Friction and Wear Performance of High Carbon Grey Cast Iron

Abstract

In this paper, the friction and wear properties of gray cast iron with different carbon content at different ambient temperatures and the failure forms of gray cast iron friction and wear are studied, which has a certain guiding significance for the manufacture of gray cast iron brake discs. The research concludes that under low-temperature wear conditions, the graphite in the gray cast iron structure can enter into the interface between the friction pair, have a lubricating effect on the wear surface, and reduce the friction coefficient and wear loss of the gray cast iron material. As the graphite content in the gray cast iron structure increases, the lubrication and protection effect of the graphite increases, and the wear failure of gray cast iron is mainly caused by plastic deformation-induced fatigue peeling. Under high-temperature wear conditions, an oxide layer gradually forms on the wear surface. With the increase of experiment temperature, the thickness of the oxide layer increases on the wear surface. When the oxide layer formed on the wear surface reaches a certain level of thickness, the internal expansion stress of the oxide layer increases considerably, causing the oxide layer to peel off and increase the roughness of the wear surface, friction coefficient, and wear loss. Additionally, with the increase of the graphite content in the gray cast iron structure, the surface is more prone to oxidation, leading to the increase of friction coefficient and wear loss. The wear failure of gray cast iron is mainly caused by oxidation layer peeling.