Confirming subsurface initiation at non-metallic inclusions as one mechanism for white etching crack (WEC) formation

White etching crack (WEC) formation beneath the contact surface in steel rolling element bearings causes a premature wear failure mode called white structure flaking (WSF). The drivers and initiation mechanisms are contested. Extensive work previously conducted by the authors showed strong evidence for one mechanism of WEC initiation being subsurface at inclusions. This paper conducts further work for final verification. Rolling contact fatigue testing of bearings on a FAG-FE8 test rig was conducted. Serial sectioning was used to map WECs in their entirety that formed under non-hydrogen charged conditions for the first time. Evidence from this paper and previous works by the authors confirms that subsurface initiation of WECs at non-metallic inclusions is at least one mechanism of WEC formation. (C) 2014 Elsevier Ltd. All rights reserved.