Properties and structure of a new non-reactive mold flux for high-Al steel

During the conventional continuous casting process of high-aluminum steels ( w ([Al]) > 0.5 wt.%), some components of slag, such as SiO 2 , B 2 O 3 , and TiO 2 , could be reduced by aluminum in molten steel. Therefore, the CaO–BaO–Al 2 O 3 –CaF 2 –Li 2 O non-reactive mold fluxes were designed using the simplex grid method and molecular dynamics to mitigate the slag–metal interface reaction and stabilize the performance of mold fluxes. The results show that the components of non-reactive quinary system are 20–40 wt.% CaO, 14–34 wt.% BaO, 14–34 wt.% Al 2 O 3 , 4–12 wt.% F, and 4–8 wt.% Li 2 O. Molecular dynamics simulation results show that [AlO 4 ] − tetrahedron acts as network formers and melt network structure is mainly chain and lamellar in the low-viscosity area. The cross sections of w (F) = 8 wt.%, w (Li 2 O) = 8 wt.% and w (F) = 12 wt.%, w (Li 2 O) = 8 wt.% are important reference sections for the design of mold flux, with the compositions of 22–40 wt.% CaO, 14–34 wt.% BaO, 20–34 wt.% Al 2 O 3 and 23–40 wt.% CaO, 14–34 wt.% BaO, 20–28 wt.% Al 2 O 3 , respectively.