Structural Changes in Roller Bearings resulting in Early Crack Formation

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Thomas Janitzky © Copyright: IWM


Thomas Janitzky

Head of Division Learning


+49 241 80 95333




Recently, increasingly reporting of premature bearing failures in different applications can be observed. The failure mechanism and the crack-induced failures cannot be explained by the classical rolling contact fatigue mechanisms and therefore cannot be predicted using the classical life calculation methods according to DIN ISO 281 or DIN 26281. The damage pattern is characterized by the appearance of mostly undirected cracks below the surface of the raceway, which are bordered by White Etching Areas, WEA, and ultimately lead to cracking or spalling of the raceway. The breakdown of the machine or the whole system due to this premature failure of the bearing is a common cause for maintenance and downtime. As a result to ongoing research, there are different damage hypotheses concerning the described damage pattern of the White Etching Cracks, WEC. To the present state of knowledge, it is assumed that during the rolling load, an additional factor is required in order to provoke the damage.


  • Understanding of the damage mechanism
  • Evaluation of existing failure hypotheses and their improvement


  • Identification of pre-stages leading to the formation of WEA/WEC failure
  • Improvement of existing failure hypotheses
  • Assessment of influencing factors and identification of thresholds
  • Assessment of Condition-Monitoring systems
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