ERW VS EFW Pipe

What is ERW Pipe?

Electric resistance welding (ERW) is a welding method that uses the skin effect and proximity effect of high-frequency current to instantly heat the welding edge to the welding temperature, and forms a forged structural weld by extrusion. Due to pressure welding, no welding material is required, and the material of the weld is the same as that of the base metal. It should be noted that high-quality steel pipes generally require on-line or off-line heat treatment of the weld to refine the structure of the weld zone. The processed weld can achieve the same level of toughness as the base metal. Unable to implement the connection process.

ERW steel pipes can meet low pressure and high pressure requirements. In recent years, with the development of ERW technology, more and more ERW steel pipes are used in oil and gas fields, automobile industry, etc.

What is EFW Pipe?

Electric fusion welding (EFW) is a process in which metal is heated between the workpieces through one or several consumable electrodes, and the metal is combined between the molten welding material and the base metal. Since the molten filler material is used for connection, there is no need to pressurize the workpiece, and the filler metal part comes entirely from the welding rod. In addition, submerged arc welding (SAW)and molten gas shielded welding (GMAW) also belongs to electric fusion welding (EFW).

At the aspect of applications, EFW steel pipes can be used in thetextile,oil and gas, pharmaceutical and fluid pipe industry.

As far as the production of steel pipes is concerned, the production process of electric welded pipes is relatively simple, with high production efficiency and low equipment investment. Since no welding consumables are used, the welding strength is stronger than EFW, but the overall strength is still lower than that of seamless pipes. With the rapid development of continuous rolling production of high-quality strip steel and the advancement of welding and inspection technology, the quality of welds has been continuously improved, and the varieties and specifications of welded steel pipes have continued to increase, replacing seamless steel pipes and more fields.