It should be taken into account that the HFW pipe is a type of ERW pipe.
The high frequency welded steel pipe (HFW) is that ERW pipe produced with a welding current frequency equal to or greater than 70 kHZ. Through resistance to high frequency current welding, heat is generated in the contact objects, whereby the object surface is heated to the plastic state, then, with or without forging, to achieve a combination of steels. HFW is a solid resistance thermal energy. The high frequency current that passes through the metallic conductor will produce two peculiar effects, the skin effect and the proximity effect. The HFW process uses the skin effect to concentrate on the surface of the steel object and uses proximity effects to control the position and power of the high frequency electric current flow path. Since the speed is very high, the edge of the contacted plate can be heated and melted in a short time, then extruded through the coupling process.
Advantages of the HFW pipe
In the welding process, HFW steel pipes do not need to add filler metal. Therefore, it has high welding speed and high production efficiency. HFW pipe is widely used in the fields of oil and gas transportation, oil well pipelines, building structures and various types of mechanical pipes. However, the quality of HFW steel pipes is affected by many factors, such as raw material and process. And production quality control becomes difficult. Therefore, the performance and welding process must be continuously improved.