Investigations of Bearing Failures Associated with White Etching Areas (WEAs) in Wind Turbine Gearboxes

摘要

A critical problem for wind turbine gearboxes is failure of rolling element bearings where axialcracks form on the inner rings. Metallurgical analyses show that the failure mode is associatedwith microstructural alterations manifested by white etching areas (WEAs) and white etchingcracks (WECs). This paper presents field experience from operating wind turbines that comparesperformance of through-hardened and carburized materials. It shows through-hardened bearingsdevelop WEA/WECs and fail with axial cracks, whereas carburized bearings do not. In anothercomparison of two rotor bearings with different carburized metallurgies, one bearing developedWEA/WECs and failed by macropitting, whereas the other bearing did not develop WEAs or WECsand did not fail.