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TIG welding has wide area of application in various industries like automobile, aerospace and
marine, etc. In TIG welding, welding parameters and filler materials play a vital role in creating a
strong welded joint. This research work was focused on investigation of effect of process
parameters and filler materials on TIG welding of AA 5052-T0 and AA 7075-T0. In the present
study, three TIG welding parameters, current, gas flow rate and filler rod diameter were changed
up to three levels and their effects on tensile strength, flexural strength (face/root), micro-hardness,
and microstructure were investigated. Two different filler materials, ER 4043 and ER 5356 were
utilized in this study. Experiments were conducted on a 1.5 mm thick sheet of AA 5052 and AA
7075 and were designed according to Taguchi method. Moreover, for optimization techniques like
S/N ratio, ANOVA analysis and regression analysis were also utilized. For ER 4043 samples,
maximum tensile strength, flexural strength (face), flexural strength (root) and micro-hardness
obtained were 193.2 MPa, 382.3 MPa, 271 MPa and 77.1 HV respectively. Similarly, for ER 5356
sample maximum tensile strength, flexural strength (face), flexural strength (root) and microhardness obtained were 196.4 MPa, 481.9 MPa, 187 MPa and 88.6 HV respectively. It was found
that current was the most influential parameter followed by filler rod diameter. ER 5356 showed
better mechanical properties but it was more prone to hot cracking. Optimized responses were
obtained at current 70A, gas flow rate 11 L/min and filler rod diameter 1.6 mm with ER 5356 filler
rod diameter. Model confirmatory test showed less than 5% error between predicted and
experimental values. Microstructural analysis also showed presence of intermetallic compounds
like Al-Si, Mg2Si and Al3Mg2 in welded samples of ER 4043 and ER 5356.