Chill Cooling for the ElectroMagnetic Levitator in relation with Continuous Casting

Kurzfassung

The project “Chill Cooling for the ElectroMagnetic Levitator in relation with Continuous Casting” aims to develop a device to directionally solidify steel samples. This contribution will present the device developed for parabolic flights using the TEMPUS facility as well as for the TEXUS 46 sounding rocket using the EML-3 facility. It consists of a Si3N4 plate that can be put into contact with a levitated and melted steel droplet. Thanks to on-board video monitoring with a high-speed camera, the time evolution of the sample geometry is recorded during solidification. The position of the growth front can be tracked. Pyrometers also register the thermal history. Analyses of the experimental results show a deformation of the sample geometry from its initially almost spherical shape. Very distinct cooling rates are also recorded close to the plate and at the free surface of the sample. Thermo-mechanical modeling was developed and applied to the TEXUS-46 experiment. Several materials properties are measured or extracted from the databases, while others are not well known. Simulations permit to identify limitations linked to properties, and more particularly the role of the mechanical behavior within the mushy zone in order to simulate the shape evolution of the sample. Coupling is achieved between the deformation of the solid and the fluid dynamics. This also includes the variation of the density of the phases for tracking the effect of shrinkage. Finally, a macrosegregation map can be computed for solute specie. It reveals the effect of the deformation and contraction induced solid velocity on the fluid flow and solute mass transfer.