Fasteners include: bolts, studs, screws, nuts, washers, pins. Locked or bitten often occurs on stainless steel, aluminum alloy and titanium alloy fasteners, these metal alloy itself has anti-corrosion properties, will be damaged in the surface, the metal surface to produce a thin layer of oxide to prevent Further corrosion. When the stainless steel fasteners are locked, the pressure and heat generated between the teeth will damage the oxide layer, so that the metal thread between the blocking or shear, and then the phenomenon of adhesion. When this phenomenon continues to occur, will make the stainless steel fasteners completely locked, no longer can not be removed or continue to lock. Usually this series of blocking _ cut _ sticky _ locked a series of actions took place in just a few seconds, so the correct understanding of the use of such fasteners, can prevent this phenomenon.