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PLAIN BEARING FAILURE
3.0 Fatigue
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3.1 Fatigue of White Metal Journal Bearing
3.2 Fatigue of White Metal Journal Bearing Caused by Vibration
3.3 Premature Fatigue of a White Metal Journal Bearing
3.4 Fatigue Failures: Summary
White metal bearing alloys have low strength and readily suffer fatigue damage when subject to reversing loads, such as occur in reciprocating machines (engines, reciprocating compressors, ram pumps), and also when subject to vibration caused by out-of-balance or dynamic instabilities.
White metals are always used as a lining on a backing of a harder material, usually mild steel, but more rarely bronze. The fatigue strength of the white metal can be increased by reducing the thickness of the lining, but with the penalty of reducing the conformability and embeddability of the bearing material.
White metal thicknesses of 1 to 3 mm (thick wall bearings) are most commonly used in industrial machines; this not only gives good conformability and embeddability, but may also provide a molten layer that allows a machine to be run down safely in the event of failure without damage to the rotor. Thick wall bearings can be repaired by re-metalling. Thin wall bearings with white metal linings in the range 0.08 to 0.12 mm are only used in reciprocating applications, in particular high-speed engines, to give enhanced load-carrying capacity; these bearings cannot be repaired.
See thermal fatigue (Section 7), mechanical erosion (Section 2), and cavitation erosion (Section 4), which are other forms of fatigue damage and are treated separately.