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When surfaces move in relation to each other, this relative motion can result in abrasion. This abrasion can increase the attack at these fraying surfaces.
Fretting corrosion is an attack that is accelerated by the relative motion of contacting surfaces.
Fretting corrosion is usually a combination of corrosion and abrasive wear. The motion between the surfaces removes protective films and results in accelerated attack. Also, most corrosion products are abrasive and their presence increases the removal of protective films and in direct abrasion of the metal.
Fretting was common in riveted joints on ships and other riveted structures where cyclic loads were experienced, but this has largely been eliminated through welded construction. Fretting is, however, still encountered in bolted joints and flanges where there is not enough bolt tension to eliminate movement in the joint. Thermal expansion with frequent cycling can also result in fretting attack. Any combination of corrosion and wear will almost always be worse than the action of either one separately.
Fretting corrosion usually results in scuffed surfaces in joints or at other wear sites. If inspected soon after the relative motion ceases, the surfaces will often be bright and have corrosion products attached to the surfaces.
There are no standard tests for fretting corrosion. When encountered, it is addressed through mechanical design rather than material selection. Where it cannot be eliminated it can sometimes be reduced by using inhibitive caulking compounds in the joints.
: "Corrosion Control" NAVFAC MO-307 September 1992
Source : "Corrosion Control" NAVFAC MO-307 September 1992
|Fretting Corrosion in Airframe Riveted and Pinned Connections||Tribological parameters governing fretting as well as the effects of intereference and clamping on fretting wear and fretting fatigue have been evaluated using 2-D and 3-D finite element analyses|