Cracks on Bearing Rings – 707 VI (IGF nr. 20881)


Influence of practice-oriented lubricant formulations on the formation of white etching areas and white etching cracks



In roller bearing applications, failures can occur long before the calculated fatigue life, which are related to the occurrence of white etching areas (WEA) or cracks (WEC). In the last decade, the focus of national and international research has been on the influence of contact conditions (esp. contact pressure, slippage condition and lubrication condition) and additional loads (esp. additional electrical load and hydrogen pre-loading) on the occurrence of WEA/WEC. As a result, a consensus has been reached on these topics to some extent. On the other hand, the lubricant influence is currently discussed in a very contradictory way. In addition, the understanding generated at the basic level in this regard does not provide any practical insights for the targeted development of lubricants or the optimization of entire tribological systems to prevent WEA/WEC yet. As part of the project series: "Cracks on bearing rings" the influence of practice-oriented lubricant formulations on the formation of WEC is currently being intensively investigated at MSE in the current project 707 VI (project designation within the Research Association for Drive Technology (FVA), part of the industrial community research (IGF, project number: 20881 N)). The factors taken into account are shown in the following figure.


Research goals

The primary goal of the research project is to understand and be able to evaluate the encouragement of the emergence of WEA/WEC by different lubricant formulations. Sub-goals of the project are:

  • Derive a screening method to evaluate the encouragement of WEA/WEC development of a lubricant formulation
  • Identify WEA/WEC-critical lubricant formulations and differentiate the extent to which they promote or affect WEA/WEC development
  • Identify and understand relationships between lubricant formulation, triboreaction and -mutation layer formation, hydrogen input, and WEA/WEC formation
  • Identify alternative additives of the same additive group to modify a lubricant formulation toward no/less encouragement to WEA/WEC development
  • Demonstration of the transferability of findings between different test rigs for the same conditions

Research and project partners

  • IWM - Institute for Materials Applications in Mechanical Engineering, RWTH Aachen University
  • GFE - Joint Laboratory for Electron Microscopy, RWTH Aachen University

Funded by

Federal Ministry of Economic Affairs and Climate Action Copyright: © BMWK
  • Federal Ministry of Economic Affairs and Climate Action

Project sponsor

Copyright: © FVA
  • Research Association for Drive Technology (FVA)