Investigation of the effects of skewness R_sk and kurtosis R_ku on tribological behavior in a pin-on-disc test of surfaces machined by conventional milling and turning processes

Abstract

Friction and wear are influenced by the surface conditions of the material, since there is deformation, segregation, generation of oxide films, among others. Roughness is an important characteristic in tribological studies, where the parameters of skewness and kurtosis have greater influence than the conventional parameters R_a and R_q. This study is aimed to investigate the influence of the parameters of skewness R_sk and R_ku kurtosis on the surface of the USI AR 360 steel machining by the milling and turning processes in the pin-on-disc sliding wear test. Results showed that surfaces with the same R_a and R_q could be distinguished by the skewness parameter. Different behaviors were observed in the analysis of friction curves, where the skewness effect showed a tendency to reduce the friction coefficient. It was also observed that the feed marks orientation in relation to the sliding direction can influence the tribological behavior of the surfaces.

Keywords:
Friction coefficient; Wear coefficient; Roughness; Skewness; Kurtosis; Asperities; Tribology