Distribution of non-metallic inclusions in continuously cast carbon steels

Abstract

Metallurgical factors will affect the solidification structure and distribution of inclusion particles in continuously cast carbon steels. The amount of equiaxed structure increases as the temperature of the liquid steel decreases. The number of large sulphide and oxide inclusions is high close to a surface separating the equiaxed and columnar zones or where columnar zones from two different directions meet. A bow-type machine will produce a non-symmetrical distribution of solidification structures and of large inclusions. Small inclusions, however, are formed at a late stage of the freezing process and are not greatly affected by the geometry of the casting machine. A new experimental technique has been applied to examine the composition and size distribution of inclusions. The technique has been valuable in the study of nucleation and growth of oxide and sulphide inclusions.