Bearing Shell Defects

Question 1

What is ‘Wiping’ and where is it found?

Answer 1

Bearing metal melts and is “wiped” from the surface of the bearing.
Less severe wiping is known as smearing because the surface appears to have been smeared.
Found on white metal of bearing.
Caused by loss of hydrodynamic lubrication leading to overheating.

Question 2

What is ‘Fretting’ and where is it found?

Answer 2

Caused by relative movement between bearing shell and housing.
May also cause cracking of bearing material as the relevant movement destroys bonding between shell and bearing material.
Found between bearing shell and housing.