Measurements and modeling of air gap formation in iron-base alloys

The formation of an air gap has been experimentally studied during solidification of several iron-based alloys. Air gap widths and temperature distribution have been measured during solidification in a cylindrical water-cooled Cu-mold. Mathematical modeling has been performed to increase the understanding of the solidification process and the air gap formation. A model, developed earlier for Al- and Cu-based alloys, for description of air gap formation in alloys solidifying with varying solidification intervals was tested for Fe-base alloys. The model includes the effect of formation and condensation of lattice defects on the solidification process and the air gap formation. The calculated shrinkage using this model shows good agreement with the experimental data.