極低炭素鋼スラブの表面品質に及ぼすモールドフラックス塩基度の影響

抄録

Mold flux has a large influence to the surface quality of ultra-low-carbon steel slabs. Especially, its involvement in the continuous casting mold must be prevented in order to reduce inclusions in the surface layer of the slabs. In this work, experimental continuous cast with the pilot caster was conduct and the influence of mold flux basicity to the surface quality of the slabs was researched.
Spherical inclusions, which existed in the surface layer of the slabs and were considered to be caused by the involvement of molten flux in the mold, decreased in number or size, with the increase of mold flux basicity.
The effect by the basicity could be explained in terms of interfacial tension or wettability between mold flux and molten steel. Thus, the number and the size of spherical inclusions decreased with the increase of interfacial tension and contact angle of molten flux on the surface of molten steel. This effect was considered to be larger than that by the viscosity or density of mold flux.