Additive manufacturing of 304 stainless steel integrated component by hybrid WAAM and LDED

There is an increasingly urgent need for the integrated fabricating of large components with locally fine structures for additive manufacturing. Combining highly efficient low-cost Metal Inert Gas-Wire Arc Additive Manufacturing (MIG-WAAM) with finely formed and high-performing Laser Directed Energy Deposition (LDED) is an effective manufacturing method. In this paper, the hybrid fabricating process research of MIG-WAAM and LDED was carried out with 304 austenitic stainless steel as the fabricating material. The mechanical properties and microstructure transition modes of different process in different directions were analyzed. The results show that the hybrid manufacturing technology combines the advantages of WAAM (high efficiency) and LDED (precision). Well-fabricated 304 stainless steel samples were obtained. The phase consists of γ-austenitic matrix phase, δ-ferrite, and Si oxide-containing spherical phase. The LDED process obtain a finer and denser structure than WAAM, resulting in better strength and microhardness. The tensile strength follows the pattern of gradually decreasing from scanning direction, transverse direction to building direction. The hybrid manufacturing bond strength is greater than the tensile strength of the WAAM region. It is shown that the hybrid WAAM-LDED process can produce fine structures and improve the surface flatness of WAAM structures.