Numerical Simulation of the Formation of Channel Segregation During the Electroslag Remelting Process

Electroslag remelting (ESR) as a widely used procedure could refine metals to achieve high-quality properties. Channel segregation, also known as freckle, is one of the most harmful macrosegregation patterns in ESR ingots, resulting in poor tensile strength or toughness. However, the formation mechanism and the control strategy of channel segregation in the ESR process have not been fully investigated. Herein, a continuum macrosegregation model is established to investigate channel segregation formation of a 30CrMnSiNi2A alloy ingot with an average diameter of 720 mm. Firstly, the solidification path adopted in this article is validated with thermodynamic calculation results, and channel segregation results calculated from the proposed macrosegregation model are compared with experimental data. Then, the flow, solidification process, and macrosegregation during the ESR process are detailed studied. Furthermore, the formation mechanism of channel segregation including the position of R/2 and the growth direction of V-shape is proposed. Finally, the effect of the processing parameter (the melting rate) on channel segregation is discussed, and advice on using lower melting rates for decreasing channel segregation is provided. This proposed model could assist in further understanding the formation of channel segregation and setting suitable processing parameters for the desired products with high quality.