Wear mechanisms and transitions in advanced railway materials - a twin disc benchmark of Mn13, CrB1400 and R400HT

Abstract

Twin disc tests are performed to determine the wear behaviour of three advanced crossing materials. In particular, the austenitic Hadfield steel Mn13, the ultrafine-pearlitic R400HT and the chromium bainitic CrB1400 steels are benchmarked. The investigated crossing materials are combined with the standard wheel material ER7. The tests are performed under two different contact pressures, 1 400 and 1 800 MPa, respectively. Dry conditions and a slip of 0.5% are used. The parameters evaluated are: wear rates, wear debris, plastic deformation, microstructural changes, friction coefficient and material hardness. R400HT is identified as exhibiting the highest wear resistance, although CrB1400 shows comparable results. Mn13 exhibits the highest wear rates. Three primary reasons for the elevated wear rates of Mn13 are identified. These include a significantly lower initial hardness, a distinct hardening mechanism in conjunction with a high work-hardening potential and a different wear mechanism that shows a high dependence on the applied contact pressure. The different wear mechanism is expected to be the main driver for the high wear rates.