On the Centerline Segregation of Continuously Cast Slabs

Abstract

The major factors affecting the formation of the centerline segregation in continuously cast slabs (CC slabs) and slab-shaped ingots were investigated.
The results obtained are summarized as follows.
(1) The centerline segregation in a regular CC slab is much remarkable than that of a slab-shaped ingot; the latter has the solidification structures analogous to those of the former. This result shows that the effect of the solidification shrinkage on the centerline segregation of CC slabs is small.
(2) The centerline segregation of CC slabs becomes more remarkable as the crater becomes deeper.
(3) The centerline segregation of CC slabs solidified stationarily in the secondary cooling zone is much slighter than that of the regular CC slabs.
(4) The segregation band of CC slabs consists of a lot of small segregated spots with microporosities and Mn-sulfides, where the microsegregation is much remarkable than that of the columnar dentritic zones and both the clear dentrites with the smaller secondary arm spacing and the obscure dendrites are recognized.
(5) The major factor affecting the centerline segregation of CC slab is believed to be the mechanical deformation (bulging of slab by the miss alignment etc.) at the final stage of the solidification where only the mashy zone remains.