Joining technologies, and among them, welding processes, play a key role in engineering and are essential for the manufacture of components, since many of them have welded joints. The capacity to create mechanically resistant joints, whose properties do not degrade with time, is critical in many applications and must be taken into account in the design, production and inspection stages. These joints can be found both in large constructions (buildings, transport, fluid pipes, etc.) and in smaller ones (electronic devices, small components,...). That is why joining technologies are identified as key enabling technologies for the development of innovative and sustainable manufacturing processes.
Within this context, electric arc welding processes hold a relevant historical position. Intensely developed after World War I, they have reached our times as mature, but constantly evolving technologies, proving, throughout, their ability to adapt to industry’s changing demands. Nowadays, the high quality of arc welded joints together with the high productivity of these processes and a somewhat lower cost than other joining technologies, mean that the position of arc welding in the market is extremely competitive.
The energy source used in arc welding processes to melt the base material is an electric arc. This arc is established between an electrode, which may or may not be consumable, and the two parts of the base metal to be joined together. MIG/MAG (Metal Inert or Active Gas) is the most noteworthy process that applies consumable electrodes, while TIG (Tungsten Inert Gas) and PAW (Plasma Arc Welding) (see Figure 1) are the processes without consumable electrodes which are mostly employed. As outstanding innovative processes in the market, we can highlight variants of the traditional MIG/MAG process with controlled heat input, and greater stability of the electric arc, such as the Cold Metal Transfer (CMT) process, developed by the Austrian manufacturer, Fronius, or variants of the traditional TIG process, but with greater productivity, such as the ArcTIG, TIGger or TIGSpeed processes, developed by different welding equipment manufacturers.