چكيده به لاتين
Mold powder compounds are used in continuous steel casting. Mold powders are added to the melt inside the mold. The two important roles of mold powder are the lubrication of the frozen steel strand and the control of thermal conductivity between the mold and the molten steel. Mold powders are also used to prevent heat loss and re-oxidation of molten steel. In continuous casting processes, in order to maintain the surface health and reduce the surface cracks of the casting ingot, it is desirable to control the heat flux, which is mainly done by mold powders. Sometimes, to prevent the creation of dust and environmental factors, as well as to create proper flow and to be able to automatically add these powders to the continuous casting mold, this product is produced in granular form. The main composition of these powders is CaO, SiO2, CaF2, Al2O3, Na2O and other alkaline and alkaline earth oxides. In this research, firstly, two samples of granule mold powder used in Khuzestan Steel Company were examined, and then a general formula was considered according to them, and then, considering the constant C/S ratio, oxides such as MgO, Li2O and K2O were added by weight percentages of 2 and 4% compared to sample 1. Also, in the two samples, the weight percentage ratio of sodium oxide to alumina was changed and properties such as melting temperature, crystallization temperature, viscosity and phase structure of the compounds were investigated. Also, a mold powder sample was made in the form of granules, in which properties such as filling density and strength of the granules were checked. The results showed that alkaline oxides can reduce the viscosity to some extent, and the largest decrease in viscosity was related to the samples containing lithium oxide, and also adding alkalis can increase the percentage of the final crystalline phase. The dominant crystallized phase in all samples after melting and then heat treatment at 900°C for one hour was the cuspidine phase.
