Welding and additive manufacturing of titanium and its alloys by the gmaw process – Arc instability characteristics

Abstract

The GMAW welding process faces significant challenges when applied in the welding and deposition of titanium and its alloys. Challenges include electric arc instability, unstable metal transfer, splash generation, and the formation of irregular weld beads. Given the existing difficulties there is a constant effort of science to understand and solve them, especially in the context of Arc and Wire Additive Manufacturing, where the GMAW process is highly advantageous due to its high productivity. This work aims to present the evolution of knowledge related to the operational difficulties faced when using the GMAW process for welding and deposition of titanium and its alloys, in addition to highlighting the techniques developed to overcome these challenges. The scientific literature indicates that operational difficulties have their origin in the cathodic emission process. GMAW process applied to titanium is characterized by the emergence of a high-luminosity jet that protrudes frontally. This jet originates from a cathode point, which often changes position, resulting in the formation of irregular weld beads. The phenomenon also makes it difficult to fully incorporate the metal drop into the melting pool, leading to the generation of splashes. Although there are reports that this jet is formed due to thermionic cathodic emission, there are hypotheses of other reasons.

DOI:https://doi.org/10.56238/uniknowindevolp-080