Local temperature and voltage in the molten flux and metal pool beneath the electrode of ESR porcesses were measured directly by a bare hot junction of W-WRe thermocouple.
The temperature in the flux during remelting was almost uniform at 1750±30°C. No temperature gradient was found at the metal pool-flux interface. The temperature in the metal pool decreased smoothly downward in the pool with a platea at 1500°C which was the liquidus temperature of the steel used.
The iso-voltage line was densely distributed at the electrode-flux interface and broadened toward the metal pool-flux interface. Most of the “Joule heat” in the flux was generated very close to the electrode. However, Faradaic heat generation at the electrode-flux interface was hardly found.
It is suggested from the experimental results that refining processes, not only slag-metal reaction but also inclusion removal take place mainly at the metal pool-flux interface. Because the temperature in the flux was uniform even with the localized heat generation, a violent convection should exist in the flux.
One of the driving forces for the convertion, the pinch effect of the current, was calculated. The selection of the proper voltage and current in order to have a good shape of the metal pool was suggested on an I-V diagram.
