Numerical Modeling and Plant Trial on the Optimization of SEN Designs in a Large Round Billet Mold

Abstract

Numerical models were built and validated to analyze the flow and heat transfer in three submerged entry nozzles (SEN) and a large round billet mold. A comparative investigation of a single-port SEN and two types of four-port SEN was conducted using numerical simulation and industrial experiments, considering the effect of mold electromagnetic stirring (M-EMS). The findings indicate that the upper part of the mold exhibits increased surface activity using upward and downward four-port SENs. Single-port SEN demonstrates significantly lower velocity at the free surface (0.001 m/s) compared to four-port SENs (0.087 m/s for upward and 0.065 m/s for downward). The introduction of M-EMS activates the horizontal flow inside the mold. Additionally, the four-port SENs achieve a higher free surface temperature and demonstrate a significantly higher inclusion escape percentage than the single-port SEN. The shell thickness uniformity under four-port SENs is lower due to the convection of the steel jet. Industrial tests reveal no significant difference in corrosion among the three SENs. Moreover, the advantage of increasing the proportion of equiaxed crystals and reducing inclusion number density is observed using the four-port SENs in plant trials.