A Study on the Notch Effect on the Low Cycle Fatigue of Metals in Creep-Fatigue Interacting Conditions at Elevated Temperature

Abstract

Frequency and hold-time effects on fatigue lives of cylindrical notched specimens of SUS 316 stainless steel were studied at 600° C in air. From the tests, the following conclusions were obtained: Neuber’s rule, as used in the ASME N-47 Code, predicts very conservatively the life of notched specimens in tests without a hold-time. But it gives a nonconservative estimate for the reduction in the life of the material by the introduction of a hold-time. An empirical formula of a “frequency-elastic stress concentration factor modified equation” was obtained by analysing the experimental data. It predicts accurately the life of the notched specimen tested at different frequencies.