Induction welding
Induction welding is a form of welding that uses electromagnetic inductions to heat the workpiece. The welding machine contains an induction coil, which is charged with electric current of radio frequency. This creates a high frequency electromagnetic field, which acts either on electric conductive or on a ferromagnetic billet.
In the electrically conductive billet, the main thermal effect is resistive heating, which is due to induced currents, called eddy currents. In a ferromagnetic preform, heating is mainly caused by hysteresis, since the electromagnetic field repeatedly distorts the magnetic regions of the ferromagnetic material.
In practice, most materials are subjected to a combination of these two effects.