Effect of heat treatment on selective laser melted steel parts

Selective Laser Sintering (SLS), has become one of the most popular technique in the layer manufacturing processes because of the ability to build complex geometries models with a wide range of materials. Driven by the need to process nearly full dense objects, with mechanical properties comparable to those of bulk materials and by the desire to avoid long post processing cycles, Selective Laser Melting (SLM) has been developed. In SLM complete melting of powder occurs,unlike SLS which is mainly characterised by liquid phase sintering or partial melting. The aim of this work was to evaluate performances of SLM parts built with powders of 18 Ni Marage 300 steel after a tempering treatment. The optimal process parameters (in terms of laser power and scanning strategy) has been determined in order to get parts of almost full density. A full DOE plan was used with a three level of energy density.