Differences Between ERW and EFW Steel Pipe

ERW is the abbreviation of electric resistance welding.
The welding method of ERW pipe and submerged arc welded pipe is significantly different. The pressure welding method without filler metal is adopted. The weld is not filled with other components, and the skin effect and the proximity effect of the high frequency current are used to instantaneously heat the edge of the plate. At the soldering temperature, the weld of the forged structure is extruded by a squeeze roll. High-quality steel pipes require heat treatment on the weld line or off-line to refine the microstructure of the weld zone. The weld of the high-quality ERW welded pipe can reach the same level of toughness as the base metal, which cannot be achieved by the submerged arc welding process.

EFW is the abbreviation of electric fusion welding.
One of submerged arc welding (SAW)-electric welding (EFW) is a process in which metal is heated by one or several consumable electrodes and a workpiece to heat the metal, and the arc is used to make the metal and fill. The material is fully melted and does not require pressurization. The part of the filling metal is all from the electrode.
Melt Gas Shielded Welding (GMAW) – A type of electrofusion welding (EFW) that is similar to submerged arc welding, but its protection comes from inert gases and works better.
Spiral welding – this is also a type of submerged arc welding with a spiral weld.

Extended information:
Welding is achieved by the following three ways:

1. Fusion welding – heating the workpiece to be joined to partially melt it to form a molten pool. After the molten pool is cooled and solidified, it is joined. If necessary, it can be added to the filler. It is suitable for welding of various metals and alloys. pressure.

2. Pressure welding – welding process must apply pressure to the weldment, belonging to the processing of various metal materials and some metal materials.

3. Brazing – The metal material with lower melting point than the base material is used as the brazing material, the base material is wetted by the liquid brazing material, the joint gap is filled, and the base material is mutually diffused to realize the link weldment. Suitable for welding of various materials, also suitable for welding of different metals or different materials.

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