Materials Selection for Camshafts

Abstract

Surface hardening, a process involving a wide variety of techniques, is used to improve the wear resistance of parts without affecting the softer, harder interior of the part. This combination of hard surface and resistance to breakage on impact is beneficial in parts such as a cam or ring gear that must have a very hard surface to resist wear and a hard interior to resist the resulting impact. There are two distinctly different approaches to the various methods for surface hardening: a) Thermochemical diffusion methods that change the chemical composition of the surface with hardener species such as carbon, nitrogen and boron, b) Applied energy or thermal methods that do not change the chemical composition of the surface, but rather improve the properties by changing the surface metallurgy; that is, they produce a hard quenched surface without additional alloy types. In this study, materials selection for camshafts is reviewed and candidates from cast irons and steels are criticized and classical and computer based methods are employed for the best selection.