Effect of notch on low cycle fatigue behaviour of 316 LN stainless steel

In the present investigation, effect of notch on low cycle fatigue behaviour of 316 LN stainless steel have been assessed by carrying out low cycle fatigue (LCF) tests on smooth and notched specimens of steel. The LCF experiments were carried out at strain amplitudes ranging from +/- 0.3 to +/- 1.0 % and at a strain rate of 3 x 10(-3) s(-1) at room temperature. The material exhibited prolonged softening after a few initial cycles of hardening followed by saturation and final failure. The gradual softening following initial hardening was not observed for the highest strain amplitude of 1 %. Fatigue life was found to decrease in presence of notch. The extent of decrease in fatigue life was higher for relatively sharper notch. Fatigue life of the notched specimens has been estimated based on the local plastic strain using finite element analysis and Neuber's rule. The FE analysis approach was found to underestimate the fatigue life in presence of notch, whereas Neuber's rule overestimated the fatigue life.