Data supporting: Scuffing mechanisms of EN-GJS 400-15 spheroidal graphite cast iron against a 52100 bearing steel in a PAO lubricated reciprocating contact

This data supports the following publication (see below for paper abstract):Kamps, T.J., Walker, J.C., Wood, R.J., Lee, P.M. and Plint, A.G. (2017) Scuffing mechanisms of EN-GJS 400-15 spheroidal graphite cast iron against a 52100 bearing steel in a PAO lubricated reciprocating contact. Wear, 1-16Scuffing of the automotive piston ring on liner contact is likely to increase due to engine downsizing and the use of low viscosity engine oils to achieve greater fuel efficiency. This work investigated the scuffing mechanism of EN-GJS 400-15 spheroidal graphite cast iron caused by reciprocating sliding of a 52100 roller bearing element lubricated with PAO base oil. The contact was conditioned at 100N and 15 Hz over a stroke of 25 mm at 180 oC. Subsequently the load was incremented in 100 N/min steps at 5 minute intervals until severe scuffing occurred, indicated by a rapid rise in the average friction coefficient. High speed friction was used to determine the onset of mild and severe scuffing. Stylus and 3D optical profilometery revealed that mild scuffing produced a smooth surface with small cracks compared to the severe scuffed surface which contained adhesive wear craters of 40 ?m in depth. Focused ion beam cross-sections of the mild scuffed surface and EDS analysis of the microstructure indicated that cracks were initiated by dross inclusions with a similar morphology to flake graphite. The transition to severe scuffing occurred at 700N when crack networks facilitated adhesive transfer of cast iron material to the counter-surface.