WEAR FAILURE AS INFLUENCED BY EXTERNAL STRESSING

Under the assumption that wear failure is actually a surface failure caused by stressing of materials at their outermost fibres, it has been postulated herein that stressing materials during a wear process by imposing external normal stresses will eventually affect the stress state at the material surfaces within the contact zone and consequently may affect the wear behaviour. A specially designed test rig has been used to test brass (copper-based alloy) specimens subjected to tensile loading under different loads and for different prolonged intervals of time. The rig is a modified version of the crossed cylinder type of wear-testing machine. Wear test results reveal that stressing specimens at load below the yield point affects the wear behaviour to some extent. It is concluded that superimposing external tensile stresses on a loaded specimen rubbing against a rotating steel shaft influences the wear behaviour. The wear rate will be reduced to a minimum value when the resultant axial stress reaches a minimum value or even diminishes.