Shot peening intensity effect on bending fatigue strength of S235, S355 and P460 structural steels

Abstract

In this study, the effect of shot peening intensity of the structural steel specimens on the bending fatigue strength was investigated. Three structural steels S235JRG2, S355J2+N, P460NH were shot-peened with three levels of intensity. The results of fatigue tests were compared with non-peening processed samples. S-N curves in fatigue were determined in cyclic bending fatigue. The novel attempt to evaluate the bending fatigue, which relies on the 3D optical profiler measurement of the side-area of fractures, was proposed. All investigated steels present ferritic-pearlitic structure. Moreover, due to the peening process, refinement of the grains size was observed. Also, fractures were analysed with the 3D profiler. In the presented results of research, the highest level of peening gave the greater increase in fatigue life. For all types of investigated steels, shot-peening gave superior results of fatigue bending performance compared with unpeened specimens.