Molten Steel Level Measurement Based on Temperature Attenuation Characteristic

This paper proposes a molten steel level measuring method in a tundish. This method is based on the temperature attenuation characteristic of the temperature tube. Our previous work focused on the temperature distribution of the temperature tube which can be used for molten steel level measurement. In some continuous casters, sticky slag adheres to the tube, thus, blocking the temperature information on the tube. To avoid this problem of lacking true temperature, we analyzed the principle of adhesion and conclude that the adhesive slag thickness of the tube is influenced by whether that part of the tube contacts the slag or the molten steel prior to being lifted. Consequently, for detecting the adhesive slag thickness online with available pyrometer, a heat transfer model is established. Through analysis of the model, it was revealed that the thickness of the adhesive slag remarkably influences the measurable maximum curvature time of the temperature attenuation. In addition, this maximum curvature time is insensitive to other irrelevant factors such as initial temperature and ambient temperature. Therefore, the maximum curvature time of the temperature attenuation of the adhesive slag indirectly indicates the molten steel level. Finally, the experiments prove the feasibility and the sound accuracy of this method with the maximal error being 3 mm. This method is not only suited for the molten steel level measurement, but also applicable to other non-destructive measurement of coating layer thickness.