Solidification Microstructure and Eutectic Carbide Control Strategies in Electroslag Remelting of Special Steels and Alloys: A Review

Electroslag remelting (ESR) is widely used to produce some varieties of high-quality special steels and alloys because of its ability to provide high cleanliness level, superior chemistry homogeneity and solidification structure of as-cast ingot simultaneously. The microsegregation, coarse eutectic carbides, and macrosegregation that are present in as-cast ingots produced by ESR severely limit the performance enhancement and application expansion of high-quality special steels and alloys. This review reveals the solidification characteristics of as-cast ESR ingots, discusses the formation mechanisms and detrimental impacts of microsegregation and macrosegregation, and clarifies the precipitation characteristics and mechanisms of various eutectic carbides. The research progress on the refinement of solidification structure, the alleviation of microsegregation and macrosegregation, and the reduction in size and amount of eutectic carbides in electroslag remelted special steels and alloys is assessed in terms of the optimization of process parameters, microalloying modification, and recent advances in ESR technologies. The key challenges of the control strategies are outlined, and the prospective advancements in the solidification microstructure and eutectic carbide control in electroslag remelting of special steels and alloys are delineated.