Investigation of the melting point of the slags used in the processes of special electrometallurgy

Abstract

The development of the metallurgical industry of Ukraine to a large extent depends on the export of high quality steel, which is smelted by means of special electrometallurgy. The quality of the metal produced in process of electroslag remelting is determined by the technological properties of the slags used. In electroslag processes, the slag, which is a source of heat, performs a number of other important functions: refines metal from non-metallic inclusions, gases and harmful impurities, protects the liquid metal from interaction with the atmosphere, provides a good quality surface of the ingot. In order to use the slags of rational chemical composition, experimental studies of melting intervals were performed by optical and contact methods. Optical studies were performed at the high-temperature heating microscope MNO-2, manufactured by Carl Zeiss. The microscope was upgraded: the internal galvanometer, which introduced errors into measurement, was replaced by an external galvanometer, which was connected with platinum-platinum thermocouple. The process of slags melting was shot with a digital camera. When applying the contact method, crushed slag was put into a crucible of boron nitride and slowly heated in the furnace (0,15-0,30°С/с). The state of the slag in the crucible was evaluated by probing with a tungsten rod. The results of the experiment showed that the melting point of the slags (fluxes) during the heating of a large mass of slag in the furnace is more than the real temperature. The results of optical measurements using the microscope MNO-2 are more reliable. The experimental results obtained are in line with the literature data for fluxes with chemical composition close to the studied ones. The results of the performed research make it possible for us to recommend for industrial use the fluxes AN-14, AN-15, AN-15M, which, in addition, contain a small amount of harmful fluoride