WHAT IS HIGH FREQUENCY RESISTANCE WELDING 

HFRW can generate resistance heat through connecting welding parts by 10-500KHz high frequency current that heat up the outer surface of welding parts to become fusion and plastic state.Meanwhile two side of metal joint can be fused together by HFRW welding that is Solid State Resistance Welding technology.
High Frequency Resistance welding(HFRW) is invented in the earlier year 1950 later it rapidly used for industrial production.Nowadays HFRW is mainly used for mechnical and pipe &tube and profile under high-level-automation field.
The material of welded parts can be steel or non-ferrous metal, tube diameter range from 6-1420mm,wall thickness from 0.15 to 20mm.Normally small dia tube adopt longitudinal welding seam.Large pipe mostly adopt spiral welding seam.

Advantage of HF welding：
1.High welding speed：
As the current can be highly concentrated in the welding area, heating speed is extremely fast, the general high frequency welding speed up to 150-200m/min.
2.Small heat affected area：
Because of the high welding speed and the self-cooling effect of the weldment, the heat affected area of the high frequency welding is small and hardly oxidized, so that the welding seam get good structure and performance.
3.No need clean before welding：
As high-frequency current has very high voltage,it can breakover the weld surface oxide film, also through the flash process, extrusion,it can effectively remove the oxide of connector and other impurities. Inert gas is only used for protect metal welding such as titanium,etc which has very fast reaction with oxygen and nitrogen, only need to use inert gas for protection