The diploma work deals with the influence of deoxidation in electric arc furnace on the content of non-metallic inclusions in secondary rafination. In the work describes simple and complex deoxidation and their respective thermodynamical and kinetic laws. Common deoxidants and modification of non-metallic inclusions with coated CaSi filled wire into the melt are also described. The paper deals with the production of the two steel grades in the electric arc furnace and in the secondary rafination stage and their casting. The influence of the content of non-metallic inclusions on the properties of steel is also presented.
In two batches of steel grades UTOPMO1 and two batches of UTOPMO2 we tapped the steel with two different concentrations of oxegen. The goal was to determine the acceptable high concentration of oxegen during tapping, in order to ensure an adequate amount of non-metallic inclusions. In the secondary refining stage, we observed nonmetallic inclusions after degassation and 10 minutes after shooting coated CaSi filled wire into the melt. We observed non-metallic inclusion in the cast ingots. The non-metallic inclusion were categorized on the basis of ASTM E45 method A and DIN 50602 method K and with a scanning electron microscope. With the latter we determined the influence of the degree of deoxidation on the size of inclusions of individual categories.
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