Abstract
Presentation of special requirements for the machinability of cutting steels on metal-cutting machines causes the need to obtain steels with a normalized sulfur content. Continuous casting of such steels leads to a deterioration in spillability, which leads to a decrease in productivity and deterioration of the quality of the metal, due to contamination with non-metallic inclusions. In this paper, using THE example of obtaining С45E steel, the study of the structural features of the "build-up" extracted from the inner cavity of the immersion Cup was carried out. The study of optical (Leica 8C) and electronic (FEI Versa 3d) microscopy methods, as well as x-ray diffraction analysis (brukerd8 Advance diffractometer) found that the "growth" has a non-uniform structure. The study of the features of the structure of the "growths" on the inner cavity of the pouring cup found that the "growths" has a non-uniform structure. The surface layers of the "growths" contain refractory corundum deposits Al2O3 with a thickness of 2 to 8 mm. the Intermediate layer adjacent to the surface contains deposits of inclusions of alumomagnesial spinel MgO·Al2O3 and inclusions of calcium sulfide CaS, the thickness of the layer is from 0.8 to 10 mm, respectively. The location of the secretions in the surface and intermediate layers is layered, alternating with metal. The inner layer is coral layers of calcium sulfide CaS deposits, fusible and refractory calcium aluminates of type 3CaO·Al2O3 (TL=1535°C) and CaO·2Al2O3 (TL =1745°C). The main reason for the tightening of steel channels during casting of steel C45E is the formation of deposits CaS and MgO·Al2O3 on the inner layers of the "growths».
Keywords
Continuously cast billet, casting, regulated sulfur content, macrostructure, surface, growth, castability.