Structural Changes Induced by Rolling Contact Fatigue – Results from Rig Testing and Field Experience

Abstract

Abstract Rolling element bearings are highly stressed in the contact area. For the design of these bearings both the knowledge of the acting contact stress and material and application specific stress limits are important. Data about stress limits are typically derived from rig testing results. Besides a statistic evaluation of life tests also an X-ray diffraction analysis of tested bearing components is possible. An X-ray analysis enables the detection of structural changes during the overrolling process. This kind of analysis can also be performed on bearings after use in field. A comparison between evaluation results from rig testing and from field experience enables the possibility to check the transferability from rig testing to the use in field. Several fatigue-exposed bearing components coming from different kinds of testing, were evaluated by X-ray diffraction analysis. Also, components from aeroengine bearings after use in field are investigated. All these bearing parts are made from M50, a high-speed steel which is used in critical aeroengine bearing applications. By comparing results from rig testing with results from use in field, it can be demonstrated, that it is possible to transfer findings from rig testing to the use in field.