Transferred arc oscillates in an alternating magnetic field imposed perpendicularly to the arc. The amplitude of oscillatory arc motion can be varied easily by adjusting the magnetic flux density. The heat flux distribution can be controlled by changing the wave form of the magnetic field. Using such magnetically driven arc, the authors developed a novel heat treatment system which consisted of a device for the generation of DC arc, that for the formation of various types of magnetic field, a mechanism for travelling the work piece and water circuit for quenching the heated material. Heat treatments for the steel material of S45C were performed using different wave forms of the magnetic field. The magnetically driven arc was able to produce various patterns of drawing on the steel surface such as a single belt with broad width, two parallel straight lines with different spacing, a series of diamond form and two parallel wavy lines. It was confirmed that Vickers hardness increased more than three times after the heat treatment.
