Comments on oxide inclusion formation/removal in the ESR process

Abstract

ABSTRACT There are numerous studies of inclusions in ESR material but several questions remain as to the way in which they are removed and formed during the process. We present a critical survey of the existing data with the intention of assembling what is currently known of the mechanisms and from that survey presenting the potential routes for the inclusion behaviour. We conclude that there is a significant difference in inclusion comportment between that in small furnace processing and that in large industrial operations. The difference arises in the temperature regime, metal residence time in the reaction zones and in the operating differences in the electrode melting geometry. As a result, it is also concluded that care must be taken in relating experimental data from laboratory ESR furnaces directly to describing inclusion reactions in the industrial process. Additionally, mechanical property results obtained from small ingots, which are influenced by inclusion content, should not be taken as the same properties of ingots made on the industrial scale.