What are galling and seizing?
Galling and seizing are two fairly common complaints about threaded fasteners. Galling happens during fastener tightening. It is most prevalent with fasteners made of stainless steel, aluminum, titanium, and other alloys that generate an oxide surface film for corrosion protection. During fastener tightening, pressure builds between the contacting thread surfaces, protective oxides break down, and high points shear or even lock together. The cumulative action of these processes causes increased adhesion and difficulty in tightening results (galling). At the extreme, this can lead to seizing, the freezing together of the threads. Continued tightening causes the bolts to break or have their threads ripped out. Thread lubrication has been found to be helpful in relieving galling. Lubricants that contain molybdenum disulfide, graphite, mica, talc, or wax seem to help best. Keep in mind that the torque-tension relationship will be altered with the application of a lubricant and you may have
