On the Mechanism of Steel Homogenization via Rare Earth Addition: Experimental Characterization and Numerical Simulation

Abstract Macrosegregation is one of the most typical defects during solidification which greatly limits mechanical properties key steel components. Oxygen and its inclusion have been considered to cause compositional heterogeneity in solidifying besides thermo-solutal convection. However, it still not clear how robustly reduce oxygen consequently macrosegregation widely used steels. Here, we reported mechanism homogenize via Rare Earth (RE) addition. A series experimental characterizations 3-ton bearing ingots demonstrated that RE able decrease content inclusions a lower level than conventional Al-deoxidation process. The common oxide sulfide can be modified into spherical or ellipsoidal 2 O S with dispersed distribution. multi-component/multi-phase simulations show larger size population are required trigger channel segregation due higher density compared alumina-based inclusions. theoretical calculation reveals critical eliminate dramatically increased 20 ppm, indicates risk destabilization mushy zone initiation steel. In addition, global severity reduced Such conclusion fully validated 9.5-ton 100-ton ingots. terms interaction between motion, fluid flow, solidification, this study elucidates for first time, highlights an economic, common, controllable method fabricate homogenized by