Technology for Electroslag Remelting with Rotation of the Consumable Electrode

is known that metal which is produced by the method of electroslag remelting (ESR) has service properties superior to those of metal made by open refining and casting. This can be attributed to the better conditions which exist for refining in the specially chosen slag and for the crystallization of the metal in the case of ESR. However, the need for a two-stage metallurgical conversion (essentially requiring repeat refining) makes ESR metal more expensive than metal made by electric arc refining. By resorting to out-of-furnace treatments, the content of harmful impurities in the latter product can be reduced to nearly the same level as in ESR metal. In addition, the consumption of electric power in the production of ESR ingots is more than three times greater than the level characteristic of steelmaking in electric furnaces. It is this circumstance that is presently impeding the wider use of ESR [1]. The costs of producing ESR ingots could be reduced significantly by using an electroslag remelting technology that involves rotation of the consumable electrode around its axis. The General Metallurgy Department of South-Ural State University has already had many years of experience in developing and studying an ESR process that takes place in a centrifugal force field [2–8]. Such a technology has several important advantages. Most significantly, it makes it possible to appreciably increase the productivity of the process (more than 25% in some cases) without increasing the amount of power that must be supplied to the slag bath. This is accomplished through a change in the hydrodynamic situation in the bath, a reduction in the height of the bath, and the forced removal of liquid metal from the electrode. The hydrodynamic pattern which exists during the melting of a rotating electrode is different from the pattern characteristic of an electrode that moves only vertically. An ascending slag flow is created in the zone near the consumable electrode as it rotates. While rising, the slag is heated and reaches its highest temperature in the immediate vicinity of the electrode end that is being melted (Fig. 1b). In the standard technology, slag washes over the melting conical portion of the electrode after it gives up heat to the water-cooled wall of the mold. Moving through the near-electrode region, the slag reaches its highest temperature at the boundary with the liquid metal bath (Fig. 1a). The removal of liquid metal from the electrode as …