A critical review of corrosion characteristics of additively manufactured stainless steels

Abstract

Additive manufacturing (AM) is associated with a sequence of rapid heating and cooling cycles along with large temperature gradients, developing complex thermal histories which have direct influence on resultant microstructures. Such a dynamic and far-from-equilibrium process leads to distinct microstructural features that are expected to cause changes in the corrosion characteristics of AM stainless steels. Currently such changes are not well understood, consequently inconsistencies and disagreements are frequently found in the literature on the corrosion behaviour of AM stainless steels. This paper performs a critical review of corrosion characteristics of AM stainless steels by assessing the effects of their unique microstructural features on corrosion behaviour, with particular focus on new corrosion phenomena and selected critical forms of localised corrosion including pitting corrosion, erosion-corrosion, intergranular corrosion, fatigue corrosion, and stress corrosion cracking. Discussion on the mechanisms of these corrosion phenomena and behaviour, as well as major influencing factors, are undertaken, leading to recommendations and suggestions for future development of AM stainless steels for various corrosive conditions.

Pitting Corrosion in 316L Stainless Steel Fabricated by Laser Powder Bed Fusion Additive Manufacturing: A Review and Perspective

“…The specific microstructures 18 and numerous defects 4,5 encountered in LPBF 316L SS require classification beyond just an incremental variation of the conventional, well-annealed 316L SS (referred to hereafter as CWA 316L SS). 42,43 For example, the Mn-rich sulfides that play a major role in pitting initiation in CWA 316L SS [44][45][46] are not present in the LPBF material due to the rapid solidification and cooling that prevent this phase from forming. 23,47,48 Thus, pit nucleation operates under a different dominant mechanism.…”

Materials challenges in hydrogen-fuelled gas turbines

“…The authors point out the necessity of focusing on the optimisation of fabrication parameters and establishing a correspondence between key structural features and corrosion resistance. Laleh et al [134] reviewed the corrosion behaviour of austenitic, precipitation-hardened, and duplex stainless steels processed by AM in comparison with the conventionally produced counterparts. The review addressed the corrosion resistance in acidic and NaCl solutions at room temperature.…”

Effect of Thermal Treatment on Corrosion Behavior of AISI 316L Stainless Steel Manufactured by Laser Powder Bed Fusion

“…Inclusions typically found in L-PBF AISI 316L stainless steel are fine Si- and Mn-rich oxide nanoparticles or Cr-containing silicate inclusions of a nanometric size [ 10 , 13 , 16 , 17 ]. MnS inclusions are usually not found in L-PBF stainless steel, although these inclusions have been reported in some cases after post-processing thermal treatment [ 18 , 19 , 20 ]. Residual stresses are unavoidable in materials produced by additive manufacturing [ 1 , 21 , 22 ].…”

“…The corrosion performance of additively manufactured AISI 316L stainless steel has been targeted by many researchers focusing on the effect of process parameters and the main metallurgical factors, including porosity, inclusions, alloying element segregation and residual stresses [ 4 , 19 ]. It is generally observed that additively manufactured AISI 316L stainless steel presents higher corrosion resistance than the conventionally produced counterpart in the wrought condition [ 18 , 27 , 28 , 29 , 30 , 31 , 32 ].…”