Weldability aspects in the design and fabrication of aluminium structures subjected to fatigue loads. Part 2. Weldability of aluminium alloys using advanced MIG and TIG techniques: Effect of the weld bead geometrical factors on the fatigue behaviour of the welded joint

Aluminium alloys are increasingly being used as welded construction materials in order to achieve more lightweight structures. However, the specific properties of the various aluminium alloys are relatively little known, and the experience gained from steel welding cannot, as such, be applied to aluminium. This complicates successful design and fabrication and has an adverse effect on the productivity and quality of welding as well as the structural strength of the welds. The Laboratory of Production Engineering and the Metals Laboratory of the Technical Research Centre of Finland (VTT) have participated in a Nordic research project entitled "New methods for joining of aluminium". The results from Finnish work of this project will be presented in a report to be published in two parts. This Part 2 of the report examines welding procedures suitable for high-strength 5xxx (AIMg) and 6xxx (AlSiMg) series aluminium alloys using advanced MIG and TIG techniques and evaluates the weldability of these alloys, as well as the importance of the shape of the weld bead for fatigue strength of the welded joint.