submergedarc

Submerged arc welding (SAW) is a welding process that uses a continuously fed consumable electrode and a granular flux to shield the weld. The arc is produced between the electrode and the workpiece, while the flux is supplied from a hopper and forms a molten slag that completely covers the weld pool, protecting it from air and moisture. The process can be performed automatically or semi-automatically, often on long seams or thick sections.

Equipment consists of a wire feeder, a welding head, a flux hopper, a drive mechanism, and a power source capable of high current. The electrode wire is fed through a contact tube to the arc, the flux melts and forms a slag layer; the slag must be removed after welding. SAW typically uses direct current with either positive or negative polarity or alternating current, depending on material and thickness.

SAW offers high deposition rates, deep penetration, and smooth, uniform weld beads with excellent mechanical properties. It has high productivity but is generally limited to flat or horizontal positions and requires a prepared joint; it also requires a backing or support surface for certain welds. The flux composition determines deoxidation, alloying, and slag characteristics.

Common applications include shipbuilding, pressure vessels, heavy steel structures, and pipelines where long, straight welds on thick sections are required. Safety considerations include fumes from flux and proper ventilation, and adherence to relevant welding standards and PPE.