Modeling and predication of shrinkage porosity formation in steel ingot

Abstract

In order to predict distribution of shrinkage porosity in steel ingot, the feeding process in mushy zone during solidification of steel ingot was analyzed and modeled. G 2·L −5/3 (where G is temperature gradient and L is cooling rate) was put forward as shrinkage porosity criterion. Effects of liquid fraction and specific surface area of dendrites on permeability were both taken into consideration. Integrals with respect to interdendritic feeding flow velocity and pressure drop were evaluated. The derived expression reveals that: the smaller G 2·L −5/3 value is, the higher the critical temperature can be, and the severer shrinkage porosity would occur. Predicted distribution of shrinkage porosity in a 5.5 ton 2Cr13 ingot using criterion G 2·L −5/3<143 agrees well with experimental sectioning results. Using criterion G 2·L −5/3, an optimization of the 5.5 ton 2Cr13 ingot design was carried out aiming at eliminating shrinkage porosities in the ingot and improving metal yield effectively.