STIRRING OF METAL MELTS FOR IMPROVING THE EFFICIENCY OF THE “LADLE – FURNACE” UNITS Message 2. NEW METHOD FOR ELECTROMAGNETIC STIRRING OF METALLIC MELT IN “LADLE – FURNACE” UNIT

Abstract

The features of refractory lining’s wear of “ladle – furnace” unit at work on metallurgical mini-plant with intensive stirring of liquid metal by gas and electromagnetic field is studied. It was established that the most affected areas are slag zone, ladle’s bottom, as well as side wall, near which the electromagnetic stirrer is located. The stability of these areas determines the duration of the ladle working between repairs. Recommendations for recovery of the lining’s working layer have been developed. Also, there are formulated the requirements for rationalization of melt stirring modes. Theoretical studying of influence of electromagnetic stirring on heat & mass transfer processes in liquid metal bath of metallurgical aggregates (in particular, during homogenization of alloy in free turbulence mode at input of additives) was investigated. New electromagnetic stirrer was designed in the PTIMA NASU, and it is proposed for technologies of melting and finishing of alloys. The stirrer creates the pulsating magnetic field, and its force lines spread equally intensively both in the horizontal and vertical planes. It is shown that design of developed stirrer, its power supply by industrial frequency 50 Hz, and physical nature of the generated field’s action provide the simplicity of its making and operation. So, new stirrer has essential technical, economic and technological advantages in comparison with known stirrers of travelling magnetic field at the same parameters of electromagnetic systems. Joint research performed by specialists of the PTIMA NASU and IED NASU with using mathematical modeling and experiments on aluminum melt showed the following. It is possible to realize a wide range of stirring modes, both intensity and melt movement directions. Thus, the application of developed electromagnetic stirrer in the “ladle – furnace” units will allow to significantly expand the possibilities for finishing liquid alloys on chemical composition and temperature, especially at small metallurgical plants.