Wire-based directed energy deposition (DED-wire) used as additive manufacturing technology for industrial Inconel 718 tools for robotic friction stir welding (R-FSW)

The Inconel 718 nickel-base superalloy (IN718) is a high-strength and highly corrosion-resistant material used in several industrial applications. Its high mechanical and chemical properties make this material a focus of interest for additive manufacturing because IN718 is expensive, and a heat treatment post-manufacturing is typically needed. This greatly increases costs and production time, with a loss of material due to machining of the material blocks that can be avoided with additive manufacturing by providing material only where needed. For the Robotic Friction Stir Welding (R-FSW), a tool with high performance is demanded. In this work, IN718 tools for the R-FSW process have been additively manufactured with optimized parameters under high manufacturing speed conditions and with the advantages of using metal wire. As-built and heat-treated conditions heat have been microstructural and mechanically analyzed. Finally, different tool designs of the same IN718 DED-wire manufactured material have been tested in several friction stir welds, analyzing their behavior and the relation with the successful welds. Optimal thermal conditions and design parameters for IN718 FSW tools were established.