Corrosion behaviour of 316L stainless steel manufactured by selective laser melting

Abstract

This work investigates the electrochemical behaviour of an AISI 316L stainless steel produced by selective laser melting (SLM) and compares its behaviour with that of wrought stainless steel with similar chemical composition. The SLM stainless steel specimens are tested in the as‐produced condition without stress relief or recrystallization heat treatments. The electrochemical tests are carried out in two electrolytes: 3.5 wt% NaCl solution with neutral pH and with pH of 1.8. At the macroscale, the microstructure of the SLM specimens is determined by the laser scanning pattern and displays an overlapping network of melt pools. At the microscale, the SLM specimens exhibit a cellular/columnar dendritic structure with submicrometric cell size. Electrochemical measurements highlight a more extended passive range for SLM stainless steel in both neutral and acid electrolytes indicating higher protective properties of the oxide film on SLM specimens. In contrast to the wrought material, the refined microstructure of the SLM specimens promotes a very shallow morphology of attack without deep penetration in the bulk.

Corrosion of Additively Manufactured Stainless Steels—Process, Structure, Performance: A Review

“…Others have reported selective attack of Cr, Mo depleted cell interiors within pits after anodic polarization in neutral chloride solution. 19,54 Nakao and Nishimoto showed similar preferential attack of primary austenite-solidifying substructure for LSM 904L SS (UNS N08904) in ferric chloride. [55][56] Furthermore, they demonstrated that the pitting resistance (pitting potential and critical pitting temperature) of this same material in ferric chloride solution increased with decreasing levels of microsegregation of Ni and Cr in the solidification substructure, Figure 5.…”

“…Distribution of corrosion studies in terms of stainless steel alloy, process, and environment. [2][3][4][5][6][7]10,[18][19]27,29,37,[47][48][49][50][51][53][54]57,[68][69]76,[91][92][101][102][103][104][105]109,116,129,134,137,144,[146][147][148][149]153,178,[185][186][187][188][189][190][191][192][193][194]…”

“…The elevated oxygen content of the powder feedstock (from surface oxides and inclusions) combined with the build atmosphere can result in up to 10 times higher oxygen content of the AM consolidated material relative to conventionally processed alloys. 18,20,54,80 Most of the oxygen in the consolidated material manifests itself in the oxide inclusions, discussed in Nonmetallic Inclusions, section 3.4. 20,80 Build quality is also dependent on powder storage, handling, and recycling procedures.…”

Corrosion Fatigue Characteristics of 316L Stainless Steel Fabricated by Laser Powder Bed Fusion

“…Although the microstructure and mechanical properties of alloys made from AM techniques have been studied extensively, there is a lack of deeper understanding regarding their corrosion related properties. The key microscopic characteristics in AM that affect the corrosion properties remain controversial [3][4][5][6][7][8][9][10]. The findings of the limited relevant studies regarding the effects of various types of microstructures/defects are briefly discussed in the following.…”

Microstructure and corrosion behaviors of FeCrNiBSiMox stainless steel fabricated by laser melting deposition

“…The reason why stainless steel has good corrosion resistance is that the formation of a dense passivation film on the surface of the stainless steel during the corrosion process can prevent the corrosion from continuing. Moreover, the formation of the passivation film depends on the environmental factors where the material is to be placed and the chemical composition of the alloy material . Some researchers have found that the addition of Mo in stainless steel can accelerate the formation of passivation film and reduce the corrosion current density of the active region in neutral halide solutions .…”