Wyniki wyszukiwania - BazTech

1

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

|

2019

|

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.

2

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

|

2018

|

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.

3

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

|

2017

|

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.

4

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

|

2017

|

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.

5

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

|

2016

|

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.

6

Influence of Direct Thermal Analysis Experimental Conditions on Determination of the High Temperature Phase Transformation Temperatures

Gryc K., Strouhalová M., Smetana B., Socha L., Michalek K.

Archives of Metallurgy and Materials

|

2015

|

Vol. 60, iss. 4

2867--2872

EN

Thermo-physical and thermodynamic properties of metallic systems represent some of the most important data that allows to describe their behaviour under strictly specified conditions. These data are the basic, input data for simulative programs, which can model this behaviour and they can be applied to real conditions. Method of direct thermal analysis is the one of the methods of enabling to obtain such data. This paper deals with application of this method on particular sample of pure standard material. The experimental laboratory system for thermal analysis Netzsch STA 449 F3 Jupiter was used for experimental measurements. This paper is studying the influence of experimental conditions on the obtained temperature of phase transformations and on shift of phase transformation temperatures with respect to the monitored experimental conditions, accuracy and credibility of the measured data. Acquired values of this data could be significantly influenced by experimental conditions, size (mass) of samples, purity of inert atmosphere and also by regimes of controlled heating and cooling rates.

PL

Właściwości fizyczne i termodynamiczne układów metalicznych stanowią jedne z najważniejszych danych, które pozwalają opisać ich zachowanie w ściśle określonych warunkach. Dane te są podstawowymi danymi wejściowymi dla programu, który może symulować model tych zachowań i które mogą być zastosowane do rzeczywistych warunków. Metoda prostej (bezpośredniej) analizy termicznej jest jedną z metod pozwalających na uzyskanie takich danych. Niniejszy artykuł dotyczy zastosowania tej metody, w szczególności próbki czystego materiału standardowego. Do pomiarów eksperymentalnych było używane urządzenie dla analizy termicznej Netzsch STA 449 F3 Jupiter. W artykule analizowano wpływ warunków doświadczalnych na uzyskane temperatury przemian fazowych oraz na zmiany temperatur przemian fazowych z uwzględnieniem monitorowanych warunków doświadczalnych, dokładności i wiarygodności danych pomiarowych. Warunki doświadczalne, wielkości (masa) próbek, czystość atmosfery obojętnej, a przedziały kontrolowanej szybkości ogrzewania i chłodzenia mogą w znaczący sposób wpływać na otrzymane wartości tych danych.

7

Evaluation of Influence of Briquetted Synthetic Slags on Slag Regime and Process of Steel Desulphurization

Socha L., Michalek K., Bažan J., Gryc K., Machovčák P., Opler A., Styrnal P.

Archives of Metallurgy and Materials

|

2014

|

Vol. 59, iss. 2

809--813

EN

This paper presents the industrial results of evaluation of efficiency of synthetic slags during the treatment of steel at the equipment of the secondary metallurgy under conditions of the steel plant VÍTKOVICE HEAVY MACHINERY a.s. The aim of the heats was to assess the influence of the briquetted and sintered synthetic slags based on AI2O3 aiming the course of the steel desulphurization and slag regime during the production and treatment of steel grade 42CrMo4 with the technology EAF→LF→ VD. Within the plant experiments, basic parameters influencing the steel desulphurization and slag regime were monitored: desulphurization degree, basicity, content of easily reducible oxides, proportion of CaO/AI2O3 and Mannesmann’s index. Obtained results allowed to compare the steel desulphurization and to evaluate the slag regime. It was proved that the synthetic slag presenting the briquetted mixture of secondary corundum raw materials can adequately replace the synthetic slag created from the sintered mixture of natural raw materials.

PL

W pracy tej przedstawiono przemysłowe wyniki oceny efektywności zastosowania żużli syntetycznych podczas obróbki pozapiecowej stali w zakładzie VÍTKOVlCE HEAVY MACHINERY a.s. Celem badań był a ocena wpływu brykietówanych i spiekanych żużli syntetycznych opartych na AI2O3 - na przebieg odsiarczania stali i żużla podczas produkcji i obróbki stali 42CrMo4. zgodnie z technologią EAF → LF → VD. Podczas eksperymentów w zakładzie, monitorowano podstawowe parametry wpływające na odsiarczania stali i żużla: stopień odsiarczania, zasadowość, zawartość tlenków łatwo redukowałnych, stosunek CaO/AI2O3 oraz indeks Mannesniann’a. Uzyskane wyniki pozwoliły na porównanie stopnia odsiarczania stali w kontekście zastosowanych żużli. Wykazano, że syntetyczny żużel składający się z brykietowanej mieszaniny wtórnego korundu, może zastąpić syntetyczny żużel otrzymywany ze spieku mieszaniny surowców naturalnych.

8

The effect of boundary conditions of casting on the size of porosity of heavy steel ingot

Tkadlečková M., Michalek K., Gryc K., Smetana B., Machovčák P., Socha L.

Journal of Achievements in Materials and Manufacturing Engineering

|

2013

|

Vol. 56, nr 1

29--37

EN

Purpose: The paper presents new knowledge from numerical modelling of porosity in heavy steel ingot using ProCAST software. The main aim of numerical modelling realized under the conditions of the Department of Metallurgy and Foundry and Regional Materials Science and Technology Centre at the VSB-TU Ostrava is the optimization of the production of heavy steel ingots produced at the companyVítkovice Heavy Machinery a.s. Design/methodology/approach: The selected method of numerical modelling enables 3D fully dimensional numerical simulation of steel casting and the subsequent solidification of steel with the possibility of prediction of ingot defects. Findings: The numerical modelling of casting and solidification of the 90 ton heavy steel ingot under different boundary conditions of the casting led to these main conclusions: In all simulated variants, the final character of solidification was very similar. The lowest level of porosities were achieved in the variant when we used the longer filling time together with decrease of casting temperatures. However, the tested adjustment of casting technology appeared to have only small impact on the resulting porosity. Practical implications: The change of geometry of the mould will have probably more effect on the character of the solidification than only the small changes of the casting parameters which are dependent on the steel grade. Originality/value: On the basis of applied research in close collaboration with industry companies, the obtained data can contribute significantly to optimization the operating conditions, thereby increasing the efficiency of the steelmaking technology and final quality of cast steel.

9

Numerical modelling of macrosegregation in heavy steel ingot

Tkadlečková M., Machovčák P., Gryc K., Michalek K., Klus P.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 1

171-177

EN

The paper presents new knowledge and experience from numerical modelling of macrosegregation in heavy steel ingot using ProCAST software. The main aim of numerical modelling realized under the conditions of the Department of Metallurgy and Foundry and Regional Materials Science and Technology Centre at VSB-TU Ostrava is the optimization of the production of heavy steel ingots produced in V´ITKOVICE HEAVY MACHINERY a.s. Input parameters of computation were determined by the real conditions of parallel experimental casting of a 90-ton steel ingot. The input data were also verified by thermal analysis and thermography measurement. The numerical results of macrosegregation were compared with the chemical analysis evaluated in a real ingot section. According to the comparison, attention will be focused next on determination of the effect of boundary conditions of filling and solidification of the ingot on the size of macrosegregation.

PL

W artykule przedstawiono doswiadczenia i nowe informacje uzyskane o procesie makrosegregacji w wielkogabarytowym wlewku stalowym przy pomocy modelowania numerycznego z uzyciem oprogramowania ProCast. Głównym celem badan o charakterze modelowania numerycznego prowadzonych na Wydziale Metalurgii i Odlewnictwa oraz w Regionalnym Centrum Technologii i Inzynierii Materiałowej VSB-TU Ostrava jest optymalizacja produkcji wielkogabarytowych wlewków stalowych produkowanych w VITKOVICE HEAVY MACHINERY a.s. Dane wejsciowe do obliczen zostały wyznaczone w oparciu o opracowana analize rzeczywistych warunków odlewania stacjonarnego 90-tonowego wlewka stalowego. Zostały one dodatkowo zweryfikowane poprzez analize termiczna i pomiary termograficzne. Wyniki obliczen numerycznych porównano z wynikami analizy chemicznej przeprowadzonej dla wlewka rzeczywistego. Uzyskane rezultaty upowazniaja do podjecia w dalszej czesci badan problematyki dotyczacej okreslenia wpływu warunków brzegowych napełniania wlewnicy i krzepniecia wlewka na wielkosc procesu makrosegregacji.

10

Influence of submerged entry nozzle on intermixed zone in round blooms with a diameter of 525 mm

Michalek K., Gryc K., Tkadlečková M., Morávka J., Huczala T., Bocek D., Horáková D.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 1

187-191

EN

This work compares the experimental results of nickel concentration measurements in the intermixed zone of the continuously cast round blooms with a diameter of 525 mm using two types of submerged entry nozzles (SEN) - a straight-through nozzle and one with 5-ports. Based on determination of the system and optical interface in the blooms a detailed study of concentration profiles on the bloom surface in a small radius area, on the right side and then also on a cross-section of the blooms, was carried out. The results were further analysed using approximation models, and were to be used to verify the proposed model for predicting intermixed zones for a continuous casting machine, developed based on the results of physical and numerical modelling.

PL

Praca przedstawia porównanie wyników pomiarów doświadczalnych stężenia niklu we wlewkach okrągłych o średnicy 525 mm odlewanych metodą COS z strefa przejściową, przy użyciu dwóch typów wylewów zanurzanych typu SEN - wylewu osiowego oraz promieniowego 5-strumieniowego. Pomiary wykonano na powierzchni wlewków oraz na ich przekroju poprzecznym przy użyciu metod optycznych. Analizę uzyskanych wyników pomiarów przeprowadzono wykorzystując modele aproksymujace. Uzyskane w ten sposób rezultaty wykorzystano do modernizacji opracowanego wcześniej w oparciu o rezultaty badan o charakterze modelowania fizycznego i numerycznego modelu do prognozowania wielkości strefy przejściowej dla badanego urządzenia do ciągłego odlewania stali.

11

Evaluation of the chemical composition and microcleanliness of the steel samples from the heavy forging ingot

Michalek K., Tkadlečková M., Gryc K., Machovčák P.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 4

1161--1167

EN

The paper presents new results obtained from the evaluation of the chemical composition, microcleanliness and structure of the 90-ton heavy ingot cast in two successive heats, in which the content of Cu and Ni was intentionally modified in order to assess the degree of mutual mixing of the two heats in the ingot volume during the steel casting and solidification. For determination of chemical composition, spectral analysis and LECO were used. Microcleanliness evaluation was carried out on a Hitachi microanalytical complex equipped with the energy-dispersive spectrometer Vantage. To assess the composition of oxide non-metallic inclusions ternary diagrams were used. Structure of the basic steel matrix was induced by etching. The evaluation showed that in the casting of two successive heats, a certain degree of inhomogeneity of chemical composition, especially in the lower part of the ingot can be assumed in case of different composition. A greater segregation of sulphur in the central top part of the ingot was also detected. However, microcleanliness of the entire ingot is in general very good with low proportions of non-metallic inclusions.

PL

W pracy tej przedstawiono, wyniki uzyskane z oceny składu chemicznego, czystości w skali mikro i struktury 90 tonowych wlewków odlanych w dwóch kolejnych sekwencjach, w których zawartości Cu i Ni celowo zmieniono, dla oceny stopnia wzajemnego mieszania się dwóch wytopów w objętości wlewka podczas odlewania i krzepnięcia stali. Dla określenia składu chemicznego zastosowano analizę spektralną i LECO. Badania mikroczystości przeprowadzono na zespole urządzeń do mikroanalizy Hitachi wyposażonym w spektrometr energii rozproszonej Vantage. Dla oceny składu tlenkowych wtrąceń niemetalicznych użyto trójskładnikowych układów równowagi. Struktura podstawowej osnowy stali została ujawniona za pomocą trawienia. Ocena wykazała, iż przy odlewaniu dwóch kolejnych odlewów, można zakładać pewien stopień niejednorodności składu chemicznego, zwłaszcza w dolnej części wlewka, zwłaszcza przy różnych składach chemicznych. Stwierdzono również większą segregację siarki w centralnej części wlewka Jednakże, mikroczystość całego wlewka jest na ogół bardzo dobra, przy niskich proporcjach wtrąceń niemetalicznych.

12

Study of Fe-C-based alloys by dynamic methods of thermal analysis

Gryc K., Smetana B., Žaludová M, Tkadlečková M., Michalek K., Socha L., Klus P., Dobrovská J., Machovčák P.

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 55, nr 2

694--699

EN

Purpose: of this paper is to determine the temperatures of liquidus/solidus temperatures for multicomponent Fe-C-based alloys (industrially produced steel grades). The obtained results could be used in settings of conditions of steel casting and/or in the numerical simulations of processes occurring during casting and solidification of steel. Design/methodology/approach: Two modern apparatus for dynamic thermal analysis were used. Measurements of liquidus/solidus temperatures were realized by two thermal analysis methods. Experiments by the differential scanning calorimetry were done using the new one Setaram Multi High Temperature Calorimeter with 3D sensor (smaller samples about 2.6 g). The direct thermal analysis was used for large samples (23 g) at the STA 449 F3 Jupiter equipment. Findings: The differences between calculated and experimentally obtained values of liquidus/solidus temperatures were found. Also temperatures of solidification process are different than for “equilibrium” conditions. Practical implications: Presented results will be implemented into steel production practice - lowering of superheating of steel during ingot casting. The obtained temperatures will be implemented also into numerical simulations of ingot solidification. Originality/value: Two thermal analysis methods with different sample mass of steel was used under conditions of one research team. The direct cooperation between steel plant experts and university research team was applied. The utilization of results is the next phases of cooperated research of the authors.

13

Modelling steel’s homogenization during argon purging

Pieprzyca J., Kudliński Z., Michalek K., Gryc K., Tkadlečková M.

Journal of Achievements in Materials and Manufacturing Engineering

|

2012

|

Vol. 55, nr 2

573--577

EN

Purpose: One of the primary tasks that put the steel producers to the test is to reduce production costs while maintaining high quality. This objective is achieved among others through the optimization of conducted technological processes. Commonly used technology of steel homogenization with inert gases is an important stage in the production of steel in which that objective can be accomplished. Design/methodology/approach: Tests of hydrodynamic processes occurring during the steel blowing with inert gases process directly in industrial conditions is very difficult or impossible. Therefore, as the primary research method physical modelling was used. In order to carry out the tests described in the article a physical model of the station for the argon purging was used that is working at the VSB-TU, Department of Metallurgy and Foundry in Ostrava. Findings: As a result the study provided values for the investigated process and determined the appropriate location of the gas-permeable fittings in steelmaking ladle’s bottom plug. This allows to obtain the required conditions for the steel mixing in the entire volume of ladle’s workspace. Research limitations/implications: Tests presented in the article were carried out in the VSB-TU in Ostrava. Due to this fact some research limitations occurs that applies to localization and physical model’s specific construction. Therefore, as a result of cooperation between VSB-TU in Ostrava and the Silesian University of Technology will be carried out the construction of the new research station in Katowice. Practical implications: The results of the research constitute the basis to make changes that will allow the optimization to so far used purge of steel technology. Originality/value: The results presented in the article are addressed to the steel producers and it allows to optimize on-going steel homogenization process that takes place in the ladle.

14

Model study of tundish steel intermixing and operational verification

Michalek K., Gryc K., Tkadleckova M., Bocek D.

Archives of Metallurgy and Materials

|

2012

|

Vol. 57, iss. 1

291-296

EN

The aim of this paper will be to present new knowledge and experience from numerical and physical modelling of metallurgical processes at the Department of Metallurgy, VSB - Technical University of Ostrava in Czech Republic and to explain especially the principle of tundish process simulations. The numerical modelling was realized by the CFD program FLUENT. The paper describes the pre-processing, processing and post-processing phases of numerical modelling. The physical modelling of the steel flow verification is based on a monitoring of the time dependency of concentration changes during experiments for individual tundish outlets. There exist two basic methods of KCl concentration change utilization in this "water" physical tundish modelling methodology. The utilization of mentioned methods are discussed and possible future developments are outlined for research of tundish steel intermixing.

PL

Celem artykułu jest przedstawienie wyników i doświadczeń z numerycznego i fizycznego modelowania procesów metalurgicznych w Zakładzie Metalurgii, VSB - Uniwersytet Techniczny w Ostrawie (Republika Czeska) i wyjaśnienie zasady symulacji procesów mieszania stali w kadzi pośredniej. Program CFD FLUENT posłużył do modelowania numerycznego. W artykule opisano pre-processing, processing i post-processing modelowania numerycznego. Weryfikację modelowania fizycznego przepływu stali dokonano w oparciu o eksperymenty, w których monitorowano zmianę stężenia w czasie dla poszczególnych stref kadzi. Istnieją dwie podstawowe metody wykorzystania zmian stężenia KCl w wodzie. Omówiono wykorzystanie wymienionych metod i możliwości przyszłego rozwoju badań mieszania stali w kadzi pośredniej.

15

Utilization of thermal analysis to thermo physical properties study of real steel grades

Klus P., Zaludova M, Gryc K., Smetana B., Michalek K., Dobrovska J., Tkadleckova M., Socha L.

Archives of Materials Science and Engineering

|

2012

|

Vol. 58, nr 2

116--119

EN

Purpose: This paper deals with determining the temperatures of phase transformations in real steel grades. It also includes the study of industrially produced steel grades using the methods of thermal analysis by experimental equipment STA 449 F3 Jupiter made by NETZSCH and Setsys 18TM made by SETARAM. Design/methodology/approach: Selected methods of thermal analysis (DSC and DTA) enable to obtain the temperatures of phase transformations taking place in steel during the linear heating/cooling. Within the casting technology of steel, thermal analysis is used to determine the solidus temperature and especially the crucial liquidus temperature. Findings: Experimentally obtained solidus and liquidus temperatures are higher in the DSC method (max. 3.8°C). The difference between the temperatures of phase transformation (T) running between the solidus temperature (TS) and liquidus (TL) for both methods (DTA and DSC) differ by a maximum of 3.2°C. The results from experimental measurements were compared with theoretical calculations of liquidus and solidus temperatures by different authors and with the computed results from thermodynamic database COMPUTHERM and also with temperatures from the equilibrium phase diagram of Fe-Cr-C. Experimentally obtained solidus temperatures are lower than the calculated equilibrium solidus temperatures. Experimentally obtained liquidus temperatures are in the range of temperatures obtained using computational relations. The temperatures mentioned in the equilibrium phase diagram (diagram for a particular steel grades was not found) are higher than experimentally obtained temperatures. Research limitations/implications: The results of experimental studies can be used to refine the knowledge of basic physical properties of steel and for example replacement of the tabulated values or estimated values of phase transformation temperatures and thermal capacity. Furthermore, the obtained data will be implemented in the material databases of numerical programs used for the simulation of metallurgical processes. Originality/value: On the basis of applied research in close collaboration with industry companies, the obtained data can contribute significantly to optimize the operating conditions, thereby increasing the efficiency of the steelmaking technology and final quality of cast steel.

16

Evaluation of slag regime in ladle during utilization of briquetted synthetic slag in VHM a.s.

Socha L., Bazan J., Gryc K., Machovcak P., Opler A., Trefil A., Melecky J.

Archives of Materials Science and Engineering

|

2012

|

Vol. 57, nr 2

80--87

EN

Purpose: The paper focuses on evaluation of slag regime by the help of synthetic slags based on Al2O3. The comparion of influence of synthetic slags on the production of two chosen grades of steels focused on evaluation of effectivity of created refining slag during treatment in the secondary metallurgy was the objective of plant experiments. Design/methodology/approach:During evaluation of slag regime in the ladle, steel samples for assessment of desulphurization degree were taken under the plant conditions. Slag samples were also taken for evaluation of chosen parameters: basicity, content of easily reducible oxides, proportion of CaO/Al2O3 and Mannesmann’s index. The temperature and oxygen activity in steel was continuously measured too. Findings: From plant experiments, it was found out that during using of two different types of synthetic slags during production of steel grades St52-3 and S34MnV similar values of desulphurization degree were achieved. Chosen parameters of ladle slag were monitored and it was demonstrated that the developed synthetic slag B reaches the results comparable with the standard used synthetic slag A. Research limitations/implications: Plant experiments were made under conditions of VÍTKOVICE HEAVY MACHINERY a.s. plant Obtained results are limited by the testing during production of two different steel grades St52-3, S34MnV and by the specific technology of production formed by EAF→LF→VD/VCD. Practical implications: The research results made it possible to realize the optimalization of slag regime under the plant conditions of VÍTKOVICE HEAVY MACHINERY a.s. plant. It was proved that developed synthetic slag B from the company JAP TRADING s.r.o. can adequately replace the common synthetic slag A. Originality/value:Results mentioned in this paper are intended for steel producers and they represent basic information about possibilities of slag regime optimalization in the ladle.

17

Modification of Slag in the Ladle by the Help of Briquetted Fluxing Agents

Socha L., Bazan J., Gryc K., Styrnal P., Pilka V., Piegza Z.

Hutnik, Wiadomości Hutnicze

|

2011

|

Vol. 78, nr 9

772--774

EN

The paper presents results of influence of thinner additions into the steelmaking slag on steel desulphurization in the ladle. Comparison of effectivity of two developed briquetted thinners based on Al2O3 with the thinner in common used at the steelworks Třinecké železárny, a.s. was made.

PL

W artykule przedstawiono wyniki badań wpływu dodatków upłynniacza żużla na odsiarczanie stali w kadzi stalowniczej. Przeprowadzono porównanie skuteczności dwóch rodzajów badanego, brykietowanego upłynniacza żużla na bazie Al2O3 z upłynniaczem powszechnie stosowanym w stalowni Třinecké železárny, a.s.

18

Physical Modelling of Metal Bath Flow in the Tundish and Importance of Validation Experiments

Michalek K., Hudzieczek Z., Gryc K., Moravka J., Pieprzyca J.

Hutnik, Wiadomości Hutnicze

|

2010

|

Vol. 77, nr 2

43-47

EN

Accuracy and thus the applicability of physical modelling results in the field of metallurgical processes must respect the basic rules of similarity theory and practice between the two systems. The choice of model geometry (length) scale is one of the basic factors which must be very carefully determined. This paper deals with the assessment of the impact of the geometric scale of the physical model of a tundish on the coincidence of the simulation results. Two models of an identical operating tundish designed on the scales 0.2 and 0.25 (1:5 and 1:4) were used for the experimental study. Different boundary conditions, including changes in the geometry of the bottom without any kind of impact pad (e.g. “Turbostop”) were used to study the correctness of the similarity theory between the two systems. Experiments were carried out and then compared from the perspective of permanent change (F-curve) of tracer (KCl) concentration. The results of experiments were processed by mathematical/statistical methods.

PL

Dokładność rezultatów uzyskiwanych w trakcie modelowania fizycznego procesów metalurgicznych i możliwość aplikowania ich do warunków rzeczywistych uzależniona jest od zastosowanych w modelach fizycznych kryteriów podobieństwa pomiędzy tymi dwoma układami. Wybór skali liniowej (geometria) jest jednym z fundamentalnych czynników, który musi być ściśle określony. W artykule przedstawiono porównanie wyników symulacji przeprowadzonych na modelach fizycznych kadzi pośredniej różniących się skalą liniową. Do badań użyto dwóch modeli fizycznych tej samej rzeczywistej kadzi pośredniej wykonanych w skali liniowej SL = 0,2 i SL = 0,25 (1:5 i 1:4). Dla weryfikacji warunków podobieństwa, badania przeprowadzono bez zabudowy modeli kadzi pośrednich w regulatory przepływu oraz z wykorzystaniem podstrumieniowego regulatora przepływu typu turbostop. Porównanie wyników badań przeprowadzono na podstawie wygenerowanych krzywych RTD (krzywa F), zmiany stężenia znacznika KCl. Wyniki eksperymentów były analizowane za pomocą metod statystycznych.

19

Fyzikální a numerické modelové studium charakteru proudění kovové taveniny v průtočném metalurgickém agregátu při různých okrajových podmínkách

Michalek K., Gryc K., Strasak P.

Prace Instytutu Metalurgii Żelaza

|

2009

|

T. 61, nr 5

98-101

EN

The paper is devoted to a study of metal melt flow pattern in the through-flow metallurgical aggregate (tundish) under different boundary conditions. For evaluating of flow conditions in the tundish a permanent concentration change (Heaviside unit step) was used. Experiments carried out by physical model in the geometric scale 1:5 to the real tundish and simultaneously carried out by numerical simulations was done for one type of impact pad design under isothermal flow conditions. Physical modelling was done by changing of KCl water solution concentration during experiments and by measuring of conductibility in the inlet and outlets areas (thermal and conductibility probes). Obtained data was recalculated based upon Freude’s criterion to the real tundish conditions. For mathematical identification of individual F-curves the authentic approximate method was used. Numerical modelling was realized by CFD program Fluent. Results obtained from both modelling methods are compared by defined dimensionless concentration value (0,1) under conditions of three different surface highs for three different casting speeds. It could be noted that results obtained from both modelling methods are comparable – the methodology is set correctly.