Исследование влияния режима обработки стали ферросиликоалюминием на ее металлургические свойства

The research and development of ferrosilicoaluminium smelting technology using carbonaceous raw materials from the Kuu-Chekinsky coal field (the Karaganda region, Kazakhstan) is aimed at the expansion of the raw material base for smelting a new type of a complex alloy with the comprehensive study of experimental raw materials and their behavior in high-temperature conditions. Increased demand in the market of high-quality metal products makes us look for the new types of ferroalloys and deoxidizers, which are complex alloys. Ferrosilicoaluminium is one of the most effective complex alloys, the use of which in the processing of steel improves its quality characteristics and reduces its cost. The article presents the study results on determining the effect of the treatment mode of steel with ferrosilicoaluminium of FS55A20 and FS55A15 grades on the metallurgical properties of steel samples. The latter have been smelted in an induction laboratory furnace UIP-25 with an upgraded cooling system in a weakly oxidizing medium by remelting. The study is given to the influence of deoxidizer nature on the indicators of metallurgical quality of steel including the index of non-metallic inclusion contaminations, the nature of non-metallic inclusions, the degree of chemical liquation, and the grain score. The methods of chemical, electron microprobe, and microstructure analyses are used. Comparison of experimental samples suggests that, all other conditions being equal, the FS55A20 alloy used for deoxidation has a more favorable effect on the metallurgical quality of steel than the FS55A15 alloy according to the estimated parameters including the average grain score, the liquation degree, and the contamination index. In case of deoxidation with the FS55A15 alloy the contamination index increases by 17%. Using the method of electron microprobe analysis the nature of non-metallic inclusions represented by 4 groups including oxides, sulfides, silicates and an unidentified phase, the proportion of which varies within 10-15% has been identified.