It should be noted that HFW pipe is a type of ERW pipe.

High frequency welding (HFW) is a solid resistance heat energy. Through high-frequency current welding resistance, the heat generated in the contact objects, so the objected surface are heated to the plastic state, then with or without forging to achieve a combination of steels.

The high frequency current pass through the metal conductor, will produce two peculiar effects, skin effect and proximity effect. And HFW process is to use the skin effect to concentrated on steel object surface, use proximity effects to control the position and the power of the high-frequency electric current flow path. Since the speed is very high, the contacted plate edge could be heated and melted in shore time, then extruded through docking process.The productivity of HFW steel pipe is high, the welding speed can reach 30m/min, and the welding current frequency is equal to or greater than 70 kHZ. It is mainly used to make pipes with welded longitudinal seams or spiral seams. The welded pipe is welded by high-frequency welding technology and is mainly used for the transportation of pressurized fluids such as water, oil, and natural gas.
                                                                                             
Sizes:
Out Diameter:12"-24"
Wall Thickness: 1.65-20mm
Length: 3m-12m

Standard: ASTM 5L, ASTM A53, ASTMA178, ASTM A500/501, ASTM A691, ASTM A252, ASTM A672, EN 10217

Advantage of HFW pipe
In the welding process, HFW steel pipes do not need to add filling meta. So it has fast welding speed and high efficiency in production. HFW pipe is widely used in the fields of oil and gas transportation, oil well pipeline, building structure and various kinds of mechanical pipe. However, HFW steel pipe quality is affected by many factors, such as raw material and process. And the production quality control become difficult. So the yield and welding process still need to be improved continuously.