Effects of plasma-MIG hybrid welding parameters on performance and hot cracking susceptibility of 5083 Al alloy butt-joint welds

A novel plasma-MIG hybrid welding process, which combines the advantages of plasma arc and MIG welding, can improve the welding efficiency of aluminum alloy thick plates and reduce defects. The effects of plasma-MIG hybrid welding parameters on the penetration capability, tensile strength, weld bead microstructure, and hot cracking susceptibility of 5083 aluminum alloy 6-mm-thick butt-joint specimens were investigated. In this study, hybrid welding parameters such as plasma arc current, distance between plasma arc torch and base metal, torch travel speed, and plasma arc argon flow rate were selected. The results demonstrated that specimens produced with a higher plasma arc welding current at 163 A could improve the penetration capability but reduced the hot cracking susceptibility of specimens. The specimens produced at a higher torch travel speed of 340 mm/min had better tensile strength and lower hot cracking susceptibility. Using a lower plasma arc argon flow rate at 3.7 L/min during the plasma-MIG hybrid welding process not only improve penetration capability, but also increase the tensile strength of the 5083 aluminum alloy weld to 265.2 MPa.