Behaviour of nionikral-70 in low-cycle fatigue

Abstract

Experimental research on the behaviour of high-strength low-alloy steel ( HSLA)exposed to low-cycle fatigue (LCF) with controlled and fully reversible strain (Delta epsilon/2 = const, R epsilon =epsilon(min)/epsilon(max) = -1) has been analysed. LCF tests are performed on a series of smooth bar shaped specimens, 11 x 11 x 95 mm, parent metal (PM), welded joint (WJ) and simulated heat affected zone (SHAZ) of steel Nionikral 70 (NN-70) with semi-amplitude of controlled strain, Delta epsilon/2 = 0.40- 0.80. The results of the experimental investigation have given us important information on the understanding of fatigue behaviour of steel NN-70 and its welded joints. In this work the results of static and dynamic-, that is monotonous and fatigue behaviour of the material, are compared, which is a practical contribution to the assessment of the behaviour of PM and WJ of steel NN-70 exposed to effects of low cycle fatigue, i.e. monotonous and fatigue behaviour of the material.