Microsegregation and solidification characteristics of an advanced high strength steel – part II: experimental validation

Abstract

Good knowledge of the redistribution characteristic of solute elements is essential for the design and the production of new alloying systems. Part I of this series demonstrated the deviations of microsegregation predictions on an advanced high strength steel (AHSS) caused by equilibrium partition coefficients based on the analytical microsegregation model. In this study, the aim is to conduct a feasible experiment to assess the microsegregation and solidification characteristics of the AHSS steel and to validate the effect of partition coefficients on microsegregation predictions. The SQ method (solidification followed by quenching) was adopted for validation in this study. Solid fraction evolution was obtained on the basis of quenched solidification microstructures to compare with predicted solidification paths. Subsequently, EPMA mappings were performed on quenched microstructures to generate the concentration profiles of Mn in the liquid phase, and the measured data were used to assess the predicted degree of microsegregation.