FIGURE 3.

The principles of different welding methods are shown above. Arc welding at the example of SMAW is depicted in (A). In (B) a schematic of local cavity laser welding is depicted, showing the nozzle and shielding gas. On the right the different welding modes are illustrated: The conduction mode with a shallow weld pool at the top and the penetration mode with a black keyhole at the bottom. (C) Shows the process of friction stir welding, with the required forces depicted in blue. A close up of the tool shows the non-consumable pin and shoulder.