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1

Investigations of Dual Plug Argon Blowing for Efficient Mixing at Ladle Furnace Station

Warzecha Marek, Hutny A., Warzecha P., Kutyła Z., Merder T.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 2

561--572

EN

The article presents the results of model research concerning the change of technology of argon blowing into liquid steel at the ladle furnace, using the dual plug system. The results of numerical simulations were verified with experimental data carried out on the water model device. The verified model was used to perform numerical simulations to predict the impact of using a new gas injection technology - with different flow rates - on the time to achieve the assumed degree of metal chemical homogenization after alloy addition. Simulation results show that argon blowing metal bath in dual plug mode can effectively reduce mixing time compared to conventional technology with the same gas flow rates. Generally, the use of the dual plug system is beneficial for reducing the bath mixing time, however, the assumed optimal proportion of gas blown through individual plug should be followed. Finally, numerical predictions were used to perform experimental melt under industrial conditions. Industrial verification has clearly confirmed the validity of numerical modeling and showed that also in industrial conditions, a shorter time of chemical homogenization was obtained for the dual plug system.

2

The Influence of Parameters of Argon Purging Process Through Ladle on the Phenomena Occuring in the Area of Phase Distributions: Liquid Steal-Slag

Pieprzyca J., Merder T., Saternus M., Gryc K., Socha L.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

653--658

EN

Purging the liquid steel with inert gases is a commonly used treatment in secondary metallurgy. The main purposes for which this method is used are: homogenization of liquid steel in the entire volume of the ladle, improvement of mixing conditions, acceleration of the absorption process of alloy additives and refining of liquid steel from non-metallic inclusions. The basic processing parameters of this treatment are: gas flow rate and the level of gas dispersion in liquid steel. The level of gas dispersion depends on the design and location of the porous plug in the ladle. Therefore, these parameters have a significant impact on the phenomena occurring in the contact zone of liquid steel with slag. Their improper selection may cause secondary contamination of the bath with exogenous inclusions from the slag, or air atmosphere due to discontinuity of the slag and exposure of the excessive surface of the liquid steel free surface. The article presents the results of modelling research of the effect of liquid steel purging with inert gases on phenomena occurring in this zone. The research was carried out using the physical (water) model of steel ladle. As a modelling liquid representing slag, paraffin oil was used, taking into account the conditions of similarity with particular reference to the kinematic viscosity. The results of the conducted research were presented in the form of visualization of phenomena occurring on the surface of the model liquid free surface in the form of photographs. The work is a part of a bigger study concerning modelling of ladle processes.

3

Numerical Modelling of Metal Melt Refining Process in Ladle with Rotating Impeller and Breakwaters

Sviželová J., Tkadlečková M., Michalek K., Walek J., Saternus M., Pieprzyca J., Merder T.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 2

659--664

EN

The paper describes research and development of aluminium melt refining technology in a ladle with rotating impeller and breakwaters using numerical modelling of a finite volume/element method. The theoretical aspects of refining technology are outlined. The design of the numerical model is described and discussed. The differences between real process conditions and numerical model limitations are mentioned. Based on the hypothesis and the results of numerical modelling, the most appropriate setting of the numerical model is recommended. Also, the possibilities of monitoring of degassing are explained. The results of numerical modelling allow to improve the refining technology of metal melts and to control the final quality under different boundary conditions, such as rotating speed, shape and position of rotating impeller, breakwaters and intensity of inert gas blowing through the impeller.

4

Hydrodynamic conditions of flow in the tundish depending on selected technological parameters for different steel groups

Warzecha M., Merder T., Warzecha P., Hutny A. M.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 1

65--70

EN

The presented results of investigations are part of a larger study focused on the optimization of the flow and mixing of liquid steel in the industrial tundish of continuous casting machine. The numerical simulations were carried out concern the analysis of hydrodynamic conditions of liquid steel flow in a tundish operating in one of the national steelworks. Numerical simulations were performed using the commercial code ANSYS Fluent. The research concerns two different speeds of steel casting. In real conditions, these speeds are the most commonly used in the technological process when casting two different groups of steel. As a result of computational fluid dynamics (CFD) calculations, predicted spatial distributions of velocity and liquid steel turbulence fields and residence time distribution (RTD) curves were obtained. The volume fractions of different flows occurring in the tundish were also calculated. The results of the research allowed a detailed analysis of the influence of casting speed on the formation of hydrodynamic conditions prevailing in the reactor.

5

Physical Modelling of Degassing Process by Blowing of Inert Gas

Michalek K., Tkadlečková M., Socha L., Gryc K., Saternus M., Pieprzyca J., Merder T.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

987--992

EN

This paper deals with the possibilities of using physical modelling to study the degassing of metal melt during its treatment in the refining ladle. The method of inert gas blowing, so-called refining gas, presents the most common operational technology for the elimination of impurities from molten metal, e.g. for decreasing or removing the hydrogen content from liquid aluminium. This refining process presents the system of gas-liquid and its efficiency depends on the creation of fine bubbles with a high interphase surface, uniform distribution, long period of its effect in the melt, and mostly on the uniform arrangement of bubbles into the whole volume of the refining ladle. Physical modelling represents the basic method of modelling and it makes it possible to obtain information about the course of refining processes. On the basis of obtained results, it is possible to predict the behaviour of the real system during different changes in the process. The experimental part focuses on the evaluation of methodical laboratory experiments aimed at the proposal and testing of the developed methods of degassing during physical modelling. The results obtained on the basis of laboratory experiments realized on the specific physical model were discussed.

6

Numerical Analysis of the Structure of Liquid Flow in the Tundish with Physical Model Verification

Merder T.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 4

1895--1901

EN

Detailed studies of the movement of liquid steel (hydrodynamics) on a real object are practically impossible. The solution to this problem are physical modelling carried out on water models and numerical modelling using appropriate programs. The method of numerical modelling thanks to the considerable computing power of modern computers gives the possibility of solving very complex problems. The paper presents the results of model tests of liquid flow through tundish. The examined object was model of the twonozzle tundish model. The ANSYS Fluent program was used to describe the behavior of liquid in the working area of the tundish model. Numerical simulations were carried out using two numerical methods of turbulence description: RANS (Reynolds-Averaged Navier-Stokes) – model k-ε and LES (Large Eddy Simulation). The results obtained from CFD calculations were compared with the results obtained using the water model.

7

Evaluation of Approaches of Numerical Modelling of Solidification of Continuously Cast Steel Billets

Tkadlečková M., Michalek K., Strouhalová M., Sviželová J., Saternus M., Pieprzyca J., Merder T.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

1003--1008

EN

The paper evaluates two approaches of numerical modelling of solidification of continuously cast steel billets by finite element method, namely by the numerical modelling under the Steady-State Thermal Conditions, and by the numerical modelling with the Traveling Boundary Conditions. In the paper, the 3D drawing of the geometry, the preparation of computational mesh, the definition of boundary conditions and also the definition of thermo-physical properties of materials in relation to the expected results are discussed. The effect of thermo-physical properties on the computation of central porosity in billet is also mentioned. In conclusion, the advantages and disadvantages of two described approaches are listed and the direction of the next research in the prediction of temperature field in continuously cast billets is also outlined.

8

Badania wpływu konstrukcji wirnika urządzenia do rafinacji okresowej aluminium na hydrodynamikę procesu

Saternus M., Szudy R., Róg M., Pieprzyca J., Merder T.

Rudy i Metale Nieżelazne Recykling

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2017

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R. 62, nr 4

9--15

PL

W pracy przedstawiono wyniki badań przeprowadzonych z wykorzystaniem modelu fizycznego reaktora do rafinacji okresowej aluminium metodą barbotażu. Skupiono się głównie na konstrukcji wirnika doprowadzającego gaz rafinujący do ciekłego metalu. Zaprojektowano dwa różne rodzaje wirników, które następnie zostały wydrukowane przy użyciu drukarki 3D. Konstrukcja wirnika oraz dobór odpowiednich parametrów procesowych, mają duży wpływ na pożądany, równomierny poziom dyspersji pęcherzyków gazowych w metalu. Badania przeprowadzono dla natężenia przepływu gazu od 10 do 30 dm3/min oraz prędkości obrotowej rotora od 240 do 400 obr./min. Na podstawie wyników testów wyznaczono krzywe RTD, umożliwiające określenie minimalnego czasu mieszania znacznika w cieczy modelowej dla obu testowanych wirników. Przeprowadzono również badania wizualizacji stopnia dyspersji pęcherzyków gazowych w objętości reaktora.

EN

Results of research conducted with the use of physical model of reactor applied for batch aluminium refining process by barbotage method were presented and discussed. The main focus was put on the construction of rotary impeller, which introduces the refining gas into the liquid metal. Two different rotary impellers were designed, which consequently were printed using 3D printer. The impeller construction and the choice of appropriate processing parameters influence greatly on the desirable uniform level of gas dispersion in the metal. The research was carried out for the flow rate of refining gas from 10 to 30 dm3/min and the rotary impeller speed from 240 to 400 rpm. Basing on the tests results the RTD curves were deter¬mined, which give the possibility to estimate the minimal time of mixing the tracer in the modelling liquid for both types of impellers. Additionally the research of visualization of the gas bubbles dispersion in the reactor volume was also conducted.

9

Research and Development of the Solidification of Slab Ingots from Special Tool Steels

Tkadlečková M., Michalek K., Gryc K., Socha L., Jonšta P., Saternus M., Pieprzyca J., Merder T.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1453--1458

EN

The paper describes the research and development of casting and solidification of slab ingots from special tool steels by means of numerical modelling using the finite element method. The pre-processing, processing and post-processing phases of numerical modelling are outlined. Also, problems with determining the thermophysical properties of materials and heat transfer between the individual parts of the casting system are discussed. Based on the type of grade of tool steel, the risk of final porosity is predicted. The results allowed to improve the production technology of slab ingots, and also to verify the ratio, the chamfer and the external/ internal shape of the wall of the new designed slab ingots.

10

Physical Modelling of Tundish Slag Entrainment under Various Technological Conditions

Michalek K., Gryc K., Socha L., Tkadlečková M., Saternus M., Pieprzyca J., Merder T., Pindor L.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 3

1467--1471

EN

This paper deals with the issue of physical modelling of vortexes creation and tundish slag entrainment over the mouth of the nozzle into the individual casting strands. Proper physical model is equivalent to the operational continuous casting machine No. 2 in TŘINECKÉ ŽELEZÁRNY, a.s. Physical modelling methodology and simulated operational conditions are shortly described. Physical modelling was used for the evaluation of current conditions of steel casting at the application of different impact pads in the tundish. Further, laboratory measurement on the physical model aiming the determination of exact critical periods of vortexes creation and study of the slag entrainment as a consequence of changes in surface level during the tundish refilling to standard level were realised. The obtained results were analysed and discussed.

11

Application of High Flow Rate Gas in the Process of Argon Blowing Trough Steel

Merder T., Pieprzyca J., Warzecha M., Warzecha P.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2A

905--910

EN

The article demonstrates results of modelling research tests concerning the analysis of possibilities of blowing gas into the metal bath at high flow rates in a steel ladle with a nominal capacity of 50 Mg. Various configurations concerning of gas introduction into the steel ladle were analysed. There were considered cases of blowing into the metal bath via one, two or three purging plugs, being installed on the bottom and via additional support for blowing the gas from the top through the lance. Results obtained from the water model of the reactor were verified with the results of numerical simulations.

12

Wpływ typu kształtki gazoprzepuszczalnej na dyspersję gazu w kąpieli stalowej

Merder T., Warzecha P., Warzecha M., Pieprzyca J., Moycho J.

Hutnik, Wiadomości Hutnicze

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2016

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Vol. 83, nr 11

501--503

PL

W pracy przedstawiono wyniki symulacji numerycznych przepływu dwufazowego gaz-ciekła stal z wykorzystaniem modelu DiscretePhase Model (DPM). Testowano różne warunki początkowe i brzegowe wprowadzania gazu do cieczy. Szczegółowo analizowano dwa warianty sposobu wprowadzania argonu, w pierwszym wydostaje się on przez zdefiniowaną grupę punktów dyskretnych na powierzchni kształtki, a w drugim przez osiem szczelin zdefiniowanych na powierzchni kształtki. Prezentowane wyniki badań stanowią jeden z etapów hybrydowych badań modelowych związanych z opracowaniem nowatorskiej technologii przetwarzania złomu, pochodzącego z kordu opon samochodowych, poprzez jego roztopienie w piecu indukcyjnym i dalszą obróbkę w kadzi stalowniczej.

EN

Paper presents the results of numericalsimulations of two-phase flow (gas-liquid steel) using a DiscretePhase Model (DPM). Differentinitial and boundary conditions of introducing of gas into the liquid were tested. A detailedanalysis was performed for twospecificvariants of introducing argon: in a firstcase - gasisintroduced via defined group of discrete points on the porous plug surface, and in a second case; gas was introduced via eight slits defined at the plug surface. The results of presented research represent one of the stages of the hybrid modeling studies, related to the development of an innovative technologies of processing of scrap originating from the cord tires by melting it in induction furnace and further processing in the ladle.

13

Przedmuchiwanie ciekłej stali w kadzi przy dużych natężeniach przepływu gazu – modelowanie fizyczne

Pieprzyca J., Merder T., Warzecha M., Zdonek B., Bielański L.

Hutnik, Wiadomości Hutnicze

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2016

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Vol. 83, nr 11

498--500

PL

W pracy przedstawiono wyniki pilotażowych badań modelowych, przedmuchiwania ciekłej stali przy dużych natężeniach przepływu gazu. Przeprowadzone doświadczenia miały na celu określenie warunków hydrodynamicznych panujących w kadzi stalowniczej podczas procesu głębokiego odwęglania ciekłej stali tlenem wdmuchiwanym przez kształtkę gazoprzepuszczalną typu szczelinowego. Tego rodzaju zabiegi stosowane są jako innowacyjne rozwiązania przy utylizacji kordów z zużytych opon samochodowych i wytapianiu stali niskostopowych z bardzo niskimi zawartościami węgla. Może to mieć w przyszłości podstawowe znaczenie w produkcji stali o wysokich właściwościach mechanicznych i antykorozyjnych. Badania przeprowadzono na specjalnie w tym celu skonstruowanym i zbudowanym w skali liniowej SL = 0,25 modelu wodnym.

EN

The paper presents the results of a pilot model testing, purging the liquid steel at high gas flow rates. Experiments were designed to determine the hydrodynamic conditions prevailing in the tank during the deep decarburization of liquid steel oxygen blown through the gas-permeable type fitting slot. This kind of treatments are used as innovative solutions at the disposal of cords used car tires and smelting low alloy steels with very low carbon contents. This may be of fundamental importance in the production of ordinary steel with high mechanical properties and anti-corrosion. Tests were performed on a specially constructed and built in the linear model SL = 0.25 aq.

14

Analiza wpływu zastosowanego modelu matematycznego na prognozowaną dyspersję gazu w kąpieli stalowej

Warzecha M., Warzecha P., Merder T., Pieprzyca J., Mazurkiewicz J.

Hutnik, Wiadomości Hutnicze

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2016

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Vol. 83, nr 11

487--490

PL

W artykule przedstawiono wyniki badań CFD, które są częścią badań modelowych dotyczących opracowania nowatorskiej technologii przetwarzania złomu, pochodzącego z kordu opon samochodowych. Wyniki badań zawarte w niniejszej pracy dotyczą symulacji CFD przepływu dwufazowego gaz-ciekła stal, z wykorzystaniem dwóch różnych modeli matematycznych: Discrete Phase Model (DPM) oraz Volume of Fluid (VOF). W obliczeniach wykorzystano komercyjny program ANSYS Fluent. Analizowano odwzorowanie kolumny gazowo-cieczowej poprzez oba modele.

EN

The article presents the results of the CFD calculations, which are the part of the modeling studies, related to the development of an innovative technologies of processing of scrap originating from the cord tires. The test results presented in this paper apply to CFD simulation of two-phase (gas-liquid steel) plume, using two different mathematical models: Discrete Phase Model (DPM) and Volume of Fluid (VOF). The commercial computing program Ansys Fluent was used to perform calculations. The projection of gas-liquid plume by both models was analyzed.

15

Study of Tundish Slag Entrainment Using Physical Modelling

Michalek K., Gryc K., Socha L., Saternus M., Tkadlečková M., Pieprzyca J., Merder T., Pindor L.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

257--260

EN

This paper deals with the possibilities of using physical modelling to study the slag entrainment in the tundish. A level of steel in the tundish is changing during sequential continuous casting. The most significant decrease in the steel level occurs when replacing ladles. It is generally known that if the height of steel level in the tundish drops below a certain critical level, it may generate vortexes over the nozzles and as a consequence entrainment of tundish slag into individual casting strands can occur. Thus, it is necessary to identify the critical level of steel for specific operational conditions. In this paper, the development of physical modelling methodology is described as well as physical model corresponding to operational continuous casting machine No. 2 in Třinecké železárny, a.s. The obtained results are discussed.

16

Study of Solidification of Continuously Cast Steel Round Billets Using Numerical Modellin

Tkadleckova M., Válek L., Socha L., Saternus M., Pieprzyca J., Merder T., Michalek K., Kováč M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

221--226

EN

The paper is dedicated to the verification of solidification of continuously cast round steel billets using numerical modelling based on the finite element method. The aim of numerical modelling is to optimize the production of continuously cast steel billets of round format. The paper describes the pre-processing, processing and post-processing phases of numerical modelling. Also, the problems with determination of the thermodynamic properties of materials and the heat transfer between the individual parts of the casting system, including the definition of the heat losses along the casting strand in the primary and secondary cooling, were discussed. The first results of numerical simulation show the so-called thermal steady state of continuous casting. The temperature field, the metallurgical length and the thickness of the shell at the end of the mould were predicted. The further research will be concentrated on the prediction the risk of the cracks and the porosity based on the different boundary conditions.

17

Optimization of Steel Flow in the Tundish by Modifying its Working Area

Warzecha P., Hutny A. M., Warzecha M., Merder T.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

2071--2078

EN

Presented paper describes model investigations carried out on six-strand continuous casting tundish. Numerical analysis is based on simulations performed with the use of commercial code ANSYS Fluent. The analysis concerns determination of hydrodynamic conditions of the flow in the analysed tundish, with nominal capacity of 22 Mg, and its optimisation by modification of the flow structure in the tundish working area. Four different flow control devices (FCD) were proposed. Results of investigations presented in the paper include the distribution of velocity vectors and distribution of temperature and turbulence kinetic energy. Additionally, for more detailed comparative analysis, the macroscopic characteristics of residence time distribution (RTD) in the reactor, and the transition zone ranges were determined for each of the variants.

18

Identification of Relevant Work Parameters of Ladle Furnace While Melting the High Ductility Steel and High-Carbon Steel

Warzecha M., Garncarek S., Merder T., Skuza Z.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 1

275--278

EN

In the present paper, secondary metallurgical treatment in ladle furnace during smelting the high carbon steel and steel with improved ductility for cold-deforming, under industrial conditions were analyzed. Common features of these steels are high requirements/strict standards imposed for their metallurgical purity; however they are especially exorbitant for improved ductility steels. In addition, it is widely used to specify alloying additives having significant weights- such as carbon and manganese - and explicitly restricted content of nitrogen requiring metal bath cover prior nitriding.

19

Experimental Methods of Validation for Numerical Simulation Results on Steel Flow through Tundish

Pieprzyca J., Warzecha P., Merder T., Warzecha M.

Archives of Metallurgy and Materials

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2016

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Vol. 61, iss. 4

2057--2060

EN

The article presents experimental results on the impact of tundish flow regulator influencing the liquid steel flow course. The research was conducted based on the hybrid modelling methods understood as a complementary use of Computational Fluid Dynamics (CFD) methods and physical modelling. Dynamic development of numerical simulation techniques and accessibility to highly advanced and specialized software causes the fact that these techniques are commonly used for solving problems related to liquid flows by using analytical methods. Whereas, physical modelling is an important cognitive tool in the field of empirical identification of these phenomena. This allows for peer review and specification of the researched problems. By exploiting these relationships, a comparison of the obtained results was performed in the form of residence time distribution (RTD) curves and visualization of particular types of liquid steel flow distribution zones in the investigated tundish.

20

Badania modelowe homogenizacji stali przy różnych natężeniach przepływu strumienia gazu w kadzi stalowniczej

Sojda P., Warzecha M., Merder T., Olawa M., Jochymczyk D.

Hutnik, Wiadomości Hutnicze

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2015

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Vol. 82, nr 5

320--324

PL

Argonowanie, jako proces mieszania kąpieli metalowej, w kadziach stalowniczych stał się jednym z najczęściej stosowanych zabiegów technologicznych rafinacji. Zrozumienie i identyfikacja zjawisk hydrodynamicznych zachodzących w trakcie tego procesu umożliwia wyznaczanie optymalnych parametrów procesu. W tym celu zbudowano model wodny kadzi stalowniczej na Politechnice Śląskiej w Katowicach. Model ten jest zbudowany na podstawie doboru odpowiednich fizycznych kryteriów podobieństwa pomiędzy obiektem rzeczywistym a modelem wodnym. W artykule przedstawiono analizę stopnia homogenizacji stali w zależności od prędkości iniekcji gazu.

EN

Argon, as the melt mixing process, the steel ladle has become one of the most commonly used treatments refining technology. Understanding and identification of hydrodynamic phenomena occurring during this process enables us to determine the optimal process parameters dependent stsowanych permeable gas fittings. To this end, the model of iron and steel ladle water at Silesian University in Katowice. This model is built based on the selection criteria for adequate physical similarities between the real object and the model of water. The article presents an analysis of the degree of homogenization of steel depending on the speed of gas injection.