Influence of electrical discharge machining on the reciprocating sliding friction and wear response of WC–Co cemented carbides

The dry friction and wear behavior of a number of WC–Co cemented carbides, exhibiting 6 up to 12 wt.% cobalt as binder phase and average carbide grain sizes ranging from 0.3 up to 2.2 μm, combined with various surface finishing variants of wire electrical discharge machining (EDM), was evaluated by performing linearly reciprocating pin-on-flat sliding experiments against WC–Co cemented carbide using normal contact loads of 15 N up to 35 N and a sliding velocity of 0.3 m/s. Post-mortem obtained wear volumes and volumetric wear rates were correlated to real-time recorded penetration depth curves versus sliding distance. Consecutive execution of gradually finer EDM regimes onto the WC–Co alloys was found to considerably enhance the wear performance. Scanning electron microscopy on the worn surfaces revealed the occurrence of several wear mechanisms, i.e., grain polishing, abrasion, grain cracking and surface binder removal, mainly depending on the original surface finish EDM regime.