A Comprehensive Review on the Effect of Thermal Post Processing on DMLS Processed SS316L Components

Abstract

SS316L is an austenite-grade steel material offering a better strength-to-ductility ratio, higher corrosion resistance, and biocompatibility. In DMLS products, residual stresses are inevitable because of the thermal gradient involved in the process and the porosity that results from process limitations. As a result of these defects, the strength of the product is reduced and the quality of the product is compromised. The primary objective of this article is to offer an in-depth analysis of different heat treatment methods that are employed to achieve superior properties in products manufactured through DMLS processing. Thermal processing techniques include Hot Isostatic Pressing, Solution Heat Treatment, T6 heat treatment, Direct Aging Treatment, etc. Using thermal post-processing techniques, 99.99% of the porosity is eliminated, corrosion resistance is significantly increased, and mechanical properties are enhanced. This study examines the need for thermal post-processing, the methodology employed, and the property enhancements achieved by DMLS products. There are many factors affecting thermal post-processing, however, efforts have been made to review the details regarding thermal post-processing applied to SS316L material processed with direct metal laser sintering. Moreover, the specific methods for post-processing can be determined based on the product's intended application.