Corrosion Resistance Measurement of 316L Stainless Steel Manufactured by Selective Laser Melting

Abstract

Selective laser melting (SLM) technology is ushering in a new era of advanced industrial production of metal components. It is of great importance to understand the relationship between the surface features and electrochemical properties of manufactured parts. This work studied the influence of surface orientation on the corrosion resistance of 316L stainless-steel (SS) components manufactured with SLM. The corrosion resistance of the samples was measured using linear polarization resistance (LPR) and electromechanical noise (EN) techniques under three different environments, H2O, 3.5 wt.% NaCl, and 20% H2OSO4,, analyzing the horizontal (XY) and vertical (XZ) planes. The microstructure and morphology of the samples were obtained by optical (OM) and scanning electron microscopy (SEM). The obtained microstructure showed the grains growing up from the fusion line to the melt pool center and, via SEM-EDS, the presence of irregular and spherical pores was observed. The highest corrosion rate was identified in the H2SO4 solution in the XZ plane with 2.4 × 10−2 mm/year and the XY plane with 1.31 × 10−3 mm/year. The EN technique along with the skewness factor were used to determine the type of corrosion that the material developed. Localized corrosion was observed in the electrolyte, for the XY and XZ planes (−1.65 and −0.012 skewness factors, respectively), attacking mainly the subgrains of the microstructure and, in some cases, the pores, caused by Cl ions. and solutions presented a uniform corrosion mechanism for the two observed orientations. The morphology identified by SEM was correlated with the results obtained from the electrochemical techniques.

A Comparative Study of Corrosion AA6061 and AlSi10Mg Alloys Produced by Extruded and Additive Manufacturing

“…The AlSi10Mg (Al-A.M) alloy matrix had a dendritic microstructure. The microstructure evolved due to the SLM manufacture, where the eutectic phase of silicon was observed and some pores of various sizes [ 16 , 39 , 40 ].…”

“…%), Figure 19 c, the spectra EDS indicated the presence of oxygen and silicon in the darker zone, marked with a blue box (average 20.36 and 28.60 wt. %), respectively [ 16 ].…”

“…Having a rough surface can degrade both electrochemical performance and material life under dynamic loads. Furthermore, corrosion resistance is also related to the natural ability of the material to form a passive and adherent layer under regular atmospheric conditions [ 15 , 16 ].…”

Stress Corrosion Cracking of 316L Stainless Steel Additively Manufactured with Sinter-Based Material Extrusion

“…The resulting sintered microstructure has been reported to have a weak crystallographic texture, relatively large equiaxed grains, and populated with twin boundaries, pores, and oxide inclusions [5][6][7][8][9]. These characteristics diverge from the typical columnar grains found in other AM technologies where the heat follows the dissipation route, such as laser-engineered net shaping (LENS) [10,11], electron beam additive manufacturing (EBAM) [12,13], and laser-based powder bed fusion (LPBF) [14,15].…”