Development of Flux-Core Electrodes for Welding Large Titanium Structures

Arc Welding of titanium has always been a challenging engineering problem, requiring shielding from atmospheric contamination (e.g., oxygen and nitrogen) until the metal is below approximately 400oC. Small titanium weldments are typically welded in inert gas chambers. However chambers are impractical for welding large structures. Instead, auxiliary shielding devices (e.g., trail- and back-side shields) must be provided, which result in significantly higher costs, and require a high level of skill. Thus, developing a method of producing high-quality titanium welds, without the need for auxiliary shielding devices, would provide a significant cost benefit for fabricating large titanium structures. One potential method of eliminating the need for auxiliary shielding devices is to develop a flux-cored consumable to shield the weld metal with a blanket of slag. WeldQC, Inc. proposes to evaluate the feasibility of developing flux-cored consumables for welding titanium using the GTAW and FCAW processes. The proposed effort will address the needs of the SBIR Topic No. N04-124 "Joining Methodologies for Titanium Alloys" by developing a cost-effective method of welding large-scale titanium weldments, which have acceptable levels of interstitial elements and mechanical properties. WeldQC, Inc. has formed a team with Colorado School of Mines (CSM), The Stoody Company, and Ingalls Shipbuilding.