The influence of surface crack on the wear behavior of polyamide 66 under dry sliding condition

The effect of surface crack on the wear of polyamide66 sliding against steel counterface in dry condition was investigated in pin-on-plate reciprocating testing machine. The test rig was designed to perform wear tests under constant and fluctuating loading conditions at constant sliding speed for most of the stork. Effects of crack orientation, under different static and cyclic loading parameters, on wear behavior were examined. Relative change in wear rate due to surface crack existence, as well as crack orientation, was studied to provide understanding of surface fatigue wear. There was consistent evidence of the effect of surface crack on the wear rate under static and cyclic loading conditions. A single perpendicular crack on the rubbing surface results in high wear rate specially during running-in period. Polymer wear showed a higher sensitivity to surface crack under cyclic loads rather than static loads. The correlation between running-in wear and pre-existing surface cracks explained as a process of “severe” or “progressive” surface fatigue wear. Results of the present study provide a basis for assessing the fatigue wear resulting during the wearing-in period from pre-existing surface crack defect.