Wire arc additive manufacturing of invar parts: Bead geometry and melt pool monitoring

[Display omitted] •A meltpool monitoring strategy based on the analysis of its symmetry is presented.•Deposition conditions have been optimized to ensure correct bead geometry.•Wall symmetry, measured by macrographic analysis, shows a mean value of 0.998. Additive manufacturing processes using the direct energy deposition method, one of which is the Wire Arc Additive Manufacturing (WAAM), have gained much attention in the scientific community over the last decade. The application of WAAM to Invar, an iron-nickel and manganese alloy, with a low amount of chromium carbon, also called FeNi36 or Nivarox has been the subject of various reports due to its challenging nature. This paper utilizes and unifies research material previously investigated in this technology, taking a new approach based on the study of symmetrical phenomena that guarantee the quality of the process. On the one hand, a method of analysis of the geometry of the manufactured wall is presented based on its symmetrical quality which guarantees the maximum use of material and, on the other hand, the monitoring of the symmetry of the melting pool utilizing thermography techniques.