Optimization of Tig Welding Parameters for Hardness and Study the Effect on Microstructure of Titanium Alloy

Titanium alloys are used extensively in aerospace applications such as components in aero-engines and space shuttles, mainly due to their superior strength to weight ratio.The need to weld the alloy for certain engine components can expose the alloy locally to non-optimum thermal cycles and it is therefore of important to study the effect of process parameters on weld quality.To improve the welding quality of Titanium (Ti) plate an automated TIG welding system has been developed, by which welding speed can be control during welding process.Welding of Titanium has been performed in 9 phases with different set of parameters using L9 orthogonal array.Effect of welding current, welding speed and gas flow rate on hardness of welded portion has been investigated.Taguchi Orthogonal array, signal to noise (S/N) ratio and analysis of variance (ANOVA) are employed to investigate the welding characteristics of titanium, optimize the welding parameters and calculate contribution of each parameter.Optical microscopic analysis has been done on the weld zone to evaluate the effect of welding parameters on welding quality.