Metal Additive Manufacturing Conference - MAMC 2021

Stainless steel (SS) of type 316L is one of the go-to materials for metal additive manufacturing (AM), due to its good weldability. As-printed 316L SS made by AM has unconventionally good mechanical properties exhibiting both high strength and high ductility. However, the corrosion resistance is inadequate, and not on par with conventional 316L. Our research team has demonstrated proof of concept for the lab-scale manufacturing of modified 316L with excellent corrosion resistance combined with superior mechanical properties as compared to “conventional” AM. The method entails modification of the feedstock powder, while the MAM method remains unchanged. The microstructure of the modified 316L is comparable to that of 316L manufactured by L-PBF. Elongated austenite grains with the mechanically beneficial internal cellular substructure were obtained. The powder modification resulted in a Vickers hardness increase of about 40 HV0.1 in the as-built condition. The modification also improved the corrosion resistance, as measured by weight loss after immersion in 5.6% FeCl3 solution for 10 days.
The method has also proven useful for strengthening of duplex stainless steels, and is also expected to be applicable for achieving strength and corrosion resistance in ferritic stainless steels, and for enhancing the AM processability of martensitic stainless steels. The present contribution will also showcase different aspects and applications of the technology.