Comparative Analysis by Finite Element Method of Welding Paths in Aluminium Alloys T-Joints

Abstract

In recent decades, due to their great advantages, the aluminium alloys have been more and more used in the shipbuilding industry, particularly in the construction of yacht superstructures. Nevertheless, a significant disadvantage of aluminium alloys subjected to welding is their high deformation tendency, which represents an important drawback that needs additional remedial measures. In this study, a finite element analysis was performed, in order to investigate and optimize the design of welding paths used to carry out AA 5083 aluminium alloy T-joints of 6mm thick sheets by Metal Inert Gas (MIG) welding. The research methodology was focused on three case studies, in order to determine and comparatively analyse the Heat Affected Zone extend and the level of stress and displacement. In the first case, the welding beads were successively deposited, following the same welding direction. In the second case, the seams were successively welded, but the welding directions on one side and on the other side of the joint were opposite. In the third case, the seams were simultaneously welded, on both sides of the joint, the welding directions being opposite, as in the previous case study. Based on the research results, it was found that the larger Heat Affected Zone (HAZ) was identified in the third case study, while the total displacement was 25-30% lower, in comparison with the results obtained in the first two case studies. This phenomenon can be explained by the high amount of heat developed simultaneously by two electric arcs and transferred, by conduction, to the base materials. Due to the joining technology applied, that consisted in welding simultaneously on the both sides of the joint, an adequate balance of stress and strain was achieved, determining a lower total displacement.