Effect of wire feeding temperature on titanium grade 5 pipes welding using gas tungsten arc welding

In industrial applications where both high corrosion resistance and mechanical strength are required, titanium-based materials such as Titanium Grade 5 (Ti-6Al-4V) stand out as a preferred choice. Due to its low density, high specific strength, and excellent resistance to oxidation, this alloy plays a critical role in the aerospace, defense, chemical, and biomedical industries. However, the welding of such materials demands special control measures and equipment due to their high sensitivity to atmospheric conditions. Although conventional Tungsten Inert Gas (TIG) welding provides high joint quality, its low deposition rate limits productivity, particularly in thick-section components. In this study, in accordance with ASTM B862-14, which governs the fabrication of welded titanium and titanium alloy pipes, the effects of hot wire feeding during the semi-automatic TIG welding of Titanium Grade 5 pipes with a wall thickness of 12.7 mm were investigated. The use of thick-walled pipes aimed to better analyze the influence of the hot wire feeding process. Within the scope of the study, filler wire was electrically preheated by applying currents of 0 A, 75 A, and 150 A before entering the weld pool. Welding parameters were kept as constant as possible, and only the current through the filler wire was varied to isolate the effects of hot wire feeding. The resulting welds were evaluated in terms of tensile and yield strength, penetration depth, hardness distribution, and impact toughness. The results demonstrated that hot wire feeding increased welding efficiency, improved penetration, and positively influenced the mechanical and metallurgical properties. Thus, this method presents an effective solution for automated welding of titanium alloys.