Fatigue Strength of Tufftrided Steel

A Study on the Strengthening Mechanism-S15CK Smooth Specimen

Abstract

A study on the strengthening mechanism for fatigue strength of tufftrided S15CK smooth specimens was carried out. The results obtained are as follows;
(1) The fatigue limit of the tufftrided S15CK smooth specimen is about 41kg/mm², which equals twice the fatigue limit of the untufftrided one. The fatigue limit of the tufftrided specimen can be estimated fairly well from the hardness distribution after fatigued and the residual stress distribution.
(2) As the factors which cause the fatigue strength elevation of tufftrided steel, the effects of low temperature quenching, compressive residual stress and supersaturated nitrogen are considered. The ratio of elevation in fatigue limit due to each effect amounts to 10, 15, and 50%, respectively.
(3) The compound layer has no effect on the fatigue limit of tufftrided steel.