Submerged Arc Welding (SAW) is a process in which an arc is developed between a consumable bare wire electrode and the workpiece. A pile of granular flux is deposited on the work surface ahead of the electrode. The arc forms within the flux, thereby melting a portion of the flux blanket that shields the molten weldpool and adjacent base metal. The granular flux gives protection from atmospheric contamination. The method is generally mechanized and is employed to achieve very high deposition rates, e.g., for heavy section material. SAW is generally characterized by high heat input, high penetration, and, thus, dilution of the molten pool by base metal. As with the Shielded metal arc welding (SMAW) process, submerged arc welding is applied principally to stainless steels and nickel alloys. Flux metal reactions are usually complex, and welding conditions have been closely controlled to obtain consistent weld metal composition. The effects of the high heat input of SAW are normally considered before selecting this process. 1
This is a very instructive video by Arc Energy Resources on the submerged arc welding (SAW) process.