Evaluation of Microstructure and Porosity for 3D Printed Stainless Steel

In this study, the microstructure and porosity for stainless steel 17–4 PH produced by selective laser melting (SLM) based on different build orientations were characterised and schematically generated. As manufacturing companies are developing more techniques to meet new industrial needs, additive manufacturing for metals is highlighted due to its ability to generate complex metallic parts specifically the SLM method. However, the commercialisation of generating stainless steel for performance parts is largely underdeveloped. The specimen in this study was made by melting 17–4 PH powders using the selective laser melting method of powder bed fusion. The powder distribution analysis using ImageJ and microstructural properties were generated using JMatPro software and verified using the XRD test. The phases austenite and martensite were further investigated using an optical microscope in specific mapping methods that separates the top and side views. Porosity is observed to be in three main geometries, crescent and triangular for process-driven porosities and spherical for gas-driven porosities. Since mechanical properties are driven by microstructure profile observed, these findings generate the foundation understanding to comprehend microstructural behaviours of SLM stainless steel 17–4 PH.