High-frequency induction welding is one of the methods in which high-frequency alternating current (H.F) is used as a resistance current to melt the edges of the sheet. In induction welding machines, a high frequency magnetic field is alternately induced to the outer surface by a welding ring (coil) and a very strong induced current in the tube excites the free electrons of the tube. Stimulation of electrons at the edges of the sheet generates very intense heat and melts the edges of the sheet. The melted edges are brought together at a point and placed inside each other by molds and the welding operation is performed completely. The most common use of induction welding machines is in the manufacture and production of steel pipes.
