Contactless inductive flow tomography: principles and application to a model of continuous casting

T Wondrak, F Stefani, K Timmel, V Galindo, T Gundrum and G Gerbeth Forschungszentrum Dresden-Rossendorf, P.O. Box 510119, 01314 Dresden, Germany

t.wondrak@fzd.de

ABSTRACT

In many metal casting processes the flow structure in the mould is very important for the produced material. For instance the flow field in the mould in the continuous casting process plays an important role for slug entrainment and surface defects. The measurement of that velocity field is very difficult due to the opaqueness and the high temperature of the liquid steel. One possible measurement technique is the contactless inductive flow tomography (CIFT), which is able to reconstruct the three dimensional velocity field in electrically conducting melts from externally measured induced magnetic fields.

Since for thin slab casting the velocity can be assumed to be mainly two-dimensional it is sufficient to apply only one external magnetic field and to measure the induced fields at the narrow faces of the mould. We utilize CIFT for visualizing the flow of GaInSn in a model of continuous steel casting. In a first step we show that a numerically determined flow field can be reconstructed by CIFT with an empirical correlation coefficient of nearly 80 per cent. Then we apply the method to the real model and show that typical flow features can be reliably detected.

Keywords velocity measurement, liquid metals, continuous casting