A practical methodology to select fretting palliatives: application to shot peening, hard chromium and WC-Co coatings

Considered as a plague for numerous industrial assemblies, fretting, associated to slight oscillatory displacement, is encountered in all quasi-static contacts subjected to vibration. Depending on sliding conditions, cracking or wear damage can be observed. During the past three decades there has been a huge development in surface treatments. Thousands of new surface treatments and coatings are now available. The critical challenge is to evaluate such treatments against fretting loadings. To achieve this objective, a fast fretting methodology has been developed. It consists in quantifying the palliative friction, cracking and wear responses through a very small number of fretting tests. By defining quantitative variables, a normalized polar fretting damage chart approach is introduced. Applied to shot peening, chromium coatings and WC-Co coatings, it demonstrates the potential benefit of a thermal sprayed WCCo coating.