Preliminary investigation on hybrid welding of selective laser molten parts

In this paper the innovative arc-fiber laser welding process (hybrid welding) was investigated on steel parts built by the Selective Laser Melting (SLM) process. SLM is probably the most rapidly growing technique in Additive Manufacturing (AM) technologies. This success results mainly from the possibility to create metal parts with complex shape, intrinsic engineered features and mechanical properties comparable with those of components produced with traditional processes. One of the limitation of the process is represented by the small dimensions that can be processed; this is mainly due to the high residual stresses generated during the process. A preliminary study was performed on the possibility of welding SLM parts. The choice of the hybrid arc-fiber laser welding was justified by the possibility of this process to avoid air inclusions and fill gaps along the seam due to the relevant roughness of SLM parts. The hybrid joints were characterized in terms of micro-hardness, microstructure and shape of the transverse cross section. Comparisons between wrought, sintered and dissimilar welds were performed