Initial Solidification Behavior of Spring Steel Billet Near the Mold Corner During Continuous Casting Process

Strand surface defects originate from the initial solidification of molten steel in continuous casting mold. This article investigates the initial solidification behavior during the continuous casting of 55SiCr spring steel billet using a novel mold simulator. First, the high-frequency responding temperatures and high-frequency heat fluxes across the mold corner and hot face are calculated by the 2D-inverse heat conduction program mathematical model and the fast Fourier transformation, and the results indicate that the temperature variations and heat flux fluctuations around mold corner are stronger than those at mold hot face. Then, the characteristic heat fluxes around the meniscus at mold corner and hot face are analyzed, and their four corresponding signals are discussed with the help of power spectral density analysis. The average solidification factor K for shell corner is greater than shell face, which indicates that the cooling intensity of shell at corner is stronger due to the two-dimensional heat transfer near mold corner, as demonstrated by heat transfer and dendrite structure analysis. Finally, the interrelations between the shell profile, mold oscillation, heat flux change rate, high-frequency heat flux, temperature change rate, and high-frequency temperature for the two cases are discussed. This article investigates the initial solidification behavior of 55SiCr spring steel billet using a novel mold simulator. With the help of the 2D-inverse heat conduction program mathematical model, the fast Fourier transformation, and power spectral density analysis, the interrelations between shell profile, mold oscillation, heat flux change rate, high-frequency heat flux, temperature change rate, and high-frequency temperature are discussed.image (c) 2024 WILEY-VCH GmbH