Keywords

Rolling Bearings, Metallurgical Analysis, Load-Carrying Capacity

Track

Rolling Element Bearings/Wind Turbine Joint Session I (Session 5J)

Confirming Subsurface Initiation at Inclusions as One Mechanism for White Etching Crack Formation

White etching crack (WEC) initiation & propagation mechanisms are contested. WEC initiation mechanisms are suggested as surface initiation at cracks, subsurface initiation by inclusions, impact events, and damage accumulation followed by rupture causing microstructural change to release energy. Evidence for one mechanism of WEC formation being subsurface has been provided by the authors through serial sectioning to map subsurface wear volumes of bearings from service and large scale test rigs (non-hydrogen charged) and test specimens from laboratory (hydrogen charged). To verify a subsurface mechanism, RCF testing on a FAG-FE8 test rig was conducted (non-hydrogen charged) and serial sectioning used to map WECs in their entirety that formed under these conditions for the first time. Evidence from this investigation and the authors previous works confirms that subsurface initiation of WECs at inclusions is at least one mechanism of WEC formation.

Authors and Company/Institution

Martin -H. Evans, Ling Wang and Robert JK Wood, National Centre for Advanced Tribology at Southampton, University of Southampton, Southampton, UK
William B. Anderson, Afton Chemical Corporation, Richmond, Virginia