Abstract:The morphology and composition of inclusions in titanium-bearing wire steel were observed by scanning electron microscopy, and the formation and evolution of inclusions during smelting were particularly analyzed. The results showed that the typical inclusions before LF treatment were spherical SiO2-Al2O3 composite inclusions, the size of which was about 6 μm. In the LF refining process, the SiO2-Al2O3 type inclusions were transformed into irregular ellipsoidal SiO2-Al2O3-CaO inclusions with a size of 5-10 μm. And as the refining progresses, the number density of inclusions decreased from 131.81 before the LF treatment to 42.84/mm2 at the end of LF treatment. During the molten steel refining, the inclusion composition moved were transferred from the initial w(Al2O3)<20% region to the region where the CaO content increased, and the mass fraction of Al2O3 was 20% to 35%. In addition to the SiO2-Al2O3-CaO inclusion, there were many near-spherical SiO2-Al2O3-CaO-MgO and irregularly SiO2-Al2O3-CaO-MgO-TiOx inclusions after LF refining. Also, the precipitation of TiN inclusions occurred in the outer layer of the composite oxide inclusion in the slab. The inclusion component eventually stayed in the area of w(Al2O3)<25% in the slab, and the number density decreased to about 27/mm2.
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