Liquefaction Controlling Components and Their Effect on Carbon-Free Mold Powders

Publikation: Beitrag in FachzeitschriftArtikelForschungBegutachtung

Abstract

In the continuous casting of ultra-low carbon steels, recarburization from the mold powder negatively affects steel quality. Therefore, to develop mold powders without free carbon, different carbides or nitrides have been proposed and evaluated in laboratory and field studies. Among these, SiC and Si 3N 4 were selected for the present study. Additionally, thermodynamic calculations were performed to quantitatively describe their effect on the melting behavior of the mold powder. To verify the results under high heating rates, mixtures of raw material components were placed in a steel crucible with a lid, inserted into a furnace preheated to different temperatures, and investigated mineralogically. The results agreed with those of the thermodynamic calculations. Moreover, the results suggested that Si 3N 4 and SiC were suitable raw material components and alternatives to carbon in the mold powder. They prevented solid–solid reactions between raw material components to form new phases and were still found at the temperature of 1200 °C. Consequently, the CaO/SiO 2 ratio was higher before oxidation and affected the liquid-phase formation. The addition of antioxidants reduced the liquefaction-controlling effect of SiC. Additionally, the study shows that the sample preparation impacts the phase formation: granules facilitate phase formation due to a higher contact of reactants, further they show earlier melting close to their surface as sodium content is increased there by the spray drying procedure.

OriginalspracheEnglisch
Seiten (von - bis)pages 3092–3100
Seitenumfang9
FachzeitschriftMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Jahrgang54.2023
AusgabenummerDecember
DOIs
PublikationsstatusVeröffentlicht - 30 Aug. 2023

Bibliographische Notiz

Funding Information:
The authors gratefully acknowledge the funding support of K1-MET GmbH, a metallurgical competence center. The research program of the K1-MET competence center is supported by COMET (Competence Center for Excellent Technologies), the Austrian program for competence centers. COMET is funded by the Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology, the Federal Ministry for Labour and Economy, the Federal States of Upper Austria, Tyrol, and Styria as well as the Styrian Business Promotion Agency (SFG). Furthermore, thank goes to Upper Austrian Research GmbH for their continuous support. In addition to public funding from COMET, partial financing comes from the industrial partners RHI Magnesita, voestalpine Stahl, and voestalpine Stahl Donawitz and the scientific partner Montanuniversitaet Leoben.

Publisher Copyright:
© 2023, The Author(s).

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