Fretting Wear and False Brinelling
Fretting wear and false brinelling: Fretting
is friction wear of components at contact points caused by
minute oscillation. The oscillation is so minute that grease
is displaced from between parts but is not allowed to flow
back in. Localized oxidation of wear particles results and
wear accelerates. In bearings, this localized wear appears
as a depression in the race caused by oscillation of the
ball or roller.
The depression resembles that which occurs
during Brinell hardness determination, hence the term false
brinelling. An example would be fretting wear of
automotive wheel bearings when a car is transported by
train. The car is secured, but the vibration of the train
over the tracks causes minute oscillation resulting in false
brinelling of the bearing race.