Plain bearing failure index

2.0 Wear

Wear Index


2.2 Scoring of white metal journal bearing

Click on photograph to enlarge
	Dirt particles embedded in bearing surface
Main Characteristics	Score marks in white metal surface ending in an embedded foreign particle
Cause	Contamination of the lubricant with hard particles small enough to enter the oil film at the point of maximum film thickness, but too large to pass right through without bridging the film. See wear summary for further information on causes and actions.
Note	The embedded particles may be analysed to identify the source of the contamination. For example, iron or steel particles can be identified by iron printing using absorbent paper soaked in potassium ferrocyanide solution.
Possible Confusion with Other Types of Damage	With scoring due to damage to the journal surface there will be no embedded particles within the bearing material and the scores may be continuous around the bearing circumference.
Comment	Scoring damage indicates inadequate filtration of the oil or failure to change the oil filter when necessary.

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