Grain refinement through arc manipulation techniques in Al–Cu alloy GTA welds

Effect of three arc manipulation processes pulsed current welding, magnetic arc oscillation and the simultaneous application of pulsed current and arc oscillation, on the weld metal grain structure and tensile properties of the welds were investigated. Initial studies were conducted on autogenous welds made on 3.5 mm thick 2219-T6 plates, to identify and optimize, welding parameters resulting in fine equiaxed grains in the weld metal. Welds were made on 8.5 mm thick 2219-T87 plates using the optimized parameters and tested for tensile properties. All three techniques resulted in fine equiaxed grains in weld metals and optimum parameters were suggested based on the extent of refinement. Fine-grained weld metals exhibited better yield and ultimate tensile strengths and significant improvement in percent elongation. The reasons for the same were explained with the help of TEM and EPMA studies.