To keep the surface of molten steel in a mold to a fixed level which preventing the malfunctioning of positional measurement of the molten steel surface and to enable the stabilization of quality of a cast slab by supplying plasma current into the molten steel in a tundish between a torch and an anode at out of the position of a level sensor.
A fixed frequency of signal is inputted into the level sensor in the mold and the distance between the level sensor and the molten steel is measured with a coil in the level sensor by reflected magnetic field of the eddy current generated in the mold. The plasma current is supplied into the molten steel in the tundish between the torch and the anode at out of the position of the level sensor for measuring the position of the molten steel surface in the mold. That is, the plasma current course is constituted at out of the position of the level sensor for measuring the molten steel surface position in the mold to eliminate the effect caused by the generated magnetic field from the plasma current to the level sensor. By this method, since the malfunctioning of the measurement is prevented and the molten steel surface in the mold is kept to the fixed level and continuous casting can be executed, the quality of the cast slab is stabilized.
ISHII NARUNOBU
SHINODA TSUYOSHI
SATO SHINJI
