Wear resistant components for IC engines - esp. ferritic chromium stainless steel piston ring used in cast iron cylinder with carbonitrided bore

摘要

The two components are in sliding contact with each other, one consisting of a cast iron cylinder with its bore subjected to low temp. gas carbonitriding to form a nitride layer with outer zone and a diffusion layer. Nitride layer has min. Vickers hardness 400 and min. thickness(t) 3 mu m, where the nitriding density is min. 2.5% for the thickness of 3/mu m. The second component is a steel piston ring with surface VH of min. 200 and consisting of a matrix contg. complex carbides of (FeCr)7C3 and/or (FeCr)23C6; and the running surface of the ring may be provided with a nitriding layer. Low rate of wear between engine cylinder and the piston ring is provided.