Rolling-sliding wear of austempered ductile iron with different strength grades

Austempered ductile irons (ADIs) with three strength grades were matched with high-carbon-chromium bearing steel and the rolling-sliding wear tests under high contact load were conducted on an Amsler type tribotester. During tests the contact surface was cooled by dry compressed air of 0.6 MPa to prevent the surface oxidation by heating. The wear properties and behaviors of these friction pairs were investigated. The results show that the wear mechanism is delamination and the delamination of ADIs becomes mild with the increase of material hardness. The friction coefficient of the test pairs increases with the increase of material hardness and the surface microhardnesses of ADIs increase greatly during the tests due to the martensite transformation. The wear rates of three strength grades of ADIs show no obvious difference and the wear rates are influenced by both the material hardness and the friction coefficient.