A systematic investigation of grooving and rolling abrasive mechanisms using surface topography

Rolling and grooving are typical phenomena observed in ball cratering tests. Despite extensive research, their impact on the wear rate remains a subject of debate. Besides, the identification of rolling and grooving is predominantly performed with qualitative analysis. Therefore, this investigation introduced a systematic methodology for the assessment of the worn surface topography. Ball cratering tests were performed with increasing load to induce the transition between rolling and grooving mechanisms. Several roughness metrics were analysed, among which the surface aspect ratio (Str) was found the most effective parameter for identifying the transition between rolling and grooving. Additionally, the transition was found to occur in a range of load conditions. Moreover, a segmented analysis was implemented and further revealed a propensity for grooving to manifest towards the centre and trailing edge of the wear crater. Finally, it was found no discernible difference in the wear rate between rolling and grooving conditions, and different hypotheses were discussed to explain this behaviour. The superposition of mechanisms and the occurrence of grooving by rolling was found plausible explanations for the similar wear rate. As consequence, an improved terminology for rolling and grooving was proposed. The term rolling refers to the micro abrasive mechanism, while grooving designates the resulting failure mode.