Corrosion behavior of additively manufactured AISI 316L stainless steel under atmospheric conditions

Abstract

This study investigated the corrosion behavior of AISI 316L produced by direct energy deposition (DED). Microstructural and chemical analysis showed a homogeneous distribution of Si and Si-Mn inclusions of 0.5-1 µm and the Cr and Mo enrichment within interdendritic areas. Scanning Kelvin probe analysis of additively manufactured stainless steel highlighted a regular "striped-like" surface potential feature with a potential gradient of 30 mV for a mean value of 0.320 ± 0.017 V versus standard hydrogen electrode. It can be related to the presence of the residual stress in the oxide film and the complex thermal history due to the fabrication process. A cyclic corrosion test simulating atmospheric conditions revealed the same corrosion properties for stainless steel fabricated by DED compared to cold rolled one. Various surface preparations of 316L were also exposed for corrosion tests. It was found that the "as-received" and "brushed" surfaces exhibited poorer corrosion resistance due to the presence of an as-build defective layer. However, prior passivation of brushed surface, machining, or mechanical grinding down to P1200 improve significantly the corrosion resistance.

Experimental and Analytical Investigation of the Re-Melting Effect in the Manufacturing of 316L by Direct Energy Deposition (DED) Method

“…Most of these studies have tried to establish a link between the fabrication parameters of selective laser melting (SLM), laser-engineered mesh forming (LENS), and DED and the mechanical properties of building materials [7,10]. In some studies, it has been reported that the microstructure regularity and the increase in the time interval between successive layers positively affect the mechanical properties due to an increase in the cooling rate [6,12]. However, very little work has been conducted on the effects of the re-melting process during the production of 316L material through the DED method [13][14][15].…”

Mechanism of surface corrosion resistance of 304 stainless steel processed by nanosecond laser pulses

“…Stainless steel is widely used in aerospace, automobile, mobile communication, medical equipment, and architecture due to its excellent formability, corrosion resistance, compatibility, and toughness. [1][2][3][4][5] However, when stainless steel is exposed to a corrosive environment for a long time, its performance can be significantly reduced. [6,7] Because problems of pickling pollutants, uneven passivation regions, and serious environmental pollution have been discovered in the pickling passivation of stainless steel, this process does not meet the process requirements of green cleaning.…”