Fatigue Behavior of Exhaust Valve Alloys

This paper reviews the fatigue properties of internal combustion engine exhaust valve alloys. Examples of typical exhaust valve fatigue failures are shown along with an explanation of the factors leading to these failures. The results of laboratory engine tests designed to duplicate underhead fatigue failures and evaluate the effect of valve design are discussed. The elevated temperature fatigue strength of common exhaust valve alloys in plain air and corrosive environments is presented along with a method to determine fatigue crack initiation and propagation rates. The results of scanning electron microscope studies correlate well with the experimentally determined crack growth rates.