A study on the fatigue characteristic and fatigue limit prediction of induction surface hardened Cr-Mo alloy steel

Practically, induction surface hardening is widely used to enhance the local strength of structure. In this study, Fatigue limit and its S-N characteristic for basemetal and induction hardened specimen of SCM440 is studied experimentally. To consider the effect of notch, fatigue tests are performed varying the notch diameter(d=0.2, 0.3, 0.5 and 1/0(mm)). Two step S-N curve is plotted in case of smooth specimen of induction hardened specimen. And Fractography of fractured surface is also considered. To perform quantitative evaluation of fatigue limit, root Area parameter is applied to induction surface hardened notched steel under consideration of presence of residual stress.