K. Thiele1, S. Ilie2, R. Rössler2, C. Walkner3, T. C. Meisel3, T. Prohaska3 and S.K. Michelic1
1Christian Doppler Laboratory for Inclusion Metallurgy in Advanced Steelmaking, Montanuniversitaet Leoben, 8700 Leoben, Austria
2voestalpine Stahl GmbH, 4020 Linz, Austria
3Chair of General and Analytical Chemistry, Montanuniversitaet Leoben, 8700 Leoben, Austria
Improvement of steel cleanness requires detailed knowledge about the formation of non-metallic inclusions. Tracing inclusions and potential sources is an effective tool to study inclusion evolution. In the paper, different tracing approaches are evaluated. First, classical tracer experiments are performed, where rare earth elements (REE) like La or Ce are deliberately added to the melt on an industrial scale to mark the inclusions directly. Second, a multi-element fingerprint of the inclusions is compared to the multi-element pattern of potential sources such as alloying and auxiliary materials. The REE distributions’ natural element profiles are interpreted by normalizing the REE fractions to reference values. REE contents are analyzed by inductively coupled plasma mass spectrometry in all cases. Both approaches are applied to track the source of clogged material in the SEN from Ti-ULC steel production. Results show a clear connection between inclusions resulting from deoxidation and the clogged layer in the SEN.