PURPOSE: To improve the cutting workability by supplying DC current between an electric power supplying electrode and a position to be cut to generate arc, overlapping AC current to this DC current and reducing the magnetization of the DC magnetized part with the AC magnetization.
CONSTITUTION: By generating the arc between the electric power electrode 1 and the position to be cut of a steel material 4 in water, the position to be cut becomes heated molten state by the arc heat, and by dropping and diffusing the produced dross, the cutting range is enlarged. Then, in the case of overlapping the AC current to the DC current, the circumference of electric way of the DC current is DC-magnetized by the generated magnetic field. By conducting the AC current into the same electric way as magnetic way of the DC current, the alternating field is generated in the circumference of the electric way, and by this alternating field, the magnetizing direction is repeatedly changed over and the magnetization is reduced. In this way, cut waste and the dross become the reduced magnetizing condition and the cutting workability is improved because these are not attracted to the cutting position by the magnetization.
TANAKA HIROTO
NOUCHI SHIGEO
ISHIKAWAJIMA HARIMA HEAVY IND