The effect of abrasive grain size on the transition between abrasive and adhesive wear

Experiments were carried out in which SiC abrasives with a grain size range of 3–150 μm were inserted between sliding metals. The metals were pure aluminium, copper, iron, nickel and zinc. The test geometry was a tube end against a flat surface. The effect of grain size can be classified into three regimes. In the first, where abrasive grains are larger than a critical size dc (about 50 μm), the wear rate is independent of grain size. In the second regime the wear rate decreases as abrasive grains become smaller than dc to a limit at a transition grain size dt (about 10 μm). In the third regime the wear rate is high and independent of abrasive grain size. The wear debris consists of large metal flakes with abrasive particles mixed in. Although abrasive particles are present, the wear is primarily adhesive, and the action of the abrasive particles is to promote the removal of metallic wear debris from the contact region.