Effect of weld geometry on fatigue performance of 6061-T6 aluminum GMAW: part 1. Butt joint

Abstract

The use of aluminum in automobile bodies has increased in recent years due to its various advantages. However, the research conducted on the fatigue performance of aluminum arc welding is limited. This study conducts 6061-T6 aluminum GMAW experiments for the various weld geometries to determine their effect on the fatigue performance. These weld geometries, which include full penetration, partial penetration, welding with misalignment, different toe angles, and double butt joints, are obtained by controlling the welding conditions. Full penetration presents the best fatigue performance, and the toe angle exhibits a relatively minimal effect on fatigue performance. Misalignment causes a large reduction in the fatigue performance. In the partial penetration and double butt joint case, the non-welded part, where the stress is concentrated, is located at the bottom. Therefore, these two cases present a relatively lower fatigue performance. In the automobile production process, the use of a backing plate is limited; therefore, controlling the penetration depth significantly improves the fatigue performance, despite the difficulty in obtaining the desired penetration depth. Double butt joints present the advantage of penetration depth control; therefore, a double butt joint can be considered as an appropriate alternative solution for full penetration despite the additional cost involved in the double butt joint preparation.