Abstract: Fretting tribological tests of fluorine rubber (FKM) against stainless steel under varied normal loads and displacement amplitudes are carried out on UMT multi-function friction and wear tester. Running behavior, wear mechanisms and the damage process induced by fretting wear are studied based on the dynamic analysis as well as the scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis of worn surfaces. The results show that the fretting running behaviors of FKM can be defined by three fretting regimes (i.e. partial slip regime (PSR), mixed fretting regime (MFR) and slip regime (SR)) with the increase of angular displacement amplitudes. The contact load change fretting running regimes obviously, with the increase of contact load, it is hard to change from PSR to MFR and SR, and the area of PSR and MRF enlarged. Similar to torsional fretting, MFR of FKM elastomer is decided by combined the variation of Ft-D curves with the evolution of damage morphologies. In different fretting running regimes, the evolution of friction coefficients (Ft/Fn) and damage characteristics is different. In PSR, surface damage of FKM is slight. In MFR and vicinity, the main surface damage of FPM is the initiation and propagation of cracking, surface delamination and pitting, partial wear. In SR, the specific pattern wear for rubber material is presented on worn surface. In addition, in both MFR and SR, tribo-oxidization of FPM is obvious.

Key words: damage mechanism, fluorine rubber, fretting wear, O-ring, reciprocating shaft seal