Electron Beam Welding of Inconel 718

This paper presents a study of Electron Beam Welding (EBW) of rolled Inconel 718 (IN718) plates. The experiment utilized nine different heat inputs at three different levels of welding speed and beam current. The weld quality was characterized and ranked based on weld geometry, microhardness and mechanical properties. Fusion area and weld penetration depth were found to be proportional to the heat input. Microhardness measurement showed a wider and softer weld zone at the beam entrance. Voids, found at weld bottoms when welding at the highest beam power of 3250 watt and scanning speed exceeding 0.78 m/min, can be removed by a suitable machining process. All samples but one had tensile strength exceeding the specification for rolled 1N718 (837 MPa); ductility of welded specimens also met the specification (57%) when welding with heat input less than 225 J/mm. At low heat inputs, the welded samples fractured outside of the weld zone and indicated their exceptional weld strength. The samples welded at higher heat inputs cracked and fractured at the weld. These results provide a benchmark for comparison with future study on EBW of selective laser melted IN718. (c) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/) Peer review under the responsibility of the scientific committee of NAMRI/SME.