Selective laser melting (SLM) is a promising approach for a future manufacturing technology as it allows the fabrication of arbitrary structures from a powder base material. Whereas, for materials like steel the technology is already well established, its application for refractory metals is still in the early stages. In order to gain a deeper understanding of the SLM process and its material specific characteristics, in this contribution a 3D thermo-fluiddynamical multi-phase simulation model is presented and applied for an analysis of SLM of molybdenum and steel. The model shows the influence of process parameters on the process dynamics and the processing result as well as the material specific differences in SLM. The presented results show good correlation to experimental data.