Microstructure and Mechanical Properties of Welded Additively Manufactured Stainless Steels SS316L

Microstructure and mechanical properties of additively manufactured SS316L has been investigated. The samples produced by selective electron beam melting machine were then subjected to gas tungsten arc welding. Various examinations were performed including metallography and microscopy, hardness testing, and tensile testing coupled with digital image correlation software. Strain distribution was clearly evident on the samples during tensile testing with necking taking place at the heat affected zone on both sides of the weldments. From tensile testing, it was clear that the ductility and strengths of the samples were equal to those of conventionally produced samples such as rolled sheet. Hardness testing indicated the uniform distribution across the base metal and the weldments. Scanning electron microscopy identified the presence of Cr and Mo-rich precipitates on the grain boundaries, while the fracture surface was entirely covered with dimples (microvoid coalescence) indicating a ductile fracture mode.