Observations on the influence of process and corrosion related defects on the fatigue strength of 316L stainless steel manufactured by Laser Powder Bed Fusion (L-PBF)

This paper focuses on the relationship between the fatigue performance and the presence of process or corrosion related defects for a 316L stainless steel manufactured by Laser Powder Bed Fusion . The fatigue responses of three batches (polished, pre-corroded and with an Electric Discharge Machined (EDM) defect) were investigated. A good correlation between Murakami’s a r e a parameter and the fatigue strength was observed. Defect morphology does not seem to be an important factor for crack initiation as ellipsoidal corrosion pits , hemispherical EDM defects and flat lacks of fusion, although very different in terms of shape, are just as harmful at equivalent sizes. • Original fatigue tests on a L-PBF 316L stainless steel were carried out. • Different types of defects (pores, corrosion pits, artificial defects) were studied. • The fatigue strength sensitivity to defect size was characterized. • The effect of defect morphology did not seem relevant to explain the large scatter. • The HCF behaviour of the L-PBF 316L was superior to the wrought one for small defects.