The dissertation is devoted to the study of the processes of leakage of metal at the stage of the second technological transfusion of steel on CCM between the tundish and the mold, as well as methods for increasing the operating resource of submerged entry nozzle and improving the quality of the continuous casting slabs. By the experimental way, the regularities of leakage of metal on the site "tundish - mold" were determined for various designs of submerged entry nozzle when changing the width of the slab, the depth of location of the submerged entry nozzle, the amount of argon deposited into the submerged entry nozzle angle of opening of the side apertures. It wass shown that when injected with argon through a stopper, the injected gas is located mainly in the internal zones of the jet and moves at the speed of the liquid stream without disturbing its natural configuration. Injection of argon reduces the formation of slag-metal deposits. The greatest positive effect is achieved with argon consumption at the level of 5-8 l / min. At a higher cost of argon, an increase in the rate of overgrowth of the cavity of the submerged entry nozzle is observed, which is due to the spatter of the jet and the intense sticking of the droplets of steel on its inner surface. The rational size of the opening angle of the jet, which flows into the mold of the thick-slab CCM, is 10-15o, which can be used during the pouring of slabs of various geometric sizes, including the width. When choosing the optimal opening angle of the submerged entry nozzle, some correction in the direction of reducing the opening angle (about 5-8o) may be recommended, which takes into account the effect on the flowing streams of the upper circulating streams. In addition to the angle of opening of the outlets on the processes of overgrowing significantly affected area exhaust. Thus, the use of submerged entry nozzle with a large inefficient area of exhaust fumes entails accelerating processes of overgrowing due to the higher intensity of the return circulating flows from the mold. We received further development of the understanding of the nature of the mixing of metal and slag in the liquid bath of the mold with the asymmetric nature of the supply of metal. It was established that overgrowth of the inner cavity of the submerged entry nozzle a violation of the normal hydrodynamic picture of the distribution of steel fluxes in the mold, which in turn contributes to the development of vortex and wave processes. The fluctuation velocity on the surface of the meniscus of 40-50 mm should be considered critical, which leads to the stopping of the CCM or to the accident due to the breakthrough of the firm cinnamon. In the course of the development of standing waves, liquid casting powder is distributed along the mirror of the metal very unevenly and accumulates in the formed basins. It is noted that the uneven distribution of the casting powder is dangerous in terms of the formation of a firm cinnamon, because the thick layer of the casting powder reduces the intensity of the heat transfer and, consequently, the rate of crystallization, which can lead to the microstructures of the firm cinnamon directly in the mold due to its insufficient thickness and strength. In the p rocess of industrial tests, the mechanism for the formation of inclusions in the cavity of a the submerged entry nozzle was first studied. These inclusions consist of a mechanical mixture of alumina and droplets of steel. It has been established that the mass fraction of metallic impregnations varies within the limits of 65-90% of the total mass of the inclusions. Small metal particles (<1.5 - 2.0 mm) predominate in the sediments with a configuration close to spherical. Larger metal particles are inclusions of irregular shape and are conglomerates of several coalesced particles on a substrate from a nonmetallic part of the inclusions. The proportion of large metal particles (more than 7-8 mm) is 45-50% of the total mass of metallic particles entering the sediments.
