Effect of continuous-casting parameters on carbon segregation in SWRH82B high-carbon steel

Optimization of the continuous-casting production technology for high-carbon steel is one of the most important areas of research related to the steelmaking process. This article aims to address the problems of carbon segregation and reticulated cementite defects in the production process of SWRH82B high-carbon steel in a Chinese steel plant. In this study, Fluent software was used to perform a numerical simulation combined with experimentation to establish a heat-transfer model for the solidification of an eight-strand continuous caster. We numerically calculated the heat-transfer characteristics of the solidification and studied the effect of different parameters on the carbon segregation and inclusions of SWRH82B high-carbon steel, including casting speed, degree of superheating, and final-electromagnetic stirring of the eight-strand continuous caster. We also analyzed the relationship between the main elements during the continuous-casting process of the SWRH82B high-carbon steel and its microstructure and properties. The results indicate that carbon segregation in the center of the billet was the main cause of reticulated cementite. The degree of superheating and casting speed were then optimized, which promoted the homogenization of the components of liquid steel and reduced the inclusion content. When the degree of superheating was reduced to 25 ℃ and the casting speed was increased to 2 m·min⁻¹, the carbon segregation index of the billet was reduced from 1.17 to 1.11, the sorbite rate was 89%, the cementite network grade decreased from 4 to 1, and the C inclusions were substantially eliminated. When the end electromagnetic stirring current was set to 370 A and the frequency to 7 Hz, the carbon segregation index decreased to its lowest value of 1.04. The defects occurring in the production process of SWRH82B high-carbon steel were addressed by optimizing the continuous-casting process parameters, which provides theoretical and practical support for the high-quality production of high-carbon steel.