Fatigue strength and life assessment of L-PBF 316L stainless steel showing process and corrosion related defects

Abstract

The present work focuses on the modelling of the fatigue behaviour of a 316L produced by laser powder bed fusion containing various defect populations : Lacks of fusion, corrosion pits and one electric discharge machined hemispherical defect. As shown in previous experimental studies, the crack leading up to failure systematically initiated on a single surface defect. The nature and morphology of the critical defect did not show any influence on the fatigue strength, and only its size seemed to matter. To take into account the critical defect size, models based on linear elastic fracture mechanics were implemented and identified. A modified Paris propagation law was used to model the short crack regime. This approach was used to predict S–N curve domains based on critical defects size range.