It is well-known that the enormous increase in fatigue strength of case hardened steel is due to the high compressive residual stress in the material and to the doubled hardness caused by heat treatment, and that the effect of the residual stress on the endurance limit can be accounted for by taking it as the mean stress.In this paper the fatigue test results which were obtained of the carburized and induction hardened steel, have been re-examined from the viewpoint of crack propagation process. It appears that the fatigue strength of case hardened steel can be regarded as resistance against fatigue crack propagation in the specimen having minute flaw, because, in highly hardened material, the micro inclusions and metallurgical discontinuity can be taken as the origins of fatigue cracks.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.