Friction and wear behaviour of cemented carbides

In this paper the friction and sliding wear of WC–Co cemented carbides are studied. Friction and wear tests were carried out using six different WC–Co alloys (Co ranging from 6 to 20 wt.%) under unlubricated conditions against steel (0.45 wt.% C) disk. Tests were performed at sliding velocity of 2.2 m s−1 and normal load of 40 and 180 N. Sliding wear tests were carried out using moderated block-on-ring equipment. It is shown that wear resistance depends on the chemical composition and hardness of cemented carbides. The wear rate of cemented carbides decreases with an increase in hardness and decrease in binder content. Means, standard deviations (S.D.) and COV of wear data were calculated. The morphological analysis of the worn surface and wear debris were made by SEM. The wear mechanism has a complicated character and depends on the applied load and material composition. The wear of WC–Co cemented carbides under dry conditions is caused mainly by removal of the cobalt binder followed by fracture of intergranular boundaries and fragmentation of carbide grains.