Deoxidation of Electroslag Remelting (ESR) – A Review

Electroslag remelting (ESR) is widely used to produce some varieties of special steels and alloys, mainly because of its ability to provide high cleanliness level and excellent homogeneity of solidified ingot structure (reducing segregation, shrink holes, etc.) simultaneously.1–3) Deoxidation of liquid steel and alloy is always an ongoing concern for eliminating the detriments of oxide inclusions to the processing and mechanical properties of the steel and alloy. Great efforts have been put forward to minimize the amount of oxide inclusions by decreasing the oxygen content of the steel during ESR process.4–9) Deoxidation of liquid steel during ESR is basically different from that in other steelmaking process operations. The iron oxide activity of the slag is a measure of its oxygen potential during ESR.4,5,9,10) The intention of deoxidizing agent addition in ESR process is to deoxidize the molten slag.4–9,11,12) In this process, the oxygen level of liquid steel is determined by the interactions of atmosphere-slag-metalinclusion. Deoxidation during ESR is therefore affected by multiple factors, such as alloy compositions, deoxidizing agents, absorption ability of slag to oxide inclusions, remelting atmosphere, slag compositions, and oxide inclusion evolution. Some of these factors could only be varied in a limited range in the ESR practical production. As for a specific ESR practice, the contribution ratio of each of these Deoxidation of Electroslag Remelting (ESR) – A Review