2005 Volume 91 Issue 12 Pages 847-855
Cold model experiments were carried out to understand the behavior of bubbles and liquid flow both in the nozzle and the mold during continuous casting. Distributions of pinholes and inclusions on the surface of a slab were investigated to clarify the effect of Ar gas injection. In the cold model, bubbles were generated at the exits of holes located above the sliding gate.
The mean diameter of bubbles changed in the downward and horizontal directions in the immersion nozzle due to coalescence. In the mold larger bubbles lifted up along the outer wall of the immersion nozzle through the effect of buoyancy forces acting on them, while smaller bubbles were carried in the entire mold by water issuing out of the port. The larger bubbles cause mold powder entrapment. On the other hand, the smaller bubbles are closely associated with pinholes observed in slabs.