Fatigue superficielle des pièces en frottement. Influence des traitements de surfaces^*

Friction parts of superficial fatigue

Centre Stéphanois de Recherches Mécaniques, Hydromécanique et Frottement Andrezieux Boutheon

Résumé

Abstract

Superficial fatigue phenomena are essential for the reliability of numerous mechanical parts with surfaces exposed to repeted friction sollicitation (gears, cams, lift rods...).

In order to give access to a precise study of these phenomena, a test machine and methodology have been designed, allowing :

- on one hand, to give account of the influence on the lifetime of the mechanical effects ;

- on the other hand, to study (in quality and in quantity) the numerous parameters involved in these mechanism.

After the description of the principle of employed test machine and methodology, results are presented about the study of the influence on superficial fatigue of various kinds of surface treatments. These results are applied to the problem of improving the lifetime of white cast iron cams for automotive engines, and of highly sollicited case-hardened iron gears.