Tata Steel Technical (Ijmuiden, Netherlands):

Tiekink W., Dr. Eng., e-mail: wouter.tiekink@tatasteel.com

Overbosch A., Doct. Cand.

Broersen P., Eng.

Alders L., Mag. Eng.

Tata Steel Strip Products Mainland Europe (Ijmuiden, Netherlands):

Kooter R., Eng.

Tata Steel Research and Development IJTC (Ijmuiden, Netherlands):

Rijnders M., Dr.

Alloys used to produce the correct steel grade in the steel plant contain several impurities. These impurities can cause unwanted effects, especially casting problems are observed if the impurities can react with inclusions in the steel. The behaviour of the impurities, which stem from the added alloys, in the steel is different if the impurity is present in a metallic state or if it is bound to oxygen or sulphur. Examples show an effect of magnesium in sponge titanium and of oxygen in ferrotitanium but the effect of oxygen in ferromanganese stays unclear. The sampling of steel itself may have an effect on the inclusions as was shown with the Mn-oxides discerned in Al-killed steel, when the sample was taken right after tapping. In contrast to the above, it was found that relatively small amounts of Mg in the sponge Ti (Mg was in all cases smaller than 0.1% mass content) can be a cause of ladle clogging in IF steel grades. Ferro-titanium-70 alloy contained a lot of oxygen but no negative effects on casting were observed that could be related to the oxygen in the alloy. It was observed, though, that mostly pure alumina clusters formed after the addition of FeTi-70, probably by a reaction of the aluminium and oxygen present in the alloy. Aluminum titanate (Al₂TiO₅) complexes were not observed, which were apparently not stable during alloying at the RH-OB [5…7].Analysis methods such as automated SEM (Scanning Electron Microscope) are a helpful tool to judge impurities in alloys that may be a cause for problems in steelmaking or casting. Alloys can have unwanted impurities that may cause problems during casting. By knowing what is inside an alloy and what may be the effect on steelmaking and casting, a steelmaker may be able to optimize his ladle treatment and in some cases his casting operation.

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2. Simpson, I.; Moore, L.; Lee, M.; Jahanshahi, S.: ISS Trans., Iron Steelmak. 29 (2002) No. 3, pp. 53/59.

3. Tiekink, W.; Overbosch, A.; ten Bras, P.; de Weerdt, J.; C. van Hoek, C.; R. Kooter, R.: Aspects of traces in alloys and some effects on steelmaking and casting, 8th Int. Conf. on Clean Steel, 14–16 May 2012, OMBKE, Budapest, Hungary.

4. Tiekink, W.: Al₂O₃ in steel and its transformation with calcium, University of Delft, The Netherlands, 2012, ISBN 978-90-805661-0-1, pp. 48 (PhD thesis).

5. Matsuura, H.; Wang, C.; Wen, G.; Sridhar, S.: The transient evolution of inclusions in deoxidized Fe-Ti-Al-O melts, Proc. 4^th Int. Congr. on Science and Technology of Steelmaking, Gifu, Japan, Oct 2008, pp. 424/27.

6. Ruby-Meyer, F.; Lehmann, J.; Gaye, H.: Scand. J. Met. 29 (2000) No. 5,pp. 206/12.

7. van Ende, M.-A.; Muxing Guo, M.; Dekkers, R.; Burty, M.; van Dyck, J.; Jones, P. T.; Blanpain, B.; Wollants, P.: ISIJ Int. 49 (2009) No. 8, pp. 1133/40.