Alteration of Refractories of High Frequency Induction Furnace during Steel Refining under Vacuum and/or Atmosphere

Abstract

In the refining of steels with the high frequency induction furnace, some reactions arise between the furnace refractory and molten steel. Then, the high temperature properties of refractory affect on the furnace life.
In this paper, with the vacuum and atmospheric induction furnace, the alteration of refractories after the melts being charged were studied by the macroscopic and microscopic observations, chemical analysis and X-ray diffraction method. The relation between the alteration of refractories and the refining of the molten steel was also discussed.
The results were as follows:
1. The alteration of the furnace refractories was much affected by the atmospheric conditions, the chemical composition of steel melts and the characteristics of refractories such as compound constituent, particle size distribution and casting method.
2. The deep penetration of the molten steel into the refractory through cracks and the metal deposition on the vacancy in the refractory were observed. These metals gave some alterations in surroundings.
3. The inner surface of furnace refractory was probably kept in fused or partially fused state, because some complex oxides were produced by the reaction between molten steel and refractory materials.
4. The thin film of molten steel was spread on the surface of refractories after tapping and oxidized. The alteration of refractories occursed by the chemical reaction with this oxidized film and the diffusion of it.