Effect of CaO‐Al ₂ O ₃ ‐Based Slag Entrainment on Composition and Inclusion Evolution of High‐Mn Cryogenic Steel in Mold

Clarifying the effect of slag entrainment on the quality of high‐Mn cryogenic steel is necessary. In this paper, thermal simulation experiments were conducted to investigate the changes in steel composition and the formation and evolution mechanism of inclusions in the steel within different residence times, when the CaO‐Al 2 O 3 ‐based slag was entrained into the steel. The results show that as the residence time increases, the amount of mold flux in the steel decreases gradually. And the contents of Mn and Si in the steel gradually decrease, the content of Al first increases and then decreases, while the Cr content fluctuates within the range of 0.07 wt%. MnO and Cr 2 O 3 are generated by the oxidation of Mn and Cr in the steel, and a portion of them floats up to the vicinity of steel–slag interface to form a MnO‐Cr 2 O 3 ‐enriched layer. The retained MnO in the steel reacts with CaO and Al 2 O 3 in the slag to generate calcium aluminate inclusions and manganese‐aluminum spinel inclusions. Under the slag entrainment condition, Mn and S in the steel form brittle MnS‐Al 2 O 3 composite inclusions with Al 2 O 3 as the core, which can significantly increase the probability of crack initiation of the solidified shell.