Effect of welding parameters on penetration depth in FB-TIG welding of 5083 aluminum alloy

In the present study, effect of current, welding speed and preheat temperature during FB-TIG welding of AA5083 aluminum alloy was studied. Using the Taguchi method, 9 different tests were designed to investigate the effect of welding parameters on the penetration depth. Consistent with predictions, increasing the current and preheat temperature, and reducing the welding speed led to an increase in penetration depth. The maximum penetration depth of 8.02 mm was achieved at the current of 220 A, welding speed of 120 mm/min, and the preheat temperature of 100 °C. Taguchi analysis showed that increasing the welding current and preheat temperature had a more significant effect than the welding speed. Microstructural analysis indicated that the weld metal is fine-grained, along with coarse-grain in the HAZ of all samples. Many pores were observed in the samples with high welding speed and high welding current in the fusion zone. The sample with the highest heat input had the highest penetration depth. This sample had the highest elongation, equal to 69% of the base metal. Moreover, microhardness test demonstrated that the hardness of this sample dropped sharply from 70 Vickers to 58 Vickers in the HAZ.