Friction Stir Welding Across Joining Direction

Friction stir welding is a better alternative for fusion welding of aluminum and magnesium alloys. This technique is being explored for various new materials and welding configurations in last two decades. But the developments concentrated mostly on longitudinal welding in which welding is performed in parallel direction to the joint. Due to this, welding the components with smaller widths that are smaller than shoulder diameter of welding tool is not possible. In this study, it was experimented and proved for using the technique in perpendicular to joining direction for welding smaller width components. This development enables to use friction stir welding to weld short lengths in the order of few mm. Friction stir welding of magnesium alloy AE42 and aluminum alloy AA2024 of 4 mm thick, 50 mm width and 100 mm length were carried out for the developmental work. Welding was done to join two such plates to join them at 50 mm side in multiple passes to obtain 200 mm long components after welding. Penetration of welding was maintained as 95% of the thickness. Joint strength was evaluated and found 75-80% of parent metal for both the alloys. The distance between the passes in the multi pass welding was main parameter studied in this work. Resultant joint strength, microstructure, hardness and HAZ size were analyzed and compared in detail.