One of the major causes of premature failures of wind turbine gearing systems is the formation of axial cracks in wind turbine bearings. Increased surface stress results in increased subsurface stress, which in turn leads to a phase change in steel known as white etching areas (WEA). Cracks form in the steel within or at the edge of the WEA and these cracks lead to fatigue damage.
Afton Chemical has conducted research on the causes of white etching formation and the role of lubricants in controlling WEA. Afton observed that lubricants that can control surface stress by forming the proper tribofilm on a surface can control fatigue.
Afton Technical Advisor Mark Devlin presented on this topic during the 2015 AWEA O&M and Safety Seminar.