speed applications with little loads. Add temperature and poor lubrication into the mix and the galling effect only gets stronger.<\/p>\n Some metals are more prone to galling than others, aluminium and austenitic steel for example. Typically, softer materials gall easier and harder materials are more resistant. Properties that affect the material’s ability to gall are plasticity and ductility<\/a>. Galling can happen regardless if the metals in contact are the same or different. Brass and bronze are preferred for situations where sliding occurs (bearings<\/a>, bushings) as they are rather resistant to galling.<\/p>\nWhat Is Metal Galling?<\/h2>\n