Based on the comparison between the selected traditional basicity mold flux (TB slag) and ultrahigh-basicity mold flux (HB slag), and the large-scale application in industrial processes, some conclusion can be drawn:
(1) Compared with TB slag films, the thickness and growth speed of HB slag film are smaller, which is expected to improve the lubrication capacity of mold fluxes.
(2) Pores contribute to the surface roughness of slag films. HB films have higher roughness at the earlier stage of solidification, which decreases when the probe immersion time exceeds 15 s. For TB films, the effect of probe immersion time on roughness is not obvious.
(3) The overall porosity of HB films is higher than TB films have.
(4) Based on two years of industrial use, the HB slag improved the surface quality of slabs. No exceptional conditions like sticking breakout occurred.
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