Numerical analysis of macrosegregation and shrinkage porosity in large steel ingot

摘要

A three-dimensional finite element model has been developed with heat, flow and solute transfer behaviour coupled calculation to predict shrinkage and macrosegregation defects in an as cast steel ingot. Solidification evolution and carbon segregation have been verified by previous investigations of a 3.3 t steel ingot. The heat transfer coefficient (HTC) at the ingot mould interface against temperature was researched by an inverse calculation method based on thermophysical parameters from microsegregation model and experimental temperatures. Good agreements were obtained both in range and variation trend of HTC compared with experimental results in references. Macrosegregation and shrinkage porosities were observed to accompany each other at the hot top of the rectangular ingot, which should be further investigated by numerical simulation. Applications of the model were extended to steel plants. The soundness and homogeneity of rolled blooms were both satisfied.