Helmut Schmidt University — University of Bundeswehr (Hamburg, Germany):

Fischer A., Mag. Eng., former Scientific Researcher

Max Aicher GmbH & Co. KG (Freilassing, Germany)

Krüger K., Dr. Eng., Prof., Chief Scientific Officer

Hüttenwerke Krupp Mannesmann GmbH (Duisburg, Germany)
Weinberg M., Dr. Eng., Head of Technological Department, e-mail: matthias.weinberg@hkm.de

For the secondary metallurgical treatment of steel, the specific purging gas flow is important to describe the process. Due to the harsh environmental conditions, a measurement of the real gas flow in the rinsing nozzle is not reliable as possible leaks reduce the actual mixing power. At a laboratory stand, the suitability of a rinsing spot and their influencing factors is evaluated. It was revealed that nozzle geometry, amount and tough properties of slag are among these factors. Options based on spectral analysis of pressure and vibration are presented to assess the process. It is possible to evaluate leaks in supplying lines and to give them quantitative determination. Additionally, efficient consumption of purging gas can be determined in industrial conditions using analysis of vibration signal. For this purpose it is necessary to provide absence of possible perturbations to a measuring signal from operating electric drives or driving systems. The suitable frequency range of a measuring signal can be determined via analysis of 3-octave and octave strips.

1. Oeters F. : Metallurgie der Stahlherstellung, Springer Verlag, Berlin, 1989.
2. Maruoka N., Lazuardi F., Maeyama T., Kim S. J., Conejo A. N., Shibata H., Kitamura S. : ISIJ Intern. 51 (2011) Nr. 2, S. 236/41.
3. Wu L., Valentin P., Sichen D. : steel res. int. 81 (2010) Nr. 7, S. 508/15.
4. BFI : Tätigkeitsbericht/Activity Report 2009/2010, VDEh-Betriebsforschungsinstitut GmbH, Düsseldorf, 2010.
5. Zierep J. Ähnlichkeitsgesetze und Modellregeln der Strömungslehre, Braun Verlag, Karlsruhe, 1990.
6. Davidson L., Amick E. H. Al-Che J. 2(1956) Nr. 3, S. 337/42.
7. Gaudlitz D. Numirische Unretsuchung des Aufsteigsverhaltens von Gasblasen in Flüssigkeiten. München. 2008.