EN10219 Steel Pipe DN1200

EFW: Single Plate Forming, Arc Welding Fusion

EFW (Electric Fusion Welded) is quite different. It uses single steel plates as raw materials, which are first pressed into U-shapes and then O-shapes by a hydraulic press to form a pipe blank, and then the welds are filled and fused by arc welding (such as submerged arc welding). Unlike ERW, EFW requires filling welding wire and flux during the welding process, and the weld is formed by the fusion of the base metal and the filler metal.

Huayang's EFW production line is equipped with a 4000-ton hydraulic forming machine and a double-wire submerged arc welding system, which can process steel plates with a thickness of up to 40mm and produce large-diameter pipes with DN up to 1200mm. In the 2023 Sinopec high-pressure gathering and transportation project, 1.5 million tons of DN800 EFW pipes produced by Huayang successfully withstood the test of 1.8MPa working pressure, and the weld qualification rate reached 100%.

The biggest difference between EFW and ERW in forming is "discontinuity". Due to the need to replace steel plates and adjust molds frequently, the production speed of EFW is only 0.3-0.5 meters per minute, which is far lower than that of ERW. However, its advantage lies in the adaptability to thick plates and large diameters, which ERW cannot match.