Lube-Tech PUBLISHED BY LUBE: THE EUROPEAN LUBRICANTS INDUSTRY MAGAZINE
No.159 page 1
Breaking the cycle of white etching cracks: How copper- based additives solve one of industry’s most puzzling bearing failures
Rafe Britton, Consultant, Lubrication Expert, Sergei Mamykin, Scientific Advisor- NEOL Copper Technologies, and Marc Ingram, Engineer at Ingram Tribology Ltd
A persistent problem in power and motion Despite decades of research and steady improvements in bearing design, lubricant formulation, and contamination control, White Etch Cracks (WECs) continue to undermine the expected service life of rolling element bearings. In wind turbine gearboxes, in particular, these subsurface cracks are now recognised as one of the leading causes of unexpected bearing damage. Studies have shown that up to half of bearing failures can be traced back to lubrication- related issues, and yet even machines that are properly lubricated, carefully aligned, and maintained to OEM specifications still suffer from WEC-related failures.
These failures are particularly frustrating because they do not follow the typical progression of surface- initiated damage modes like abrasive wear, adhesive wear, or classical rolling contact fatigue. Instead, they originate deep below the surface, where stress concentrations and microstructural changes lead to the formation of cracks that only later manifest as surface spalling or flaking. Under metallurgical analysis, these cracks are surrounded by White Etch
Areas (WEAs)—regions of transformed steel that appear white under etching due to their altered composition and grain structure. When these cracks propagate to the surface, they result in White Structure Flaking (WSF), leading to material loss and eventual bearing failure.
The consequences of WEC failures are far-reaching. In wind energy, they result in extended downtime, costly crane mobilisations, and lost electricity generation. In transportation, they raise safety and reliability risks. In all sectors, they contribute to maintenance unpredictability and increased life cycle costs.
What makes WECs even more challenging is the lack of consensus around their root cause. Once considered rare anomalies, they are now recognised as a recurring and systemic problem across multiple industries and bearing types. Two major schools of thought have dominated the conversation. The first attributes WECs to purely mechanical factors such as high contact stress, sliding, vibration, and material fatigue. In this view, WECs are seen as a subsurface
LUBE MAGAZINE NO.188 AUGUST 2025 29
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64
