The welding methods of ERW pipes and submerged arc welded pipes are significantly different. The filler-free metal pressure welding method is used. The weld seam is not filled with other components. It relies on the skin effect and proximity effect of high-frequency current to instantly heat the plate edge to the welding temperature. Extruded by silver, the forged structure of the weld is formed. High-quality steel pipes require online or offline heat treatment of the welds to refine the structure of the weld area. The welds of high-quality ERW welded pipes can reach the same toughness level as the base material, which cannot be achieved by buried fox welding processes.
Submerged arc welding (SAW) is a type of electrofusion welding (EFW). It is a process that combines metals by heating the metal between one or more consumable electrodes and the workpiece. The arc causes the metal to bond with the filler. The welding material is completely melted, no pressure is required, and the filler metal comes entirely from the electrode.
Gas fusion welding (GMAW)-Electric fusion welding (EFW), this process is similar to submerged fox welding, but its protection comes from inert gas, and the effect will be better.
