Laser Direct Energy Deposition Welding of AISI 316 Stainless Steel Sheets

The present paper assesses the applicability of laser powder direct energy deposition for welding of thin stainless steel sheets. Considering the rapid development of laser cladding and relatively wide range of equipment available in modern industrial settings, this technology can also be applied to laser welding, where the procedure is performed with a filler material comprising blown powder. To this end, an exhaustive experimental campaign has been carried out with the aim of evaluating the influence of the main process parameters, including laser power and powder feed rate, on the resulting weld bead characteristics. Two joint configurations have also been considered to assess the best solution in terms of both chamfer shape and sheet positioning. Butt and lap joints were prepared, with 30° and 45° V-groove configurations tested and characterized in the former case. In order to assess the resulting weld quality, metallographic analyses were carried out to measure the main morphological parameters of the weld beads, including width, penetration depth and reinforcement, and to evaluate the possible presence of defects such as pores, cracks or lack of melting. Tensile tests were also carried out with the purpose of characterizing the overall mechanical performance of the joints. These tests demonstrated good overall process feasibility and highlighted the fact that lap joints and 30° V-groove butt joints were the best configurations in terms of both weld bead quality and fused zone morphology.