Corrosion performance of additively manufactured stainless steel parts: A review

Abstract

The application of additively manufactured (AM) stainless steel (SS) parts is rapidly emerging in a broad spectrum of industries. Laser powder bed fusion (LPBF) and direct laser deposition (DLD) are the main AM methods to fabricate a vast range of SSs like 316 L, AISI 420, 17-4 PH, 304 L, and AISI 4135. This article focuses on the corrosion performance of additively manufactured stainless steel parts made by LPBF and DLD. The passive film formation mechanisms and the corrosion performance of LPBF/DLD AM SS parts are discussed in comparison to their conventionally made counterparts. Microstructural features like porosity, inclusions, residual stress, surface roughness, elemental segregation, phases, and grain size distribution are elaborated thoroughly from the corrosion point of view, closely linked with the AM processing parameters. Generally, process parameters play an important role in the corrosion properties of AM parts by impacting the microstructural features. Assuming a proper set of parameters for the printing process, the overall corrosion performance of AM SS is better than its conventional counterparts. However, there are still controversies around some important aspects such as passive film structure, the nature of residual stress, post heat treatment processes, and grain size distribution and their impact on corrosion performance, which emphasizes the need for future studies in this area.