White Etching Cracks
Influence of Load Conditions in Rolling Element Bearings on the White Etching Cracks (WEC) Damage Mechanism
White Etching Cracks (WEC) are parallel or branching cracks under the raceway surface of rolling element bearings. When etched, the crack flanks appear white, indicating a change in microstructure. WEC cause bearings to fail long before reaching their calculated lifetime. It is still unclear what mechanisms cause WEC formation and which mechanical, thermal, and chemical factors facilitate or impede it.
For research purposes, the complex load conditions in a rolling element bearing are simulated in a simplified compression-torsion experiment. This is expected to provide insights as to how WEC formation is influenced by stress conditions, changes in the material, and incipient cracks. Furthermore, failed bearings are analysed with fractographic and metallographic methods. If WEC are found, they are characterised in terms of crack structure and material properties.
 S. Averbeck, S. Wiesker, A. Smirnov, G. Poll: White Etching Cracks – neue Ansätze in der Ursachenforschung. 11. VDI-Fachtagung Gleit- und Wälzlagerungen 2015 (VDI-Berichte 2257), S. 273-284
Lehrstuhl für Maschinenelemente und Getriebetechnik (MEGT), TU Kaiserslautern
Institut für Maschinenkonstruktion und Tribologie (IMKT), Leibniz Universität Hannover
Contact: Dipl.-Ing. Stefan Averbeck