| Abstract: |
As additive manufacturing (AM) becomes more widely used for production work, the need for welding solutions of these structures will increase. The potentially extreme complex geometries of AM parts means that the precision of autogenous, semi-automatic, CNC welding methods will be particularly useful for joining. Specifically low heat input processes, such as electron beam welding, will be useful for minimizing distortion. The microstructure of AM produced parts differs greatly from those produced by traditional methods, such as castings, wrought parts, or rolled sheet. AM microstructures are often striated, can be less dense, and the small grain sizes cause variations in mechanical properties, including hardness, strength, and ductility. The welding characteristics may also follow suite with deviations from the wrought materials of the same chemistry. The mechanical properties of wrought tensile bars were compared to the properties of AM tensile bars in both the electron beam welded and un-welded state. Results will be presented that show with proper parameter selection one common AM metal, 17-4 PH stainless steel, can be welded to yield similar mechanical properties to that of a wrought part. In addition, some examples of AM parts that have been successfully electron beam welded at PTR Enfields contract welding department will be presented to show the potential for both the weldability and the type of sophisticated assemblies possible that are additively manufactured and electron beam welded.
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