KEYWORDS

Wear: Rolling-Contact Fatigue, Surfaces: TDS, Surfaces: Metallurgical Analysis

INVESTIGATION OF THE ROLE OF HYDROGEN IN WHITE STRUCTURE FLAKING (WSF) OF WIND TURBINE GEARBOX BEARINGS

White structure flaking (WSF) due to white etching crack (WEC) formation below the contact surface is found to cause premature wind turbine bearing failures. Initiation mechanisms and drivers of WSF are not fully understood. Hydrogen diffusion into the bearing steel during operation is thought to be one of the driving factors of WSF. Using Thermal desorption spectroscopy (TDS) this study analyses the diffusible hydrogen content found in bearings subjected to rolling contact fatigue (RCF) on an FAG-FE8 test rig under Non-hydrogen charged test conditions TDS results show that the concentration of diffusible hydrogren increases with RCF test duration and hydrogen diffusion has occured through wear induced nascent surfaces. Serial sectioning analysis on bearing rollers with different diffusible hydrogen concentrations is being conducted and the intital serial sectioning shows evidence to suggest that increase in diffusible hydrogen concentration may be related to the WEC formations.

AUTHORS

Alexander Richardson, Ling Wang, Robert J.K. Wood, Martin H. Evans, University of Southampton, Southhampton, UK, William Anderson and Marc Ingram, Afton Chemical Corporation, Richmond, VA