Formation Mechanism of Transverse Cracks in Continuous Casting of 20Mn23AlV Steel

The formation of transverse cracks during the continuous casting of high‐manganese and high‐aluminum steels remains a critical challenge affecting steel product quality and performance. In this study, the formation mechanism of transverse cracks in 20Mn23AlV steel is investigated through microscopic morphology analysis, thermodynamic calculations, and high‐temperature ductility evaluations. Cracks are found to propagate along austenite grain boundaries with significant accumulation of AlN inclusions. Factsage calculations indicated that under industrial casting conditions, AlN inevitably precipitates above 1300 °C, thereby exacerbating intergranular brittleness. Hot ductility tests confirmed poor high‐temperature ductility, with inclusions detected at fracture surfaces. Furthermore, steel‐flux reactions during casting are analyzed, revealing that substantial variations in mold flux composition altered its crystallization behavior, heat transfer characteristics, and viscosity. These property changes further contributed to uneven cooling and thermal stress accumulation. Taken together, the results indicate that the combined effects of AlN‐induced intergranular brittleness and mold flux property deterioration constitute the primary mechanism driving transverse crack initiation and propagation in 20Mn23AlV steel during continuous casting.