The Fretting Wear of Nitrogen-Bearing Austenitic Stainless Steel at Temperatures to 600°

Abstract

The fretting behavior of the nitrogen-bearing austenitic stainless steel, Nitronic 60, has been studied at 20, 400, 500, and 600°C in air. A spherical ended rider was vibrated against a flat specimen, both machined from the steel. Normal load was 3N, frequency 50Hz and peak-to-peak amplitude 40 μm. Coefficient of friction after 106 cycles showed a decrease as the temperature was increased, falling from 0.62 at 20°C to 0.10 at 600°C. Wear volume also dropped dramatically at 400° and above, with no measurable wear at 600°C. A smooth protective oxide was formed at 400, 500, and 600°C, typical of the glaze oxide previously found on nickel-based alloys. The oxide layer was approximately 10 μm thick and had the spinel structure. The electron diffraction pattern most closely resembled that of the spinel NiO, Cr2 O3 but chemical tests showed that it contained iron. It is thought to be a mixed spinel containing all three metal ions.