Influence of pulsed TIG welding process parameters on the mechanical characteristics of AA5083 with AA6082 weldments

Abstract

Aluminium alloys have been widely accepted in manufacturing lightweight materials with high strength. Therefore, welding aluminium alloys is essential in industrial applications to attain complex shapes. In the present work, AA5083 and AA6082 dissimilar alloys were welded using pulsed tungsten inert gas (PTIG) welding since PTIG reduces welding defects more than TIG welding. But to get better mechanical strength on the weld joints, PTIG welding process parameters must be optimized. During PTIG welding, peak current, pulse frequency, and welding speed were chosen as the input parameters, and ultimate tensile strength (UTS) and microhardness were measured as output responses in the current investigation. The UTS of the welded AA5083-AA6082 alloys was predicted using an empirical relationship. For the design of experimental trials, a three-variable, five-stage central composite design is adopted. The findings indicate that the welding speed impacts tensile strength the most, followed by the peak current and the pulse frequency has the least impact. Therefore, the peak current of 197 A, pulse frequency of 4.9 Hz, and welding speed of 181 mm min−1 was identified as the optimal welding parameters to weld AA5083 and AA6082 alloys with high UTS values. The hardness analysis on the optimized welded samples showed that the lowest hardness values of 40 to 50 Hv0.5 and the highest value of 90 to 100 Hv0.5 were observed on the HAZ of the AA6082 side of the weldment.