Experimental evaluation of mechanical strength parameters of additively manufactured food-grade AISI 316 stainless steel

Direct metal laser sintering (DMLS) has become one of the most widely used methods for the additive manufacturing of metallic machine parts and tools. It allows the usage of all available metals and metallic alloys, enabling the production of parts with significant geometric complexity, which other technologies cannot produce. Many engineers, however, express concerns regarding the mechanical strength and reliability of items produced via DMLS. This article presents the results from an experimental evaluation of the basic strength parameters of samples of AISI 316 stainless steel, which were additively produced by means of selective laser sintering. Possible redistribution of the key alloying elements and changes in the phase state, which could result from the laser's thermal action and compromise the steel's corrosion resistance, have also been investigated using SEM and EDS. The experimental results revealed that the 3D printed parts show lower tensile strength by 13 % and lower modulus of elasticity by 57 %. The residual elongation after breaking and cross-contraction is also lower. The additively manufactured parts were also revealed to be porous, which could be seen as a disadvantage in the food processing industry.