Seam welds quality in AA6060 alloy

In the first part of the work an experiment, specifically designed to highlight different seam welds joining conditions on the AA6060 alloy, is discussed and analyzed. A modular die, generating an I shape profile with a longitudinal weld in the middle section, was used to extrude the profiles at different pre-heating temperatures and production rates. Different welding chamber shapes were also used. The extracted specimens were tensile tested: ultimate tensile strength and elongation at fracture were recorded. Sequentially, FEM simulations of the experimental conditions were realized by means of thermo-mechanical simulations with the code Deform 3D and the local welding parameters were linked to tensile tests results by means of welding criteria. In the second part of the work, FEM simulations and welding criteria were applied to the extrusion of a round shape tube of 80mm diameter and 0.9mm thick. Two different die geometries were used in order to evaluate the effect of the legs shape on product’s mechanical proprieties. Finally, experimental trials and tensile tests have been realized on specimens extracted from the extruded profiles in order to validate FEM simulations predictions.