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Galling is the term used when two surfaces in contact seize up as a result of cold welding. The problem (also known as 'adhesive wear') is most commonly seen when tightening bolts made from materials such as stainless steel, aluminium or titanium. These materials gain their corrosion resistance from a passive oxide layer over their surface. Under high contact-force sliding this oxide can be deformed, broken and removed from parts of the component, exposing bare reactive metal. When the two such surfaces are the same materials, these exposed surfaces can easily fuse together, causing seizure or galling. In threaded bolts the galling leads to freezing of the threads, and applying further tightening force may simply shear off the head of the bolt, or strip the treads.
There are three suggested methods for avoiding the problem:
For more information please email:
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