One of the welding process that are commonly used in the construction industry is the Submerged Arc Welding (or what they call it SAW). his process is fully automised. Sample pictures are shown below.
SAW requires a continuously fed consumable solid electrode. The molten weld and the arc zone are protected from atmospheric contamination by being “submerged” under a blanket of granular fusible flux. When molten, the flux becomes conductive, and provides a current path between the electrode and the work. This thick layer of flux completely covers the molten metal thus preventing spatter and sparks as well as suppressing the intense ultraviolet radiation and fumes.