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Abstract

The project aimed at avoiding emissions from continuous casting fluxes containing volatile fluoride and alkali compounds which are considered health-injurious and cause corrosion of casting machine parts. The objectives of the project were to substitute less harmful additives for the volatile fluoride and alkali compounds and to modify powder manufacturing and conditioning for the reduction of fluoride volatilisation.

In the experimental powders, CaF(2) and Na(2)O were partially or totally replaced by Li(2)O which is chemically more stable and has a strong fluxing ability. A series of industrial trials was performed with various mould powders and granules using different steel grades and strand sizes. Optimisation of flux composition and performance is envisaged, especially in view of surface quality and cleanness of steel in the case of billet and bloom casting. In the basic slag system CaO-Al2O3-SiO2, the eutectic composition at 1 266°C with moderate Na(2)O, K(2)O and F contents is recommended, leading to a preferred glassy solidification of the mould fluxes.

In stainless steel-making processes using CaO- SiO(2)-Al(2)O(3)-MgO slags, CaF(2) fluxing additives cause remarkable refractory wear. Therefore, alternative fluxing agents such as MgO-Al(2)O(3) and MgO-CaO were tried with the aim of reducing the refractory lining attack without losing control of the inclusion composition of steels. The results are encouraging, but a larger number of steel heats have to be tested to secure a reliable long-term performance.

Additional information

Authors: JANKE D, TU Bergakademie, Institut für Eisen- und Stahltechnologie, Feiberg (DE);SCHULZ T, TU Bergakademie, Institut für Eisen- und Stahltechnologie, Feiberg (DE);TONELLI M, CSM, Roma (IT);CIMARELLI T, CSM, Roma (IT);HOLLAPPA L, Helsinki University of Technology, Department of Materials Science & Rock Engineering, Laboratory of Metallurgy, Helsinki (FI);SHILOV A, Helsinki University of Technology, Department of Materials Science & Rock Engineering, Laboratory of Metallurgy, Helsinki (FI);HAVETTE E, Ugine-Savoie-Imphy, Ugine (FR);VIGUET-CARRIN C, Ugine-Savoie-Imphy, Ugine (FR);VALENTIN P, Saarstahl, Völklingen (DE);BRUCH C, Saarstahl, Völklingen (DE)
Bibliographic Reference: EUR 20645 EN (2003), 137pp. Euro: 25.00
Availability: EUR-OP reference: KI-NA-20645-EN-S Available from EUR-OP sales agents URL: http://publications.eu/general/en/publications_en.htm
ISBN: ISBN: 92-894-5327-3
Record Number: 200316177 / Last updated on: 2003-04-22
Category: PUBLICATION
Original language: en
Available languages: en