Multi-field coupling traceability method for non-metallic inclusion agglomeration in continuous casting under dual-mode electromagnetic control

The agglomeration of inclusions in continuous casting blooms destroys the continuity and compactness of the steel matrix, which seriously restricts the fatigue life and corrosion resistance of the steel. A novel traceability method for the distribution of inclusions was introduced to reveal the evolution of inclusion agglomeration. This method demonstrated the position evolution of inclusions when they passed through different planes by assigning colors for inclusions. In this study, a mathematical model coupled with electromagnetic field, flow, heat transfer, solidification, and non-metallic inclusion movement was developed to study the agglomeration behavior of inclusions under dual-mode electromagnetic field control modes (edge-to-center flow mode and the coupled mode of center-to-edge flow and edge-to-center flow). Numerical simulation revealed that the coupled mode significantly enhanced inclusion distribution uniformity in the solidified shell, with a 63.7 % reduction of the number in the localized agglomeration zone compared to the edge-to-center flow mode. Experimental measurements demonstrated a 46.7 % decrease in inclusion number density near the quarter position of the loose side under coupled mode compared to edge-to-center flow mode. Under coupled mode, the flow of molten steel at the center and the edge of the mold with the opposite directions helped to disperse the inclusions and promote the uniform distribution of inclusions in the cross-section. This study provides a new strategy to suppress inclusion agglomeration in continuous casting blooms by electromagnetic metallurgy technology.