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I. Applications of submerged arc welding Submerged arc welding has many advantages and is one of the most commonly used automatic arc welding methods in modern industrial manufacturing. It is primarily used for welding various steel plate structures. Weldable carbon structural steel, low-alloy high-strength steel, low-alloy structural steel, stainless steel, heat-resistant steel, and composite steel, etc. Furthermore, surfacing with submerged arc welding using heat-resistant and corrosion-resistant alloys, or welding nickel-based alloys and copper alloys, is also quite ideal. Submerged arc welding can be applied in industries such as shipbuilding, boilers, chemical containers, bridges, lifting machinery, and metallurgical machinery. II. Welding materials and their selection for submerged arc welding: The welding materials used in submerged arc welding include wire and flux, which correspond to the core and coating of electrodes. In submerged arc welding, the wire and flux are directly involved in the metallurgical reactions that take place during welding; therefore, their chemical composition and physical properties affect the welding process. These factors, in turn, influence the chemical composition, microstructure, and properties of the weld metal as a result of the welding process. Choosing the right welding wire and flux and using them in a proper combination is an important aspect of submerged arc welding technology. The selection of submerged arc welding wires and fluxes will be discussed in detail in subsequent articles; no further explanation is given here. It should be noted that, in order to meet the requirements of welding materials of different thicknesses, wires of the same grade can be manufactured in various diameters. The common diameters for submerged arc welding wires are 2 mm, 3 mm, 4 mm, 5 mm, and 6 mm. When using these wires, it is necessary to remove any oil or rust from their surface to avoid affecting the quality of the weld. Some welding wires have a thin layer of copper coated on their surface, which prevents the wire from rusting and ensures more reliable electrical conductivity between the nozzle and the wire, thereby improving the stability of the arc. In recent years, the use of sintered fluxes has become increasingly widespread. Compared with molten fluxes, sintered fluxes have the following advantages: Sintered fluxes are high-quality, efficient, energy-saving, and environmentally friendly fluxes. This weld produces no smoke, no odor, and no spatter during welding. The manufacturing process results in minimal environmental pollution, low energy consumption, and efficient use of raw materials, in line with **industry development policies. Sintered flux has a low bulk density, a thin slag skin, low flux consumption, and thus lower welding production costs. The alkalinity value of sintered fluxes can be adjusted over a wide range, allowing them to be used for welding materials with poor weldability. They can meet the physical and chemical requirements for welds that have very low hydrogen content, high strength, high toughness, and high purity. Currently, sintered fluxes are widely used in the welding of high-alloy steel structures such as high-strength steel and stainless steel, including pressure vessels for nuclear reactors and hydrogenation reactors. Various deoxidizers and alloying agents can be added to sintered fluxes, allowing for easy adjustment of the chemical composition of the weld metal; this gives it unique advantages in the submerged arc surfacing process technology. The sintered flux is easy to prepare scientifically, and its welding process exhibits strong adaptability. It can be used for welding in various conditions such as thin sheets, fillet welds, ultra-large scale applications, high-speed welding, multi-wire welding, applications requiring porosity resistance, narrow gaps, and deep grooves. It features excellent slag removal properties and good weld formation. Most sintered flux products are in the form of spherical particles, which facilitates the transportation and recovery of the flux during the welding process.