Optimization of the weld characteristics of plasma-arc welded titanium alloy joints: an experimental study

Titanium alloys especially Ti6Al4V have wide commercial applications in various sectors of aerospace manufacturing industries owing to their excellent physical, mechanical, and thermal characteristics. Titanium alloys are mostly welded by conventional gas tungsten arc welding process which gives compromisingly higher productivity. There are welding technologies like plasma arc welding that provide high arc energy density results in good-quality welds with higher productivity. In this present investigation, the efforts were put to study and optimize the important welding variables, such as weld current, speed, plasma gas flow rate, and constricted arc length. These parameters govern the most desired characteristics of weld bead such as weld bead width, complete penetration, fusion zone area, and prior β grain size. Optimum solutions were found through desirability-based multi-response optimization by response surface methodology. Microstructural features and mechanical properties were evaluated for the joints welded using the optimum process parameters and found that characteristics are well within the desired criteria.