Numerical modeling investigation of Planar Flow Casting for Fe-6.5wt%Si alloy

Fe-6.5wt%Si alloy possesses excellent electromagnetic properties, including high resistivity, low iron loss, high magnetic permeability, and almost zero magnetostriction coefficient, making it an ideal core material for low-noise and low-iron-loss applications. However, the higher silicon content promotes the formation of ordered phases B2 and D0 3 , which significantly increases the material’s brittleness. Traditional rolling processes are inadequate for producing Fe-6.5wt%Si alloy thin ribbons. Planar Flow Casting, on the other hand, has a high cooling rate, which can suppress the formation and growth of ordered phases in high-silicon steel, reduce the material’s brittleness, and produce Fe-6.5wt%Si alloy thin ribbons. However, Fe-6.5wt%Si alloy ribbons produced by Planar Flow Casting have gaps on the as-cast surface and micro-roughness defects on the free surface at small scales. Simulation results indicate that the gap on the as-cast surface is caused by the formation of air-pocket due to the entrapment of gas into the puddle. The presence of air-pocket can affect the heat transfer between the melt and the cooling roll, consequently influencing the fluid velocity and causing fluctuations on the free surface, and even leading to fracture of the thin ribbon. The wetting behavior of the melt on the cooling roll surface influences the entrainment of air-pocket, and favorable wetting conditions can reduce the entrainment of air-pocket, thereby improving the surface quality of the alloy thin ribbon.