Thermal Simulation Prediction of the Solidification Microstructure of High-Simnti Steel Slab at Different Drawing Speeds

The solidification structure of a continuous-casting slab of high-SiMnTi steel at different drawing speeds was predicted by performing experiments using a thermal-simulation device for dendrite growth. The microstructure of a characteristic cell of the solidified steel was mainly composed of fine equiaxed crystals in the chilling region, coarse equiaxed crystals in the core, and columnar crystals in between. Increasing the drawing speed of continuous casting improved the quality of the slab. When the drawing speed reached 1.2 m/min, the proportion of equiaxed crystals in the core was approximately 64.2%, and the degrees of segregation of the major solute elements, C, Mn, Si, and Ti, were the lowest (1.02, 0.98, 0.74, and 1.13, respectively). Our strategy to optimize the continuous-casting process was to adjust the parameters such that the slab more easily experienced CET transformation and had a larger chemical supercooling width. Therefore, our study provides an effective means of characterizing and a technical reference for the continuous casting of high-SiMnTi steel, and enables its process optimization.