Fluorine‐Free Mould Powders for Billet Casting – Technological Parameters and Industrial Tests |
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Authors: | Jeferson L Klug Daniel R Silva Suzana L Freitas Márcia M S M Pereira Nestor C Heck Antônio C F Vilela Detlef Jung |
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Affiliation: | 1. PPGEM/UFRGS (Program of Postgraduate Studies in Mining, Metals and Materials Engineering of the Universidade Federal do Rio Grande do Sul), Av. Bento Gon?alves, 9500 – Setor 4 – Pre′dio 74 – Sala 211, Campus do Vale, CEP 91501‐970, Porto Alegre/RS, Brazil;2. STOLLBERG DO BRASIL Ltda., Member of the S&B Group Rua Milton José Nunes Fernandes, 1315, Chácara Santa Maria I, Pólo Industrial II, CEP 12522‐450, Guaratinguetá/SP, Brazil |
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Abstract: | There is a clear trend in industry to eliminate fluorine from metallurgical slags. Regarding the continuous casting process, fluorine in mould powders is undesirable due to the following reasons: (i) evolves easily from slags producing health‐injurious gaseous substances like hydrofluoric acid, (ii) creates problems for storage and utilization of solid waste, and (iii) causes machinery corrosion. A collaboration among universities, mould powder supplier, and steel producer was established, aiming for the development of a new F‐free mould powder for billet casting. Firstly, technological parameters for a particular composition were determined: melting characteristics, viscosity, melting behavior, and crystallization tendency. Afterwards, industrial trials were performed in a Brazilian steelworks, doing some evaluations during the continuous casting process, such as ΔT between water cooling inlet and outlet, slag pool thickness, melting performance, powder consumption, Al2O3 pick‐up, and effect on SEN erosion. Comparable surface quality for the billets was obtained when using the F‐free mould powder, since the amount of scrap produced during the rolling process was not critical. |
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Keywords: | metallurgical slags billet casting fluorine‐free mould powder |
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