Komarov V. Improvement of the method of non-metallic inclusions removing by influencing the transfer processes in the melt in the cavity of the tundish ladle

The dissertation is devoted to the decision of an actual scientific problem of development on the basis of the established hydro and gas dynamic laws and the formulated mechanism of nonmetallic inclusions removal of refining technology of liquid metal in a tundish ladle by means of the formulated criterion of intensity of melt–slag interaction processes on the basis of proposed method of the qualitative analysis of structure of streams of melt in a tundish ladle and their turbulence. The criterion of intensity of melt – coating slag interaction processes is formulated. The criterion helps to find the maximum allowable modes of action on the melt considering a combination of factors: melt circulation intensity, degree of turbulence and bubble purge intensity. A method of analysis of the structure of melt flows via identification of characteristic zones of flow and calculation of the average kinetic energy, as well as energy of turbulent motion, for the whole volume and individual zones has been proposed for the tundish ladle. The method is preferred over the known approaches (based on cells of perfect mixing and displacement) which use the situational way of demarcation of zones in the volume of the metallurgical device, due to ability to analyze complex spatially developed processes in cases where it is impossible to determine the demarcated zones in the traditional way. The proposed method due to the universal simple principles can be expanded for analysis of any devices and processes with spatially developed configurations where approach of continuous medium is considered. The application of the proposed technology of metal refining in the tundish ladle of CCM which consists of a combination of purge modes, parameters of multichannel transverse bottom lance and geometric parameters of built-in elements, which shapes tundish metal flows, as well as positioning of lance and built-in elements, guarantee 2 times purification of cast metal from secondary non-metallic inclusions with almost complete removal of inclusions larger than 30 μm. Effectiveness of elements of proposed technology was tested experimentally in the conditions of PJSC MK "Azovstal" (Mariupol) during continuous casting of steel slabs of strength categories X60 and X70.