Investigation on wear behaviors of high-vanadium high-speed steel compared with high-chromium cast iron under rolling contact condition

The wear property of high-vanadium high-speed steel (HVHSS), compared with high-chromium cast iron, was studied using self-mate rolling wear testing apparatus under rolling contact condition, and the microstructures and failure behaviors were analyzed by electron microscopes. Results show that the relative wear resistance of HVHSS is four times higher than that of high-chromium cast iron. The initiation and propagation of cracks mainly depend on the substructure and morphology of carbides, which determine wear resistance of materials. It is difficult for cracks in HVHSS to initiate inside VC because of the reinforcement of MC-type nano-particles carbides inside VC. The cracks mainly initiate at the VC/matrix interface, and propagate along surface of VC, resulting in crack blunting. Whereas, the cracks in high-chromium cast iron mainly initiate inside M7C3 because of blocking of dislocation inside M7C3, resulting in dense crack-initiation sites inside M7C3. After propagating a short distance, those dense cracks join each other to form through main crack, resulting in rapid failure of high-chromium cast iron.