Common Causes of Oil-Film Bearing Failure
Two common causes of oil-film bearing failure are scoring and wiping. Scoring means there are circular grooves on the lining surface, and these grooves tend to be heavier at the load zone. Wiping means there is displacement of babbitt to another location.
Causes of scoring include internal or external abrasive contaminants in the lubricating oil or bearings running at faster speeds, which can speed up the abrasion process if there are contaminants. Another potential cause is a new bearing liner being installed on a scored or damaged shaft.
The degree of scoring or severity of scoring damage will depend on the bearing load, the shaft-surface finish, speed, and the particle size.
Wiping damage occurs when babbitt is displaced from the load zone to another place in the bearing. A common cause is babbitt melting due to the shaft or thrust runner coming into contact with the babbitt surface, which in turn can be caused by a temporary breakdown in the oil film and boundary lubrication.
Wiping can also be caused by too much peak pressure in the oil film, which can lead to localised plastic deformation of the babbitt.