A. Arefpour - Department of Materials Engineering, Najaf Abad Branch, Islamic Azad University, Esfahan, Iran
A. Monshi - Department of Materials Engineering, Najaf Abad Branch, Islamic Azad University, Esfahan, Iran
A. Saidi - Department of Materials Engineering, Najaf Abad Branch, Islamic Azad University, Esfahan, Iran
T. Khayamian - Department of Materials Engineering, Najaf Abad Branch, Islamic Azad University, Esfahan, Iran

Mold powders in continuous casting of steel contain fluorine through mainly CaF۲ and occasionally NaF and Na۳AlF۶. Fluorine develops dangerous gases such as SiF۴ and HF at high temperatures. In this study, CaF۲ is partly replaced by substances such as Na۲CO۳, ZnO and Fe۲O۳.Sulfur free Portland cement clinker containing gypsum was used as a new product base. These additions developed comparable viscosity to the industrially used powder. In order to compare the viscosity of laboratory samples with the reference sample, study the crystalline behavior of samples, and compare them to the reference sample, there were performed sloped plate groove viscometer, XRD and SEM studies. It can be detected the Crystalline phases such as Gehlenite, Nepheline, Akermanite, Cuspidine, Na۲ZnSiO۴, Ca۲ZnSi۲O۷, Ca۳SiO۵ and Mn۳O۴, Fe۲SiO۴. In order to develop less toxic mold powder in continues casting of steels, it is proposed being crystalline and glassy with comparable viscosity.