Spalling Failure Analysis of Bearing in Aero Engine

Fatigue spalling occurred to a bearing of an aero engine during service. Macroscopic examination, chemical analysis, mechanical property testing, metallographic examination, energy spectrum analysis were carried out to analyze the spalling cause of bearing inner raceway. The results show that forging burning had occurred to the bearing inner ring and formed hole defects, destroying the continuity of metal and reducing the contact fatigue strength of bearing. Under the effect of alternating stress, the hole acted as the core, resulting in the butterfly structure around it. Then micro cracks initiated and expanded to the rolling contact surface, resulting in spalling and causing the fatigue failure. By controlling the forging process and increasing the forging defects detection means to prevent forging burning, the service life of the bearing can be prolonged.