Correlation between standard roughness parameters skewness and kurtosis and tribological behaviour of contact surfaces

The aim of the present research was to investigate the correlation between surface roughness parameters and friction. For this purpose 100Cr6 steel plate samples were prepared using different grades and combinations of grinding and polishing in terms of similar Sa but different Ssk and Sku values. Dry and lubricated pin-on-disc tests, using different contact conditions, were carried out, using Al2O3 ball as counter-body. Test results show that surfaces with higher Sku and negative Ssk values tend to reduce friction.

► This paper investigates correlation between roughness parameters' skewness and kurtosis and tribological behaviour.
► Standard roughness parameters Sa and Sq are not sufficient to determine the tribological properties of contact surfaces.
► Roughness parameters Sku and Ssk were found to show good correlation with tribological properties.
► The most dominant parameter is parameter Ssk. More negative it is lower the friction we can expect, even at higher average surface roughness. Friction also tends to get lower when parameter Sku is getting higher.
► Surface roughness parameters Sku and Ssk can be used for planning surfaces with desired tribological behaviour.