Browsing by Subject "continuous casting"

Now showing 1 - 4 of 4

Access status: Open Access ,
Mathematical modelling of the continuous casting of blooms and beam blanks
(Wydawnictwa AGH, 2021) Gomes, Daniela Fátima; Braga, Bernardo Martins; Tavares, Roberto Parreiras; Bagatini, Maurício Covcevich
Defects and discontinuities generated in continuous casting are directly related to heat transfer during the process and the stresses to which the material is subjected. Knowledge of these phenomena is essential for both process safety and the quality of the final product. The aim of this work is to analyze the thermo-mechanical behavior of blooms and beam blanks during continuous casting. The continuous casting machine considered in this study is used to cast both blooms and beam blanks. The secondary cooling can be divided into cooling zone z0, cooling zone z1, cooling zone z2, and cooling zone z3. For each geometry, there are specific molds, z0, z1, z2 (sprays and support rollers), which need to be replaced when there is a geometry shift. The changing of the cooling segments brings security risks for the operators and reduces the continuous casting availability. Therefore, it is desired to have a common z2 for both blooms and beam blanks to reduce operational risk exposure and increase the machine production rate. For this to be possible, it is necessary to assess the temperature and resistance of the solidified skin, the effects of thermal stresses, ferrostatic pressure, and contact stresses. This work is the first step in this study. A thermo-mechanical model was developed for both geometries. The thermal model was verified by temperature measurement and shell measurements of blackouts. Finally, the results were analyzed and compared.
Access status: Open Access ,
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
(AGH University of Science and Technology Press, 2021) Suchan, Hanna; Cwudziński, Adam
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.
Access status: Open Access ,
Research on mechanical and electrical properties of Cu-Ag alloys designed for the construction of high magnetic field generators
(AGH University of Science and Technology Press, 2021) Kawecki, Artur; Sieja-Smaga, Eliza; Korzeń, Kinga; Majchrowska, Magdalena; Noga, Piotr
The individual sections, wiring and construction of electromagnet windings responsible for strong magnetic field impulses may be one application for hypoeutectic Cu-Ag alloys. High electrical properties and mechanical properties (tensile strength, yield strength, impact strength) as well as high heat, fatigue and rheological resistance are required for these kinds of applications due to the unique nature of such operations (strong vibrations of high frequency and amplitude resulting from Lorenz forces and the possibility of significant and rapid heating from Jule's heat). The limited solubility of copper and silver in the solid state enables the effective modification of the alloys' microstructure through heat treatment and further shaping of their high mechanical and electrical properties via cold plastic working. The article presents the manufacturing of Cu-Ag alloys with the weight percent of Ag between 3 and 7 using the continuous casting process along with research on the physicochemical, mechanical and electrical properties of the obtained casts. The research on the amount of plastic deformation and its influence on the wire drawing process and the mechanical and electrical properties of the wires is also discussed. The temperature coefficients of resistance were defined in order to determine the temperature influence on the electrical resistance changes dynamics. The microstructural analysis was carried out in the as-cast state. The preliminary research conducted indicates that the obtained Cu-Ag alloys in the as-cast state exhibit a set of high mechanical and electrical properties. The prospective next stage of research includes the selection of favourable heat treatment parameters which would provide optimally modified microstructure of the alloys, as well as determining the deformation coefficients allowing for further increases in the mechanical and electrical properties.
Access status: Open Access ,
Research on new Al-Ag-Mo alloys dedicated to wire applications in overhead power lines
(AGH University Press, 2023) Grzebinoga, Justyna; Mamala, Andrzej; Ściężor, Wojciech; Kowal, Radosław
The latest research work in the field of electric power systems focuses on the development of new wire materials which will allow the increase of the transmission capacity of power lines currently in use. The reason for this research was the often limited possibilities of continuous and failure-free transmission of electricity. In this paper, the authors present research on a new aluminium-based alloy dedicated for use as a conductive braid in the HTLS cable group. There are many technical solutions for this group of cables on the market, although they are solutions with a number of disadvantages, ranging from their high price, various operational shortcomings, complicated installation techniques, and ending with the risk of monopolistic practices, which is related to the inability to attract several competitive suppliers. The main aim of the research was to develop a new alloy based on aluminium with the addition of silver and molybdenum dedicated for use in special overhead power cables. Experimental research on new materials focused on obtaining the necessary knowledge to produce an overhead wire from these alloys with higher current carrying capacity in relation to the currently used conventional wire materials based on aluminium.