Fatigue life rationalization of laser shock peened SAF 2205 with different swept direction

Abstract

This work studies the effects of two laser swept directions during laser shock peening treatments (LSP), parallel and perpendicular to the rolling direction, in duplex stainless steel SAF 2205. In order to compare the changes induced by both treatments; roughness, microhardness, residual stress, phases proportion, dislocation structure and chemical composition were analyzed in the near-surface of treated and untreated samples. This paper attempts to explain, through the preceding analysis, the fatigue performance of SAF 2205 untreated and treated with two laser swept directions. The results reveal that the phaseś morphology of cold rolled SAF 2205 plays a crucial role on the effects caused by LSP. Higher microhardness and compressive residual stresses were found when the laser advancing directions is perpendicular to the rolling direction leading to a longer fatigue life. This fact is rationalized considering the interaction of the swept direction with the phases’ morphology of the steel.