Influence of Different Notch Insertion Methods on the Fatigue Behavior of Metastable Cr‐Ni‐Cu‐N and AISI 316L Austenitic Stainless Steels

ABSTRACT The fatigue behavior of a metastable austenitic Cr‐Ni‐Cu‐N steel and an austenitic AISI 316L steel was investigated with a focus on the effect of mechanically machined and formed notches, taking into account hardness and residual stress measurements. The highest fatigue strengths were achieved with the metastable austenitic steel and formed notches. Positive effects resulted from strain hardening, martensitic transformation, and residual compressive stress states. In addition, the formed notches showed a longer remaining lifetime after damage initiation. The mechanically machined notches of the metastable austenitic steel yielded pronounced martensitic transformation and very high residual compressive stresses in direct vicinity of the surface, which resulted in an improvement in the high‐cycle fatigue regime. A lifetime calculation was applied that takes the residual stresses of the formed notches into account.