Failure analysis of engine bearing

An engine bearing was failed during service. During inspection, ball and races of rear bearing were found with wear marks. The bearing was subjected to metallurgical failure analysis. Inclusion level in the balls of bearing was observed higher; these inclusions were rich in Mo and V. The inclusions being the potential sites of the stress concentration caused the subsurface fatigue cracks in the bearing balls. The bearing was failed due to the severe spalling produced under subsurface fatigue leading to the subsequent wear of the raceways. (author)