VDEh Institute of Industrial Researches (Düsseldorf, Germany):

Kordel T., Dr., Head of Project
Köchner H., Dr. Eng., Head of Dept. of Measuring Processes and Testing Equipment, herbert.koechner@bfi.de

Minkon GmbH (Erkrath, Germany):
Fischer H., Mag. Eng., Head of Technical Dept.

In ladle furnaces the liquid steel is heated up to the temperature necessary for subsequent treatment and casting. The effective liquid steel temperature at the end of the treatment is compared with the temperature aimed at after power off by thermocouple measurement. A new measurement and control method uses a continuous optical measurement technique based on BFI’s DynTemp technology for the final stage of the ladle furnace treatment. It offers a continuous temperature control allowing to monitor temperature homogenization, resulting in precisely reaching the target temperature. In this paper the measurement method is illustrated and results from continuous temperature measurements during and after heating are given. Transferability to different industrial applications is discussed. The temperature homogenization of a melt after ladle furnace treatment was discussed on the basis of continuous temperature measurements. Therefore, a novel fibre optical measurement system based on the DynTemp technique developed by BFI and licenced by Minkon was applied. It allows detailed monitoring of the temperature evolution during the homogenization phase. In the particular case of improper homogenization, unwanted temperature fluctuations of up to ±30 K were observed. In the standard case of proper homogenization stirring after heating, the development of temperature is as expected. The continuous temperature measurement also offers the possibility to optimize the duration of the homogenization stirring. Safety margins of excess temperature can be reduced resulting in reduced process time, energy and purging gas consumption as well as refractory wear. This technique can also easily be applied to different metallurgical aggregates for steel production.

1. Köchner, H.; Lamp, T.; Fischer, H.: Continuous optical temperature measurement for liquid steel temperature control, Proc. EECR Steel 2011, 28 June – 1 July 2011, Düsseldorf.
2. Kordel, T.; Lamp, T.; Köchner, H.; Fischer, H.; Zagrebin, V.: stahl u. eisen 132 (2012) Nr. 7, p. 92/94.
3. Köchner, H.; Lamp, T.: stahl u. eisen 129 (2009) Nr. 3, p. 39/45.