Numerical Analysis of the Influence of the Modification of the Ladle Shroud on Fluid Flow Behavior in a One-strand Tundish during Continuous Steel Casting

A tundish is a device from which liquid steel is pour into a mold. Therefore tundish hydrodynamic conditions have a significant impact on solidification during continuous steel casting (CSC) process. Modification of ladle shroud workspace, allows for the modification of liquid steel movement in the tundish. In the following work, numerical simulations were performed which allowed the impact of the modification of the ladle shroud workspace on the liquid steel flow structure in a one-strand tundish to be determined. In order to assess the impact of the modification of the ladle shroud on the behavior of the liquid steel in the tundish, simulations were performed, on the basis of which the percentage share of stagnant, ideal mixing and plug flow zones were determined. In addition, the mixing parameters were determined, allowing the estimation of casting duration during sequential casting. The flow fields of liquid steel for each modification of the ladle shroud were performed. The average velocity of liquid steel flowing through the tundish, the Reynolds number and turbulent intensity were also described. The obtained results showed, among others, that the application of three cylinders with a diameter of 0.041 m into the ladle shroud with a diameter of 0.11 m increases the share of active flow in the tundish in relation to the tundish with Conventional Ladle Shroud. At the same time, applying a ladle shroud with a diameter of 0.11 m during casting is the most favorable in relation to the hydrodynamics of the tundish.

Experience of thick-walled calcium-containing cored wire application at steel ladle treatment

Metal processing in ladle by calcium-containing cored wires is one of the most spread methods of ladle treatment and modifying. Results of analysis of efficiency induces of existing cored wires application depending on their diameter, wall thickness and filling coefficient presented. It was shown that the basic efficiency index of a cored wire application – recovery coefficient – depending on wire quality (homogeneity of filling by calcium along the wire length), wire grade, conditions of its injection into liquid steel and other parameters can vary within a range from 50 to 95%. Reasons of unsatisfactory calcium recovery at usage of calcium-containing wires of 14–15 mm diameter with steel shell 0.4 mm thick and filling of mechanical mixture of steel shots and metallic calcium in various proportions was considered. Advantages of the modern calcium-containing cored wire with thicker wall were highlighted, including their higher wire rigidity and stability of its supply by a wire feeder into liquid steel. It was established that calcium content in a cored wire at the level of 100 g/m was the most effective composition. It was noted that increase of speed of cored wire feeding into steel will result in an increase of calcium recovery and in a decrease of probability of metal splashing out the steel ladle.

Liquid Inclusion Collision and Agglomeration in Calcium-Treated Aluminum-Killed Steel

This work addresses conflicting results in the literature regarding liquid inclusion agglomeration. To assess whether liquid calcium aluminates do agglomerate in liquid steel, laboratory experiments were performed: melting electrolytic iron, deoxidizing the melt with aluminum and subsequently calcium treating the deoxidation products (alumina and magnesia-alumina spinel inclusions). Under laboratory conditions, solid spinels and alumina inclusions were successfully modified, producing a new population of much smaller calcium aluminate inclusions. The new population of inclusions forms because the presence of calcium in the liquid steel destabilizes alumina and MgO-alumina inclusions, which then dissolve into the melt. The liquid inclusions exhibited a weak but statistically significant tendency to agglomerate. Laboratory results were assessed in the light of different collision mechanisms. Agglomeration mainly occurs by Stokes and laminar fluid flow collision when no external stirring is imposed. Monte Carlo simulations of collisions agree reasonably well with experimental results. For industrial conditions, where the liquid steel is agitated by argon bubbling and/or electromagnetic stirring, turbulent collisions dominate.

Analysis of Non-Symmetrical Heat Removal during Cast-ing of Steel Billets and Slabs

Steel is one of the essential materials in the world's civilization. It is essential to produce many products such as pipelines, mechanical elements in machines, vehicles, profiles, and beam sections for buildings in many industries. Until the '50s of the 20th century, steel products required a complex process known as ingot casting; for years, steelmakers focused on developing and simplifying this process. The result was the con-tinuous casting process (CCP); it is the most productive method to produce steel. The CCP allows producing significant volumes of steel sections without interruption and is more productive than the formal ingot casting process. The CCP begins by transferring the liquid steel from the steel-ladle to a tundish. This tundish or vessel distributes the liquid steel, by flowing through its volume, to one or more strands having wa-ter-cooled copper molds. The mold is the primary cooling system, PCS, solidifying a steel shell to withstand a liquid core and its friction forces with the mold wall. Further down the mold, the rolls drive the steel section in the SCS. Here the steel section is cooled, solidifying the remaining liquid core, by sprays placed in every cooling segment all around the billet and along the curved section of the machine. Finally, the steel strand goes towards a horizontal-straight free-spray zone, losing heat by radiation mechanism, where the billet cools down further to total solidification. A moving torch cutting-scissor splits the billet to the desired length at the end of this heat-radiant zone.

Prospects for Using Alumina-Containing Industrial Waste in Cement Production

Local industrial waste from the Samara region (aluminochrome waste of petrochemicals, aluminium sludge of non-ferrous metallurgy) has been studied for use in the production of fire-resistant lining materials with enhanced operational characteristics. The composition and properties of industrial wastes formed at the Samara Metallurgical Plant and their application for obtaining active liquid-steel binder compositions have been studied. The dependence of these compositions refractoriness on the type of hardener and the amount of additive has been analyzed.