White etching cracks: A result of bearing failures
This may cause a bearing failure, resulting in what is often described as white etching cracks (WEC), sometimes also called white structure flaking (WSF).
What are white etching cracks (WEC)?
The affected areas consist of ultra-fine, nano-recrystallized, carbide-free ferrite, or ferrite with a very fine distribution of carbide particles. These areas appear white under an optical microscope due to their low-etching response to the etchant. White etching areas around cracks are 10%-50% harder than the surrounding unaffected microstructure.
White etching areas (WEA) develop around cracks during overrolling. This means that WEC can be found not only in bearings that have failed prematurely, but also in bearings that have failed due to rolling contact fatigue (after a long running period). Because WEC are part of the crack networks in any failed bearings, they can be found in all types of applications, as well as in all standard heat treatments.
|All types of applications||All types of bearings||All standard materials and heat treatment|