Fatigue strength of PBF-LB/M and wrought 316L stainless steel: effect of
post treatment and cyclic mean stress
Abstract
Additive manufacturing (AM) enables the cost-effective production of
complex components, many of which are traditionally manufactured using
costly production steps among other processes. One widely applied AM
process is Laser-based Powder Bed Fusion of Metals (PBF-LB/M); however,
internal pores and rough surfaces are typically inevitable with
PBF-LB/M, reducing fatigue and corrosion resistance compared to
traditional processes involving turning and milling. Additionally, large
defects often occur near to or just at the surfaces. Thus, this study
investigates the effect of hybrid additive and subtractive manufacturing
on the fatigue strength of AISI 316L. For this purpose, different post
treatment routes are compared with wrought material. Additionally,
computer tomography is used to determine the necessary machining depth
of the surface layer. In this study, heat-treatment and machining are
both found to significantly increase fatigue strength. Finally, cyclic
mean stresses affect wrought and AM specimens differently.