Inclusion Particle Growth during Solidification of Stainless Steel.

Abstract

Inclusion particles in stainless steel were investigated in continuously cast slabs in a full scale caster and ingots cast in several kinds of molds under laboratory conditions. Under such conditions particle size near slab surfaces was seen to be smaller. However, it was increasing with increasing depth going into the slab interior. In order to understand the mechanism of inclusion particle growth we applied four different mathematical models to predict the size distribution of particles. Of the four, the Ostwald ripening model, usually only applied to aqueous colloid phenomena, provided the best correlation with experimental results. This suggests that particles formed during solidification grow by "diffusion coalescence" due to the difference in solubility of neighboring particles which in turn is dependent on particle size.