A mathematical model to predict impact toughness of pulsed-current gas tungsten arc-welded titanium alloy

Titanium (Ti-6Al-4V) alloy has gathered wide acceptance in the fabrication of lightweight structures requiring a high strength-to-weight ratio, such as in the applications of transportable bridge girders, military vehicles, road tankers, and space vehicles. The preferred welding process for welding titanium alloy is frequently gas tungsten arc welding (GTA) due to its comparatively easier applicability and better economy. In the case of single-pass gas tungsten arc welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous-current process. In this investigation, an attempt has been made to develop a mathematical model to predict impact toughness of pulsed-current gas tungsten arc-welded titanium alloy weldments. Four factors, five level, central composite, rotatable design matrix is used to optimize the required number of experiments. A mathematical model has been developed with the response surface method (RSM). The adequacy of the model has been checked using ANOVA technique. By using the developed mathematical model, impact toughness of the joints can be predicted with 99% confidence level.