Transferability of mechanical-technical parameters to the fatigue strength and mean stress sensitivity of additively manufactured 1.4828 austenitic stainless-steel components

In contrast to traditional manufacturing techniques, the PBF-LB/M process offers unique design benefits, including the capability to create thin-walled geometries, internal channels, and intricately structured lattice structures that cannot be produced by subtractive processes. The localized laser energy input, layer-wise consolidation, and exceptionally rapid cooling rates produce refined microstructures and distinctive residual stress states that are specific to this technique and significantly affect the resultant mechanical behaviour. In addition to the static parameters, fatigue strength also represents a crucial parameter. Classic calculation guidelines use the tensile strength of the material and the geometry of the component as input parameters for the design of operational strength. However, the transferability of the calculation methods to additively manufactured materials has hardly been investigated. This study analyses the applicability of the FKM (Forschungskuratorium Maschinenbau e.V.) guideline to the fatigue assessment of additively manufactured 1.4828 austenitic stainless steel (AISI 309 or X15CrNiSi20-12) regarding parameters like tensile-compressive alternating strength and mean stress sensitivity. For this purpose, quasi-static and load-controlled fatigue tests were performed on as-built specimens (part conditions right after the printing process) under two load ratios: fully reversed loading (R = − 1) and tensile mean stress (R = 0.1). The correlation between the experimental data and the FKM calculations shows a good agreement, indicating that the guideline provides a reasonable estimation of the fatigue behaviour even for as-built AM components.