Wyniki wyszukiwania - Biblioteka Nauki

1

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

100%

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

Archives of Metallurgy and Materials

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2017

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tom 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.

2

Physical modelling of electromagnetic field of auroral electrojet

100%

Kobzova V. , Ladanivskyy B. , Korepanov V.

Acta Geophysica Polonica

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2003

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tom Vol. 51, nr 3

337-345

EN

The physical modeling method was to investigate the electromagnetic field of a source imitating the ionospheric electrojet on the surface of three-layer horizontally-homogeneous medium which models the Earth's deep section. Magnetotelluric sounding curves and the spataial structure of electromagnetic field components of the auroral source scale model were estimated. A comparison of the results with those obtained in plane homogenous field and in the field of vertical magnetic dipole located at some altitude above the surface of physical model revealed the following regularities. In the electrojet model field, some specific areas are distinguish with the different types of apperent resistivity curves: over a small area under the center of electrojet, the curves of apparent resistivity are identical with thise of the magnetic dipole; over a great territory under the electrojet, the results of MT sounding are similar to those obtained in the field of a plane homogeneous wave; under the edges of electrojet, substantial deviations from the plane homogeneous source are observed.

3

Determination of RTD Curves for Aluminium Refining Process Conducted in Batch Reactor – Physical Modelling

100%

Saternus M.

Archives of Metallurgy and Materials

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2018

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tom Vol. 63, iss. 4

1909--1914

EN

It is really hard to determine the phenomena occurring during aluminum refining process using argon blowing through the liquid metal in industrial conditions. The solution of such problem is physical modelling. This kind of modelling gives possibility to determine the level of dispersion of the refining gas in liquid metal. Especially in steel metallurgy RTD (Residence Time Distribution) analysis and visualization process with some colour tracer, which can give extra information about time of mixing are very popularly used. Because the modelling research (especially visualization) is pictorial, the research was conducted to check if it is possible to estimate quantitatively impeller working effectiveness basing on determination of the RTD curves. The examined object was model of URO-200 batch refining reactor. The RTD curves was registered and discussed for three different impellers and four different variants of processing parameters (rotary impeller speed: 300-500 rpm, and gas flow rate: 15-20 l·min-1). Additionally, the process of mixing of the inert gas with water as a modelling agent was enabled to be observed due to introduction of colour tracer (KMnO4). Results obtained from both measuring methods were graphically presented, compared and shortly discussed.

4

Określenie możliwości zastosowania nowego opisu matematycznego warunku podobieństwa plastycznego materiału w modelowaniu fizycznym procesów kształtowania plastycznego

100%

Gronostajski Z. , Hawryluk M.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2005

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tom z. 207

115--120

PL

W pracy zaproponowano nowe podejście do warunku podobieństwa plastycznego, w którym przyjmuje się ilościową ocenę kształtu krzywych naprężenie uplastyczniające-odkształcenie. Nowy opis warunku został zastosowany do modelowania fizycznego dwóch wybranych procesów.

EN

In the paper the new concept of plastic similarity condition in physical modeling of metal forming processes is proposed. New condition was applied to physical modeling of two chosen processes.

5

Development of an Approximation Model of Selected Properties of Model Materials Used for Simulations of Bulk Metal Plastic Forming Processes Using Induction of Decision Trees

100%

Hawryluk M. , Wilk-Kołodziejczyk D. , Regulski K. , Głowacki M.

Archives of Metallurgy and Materials

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2019

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tom Vol. 64, iss. 3

1073--1085

EN

The article discusses the development of an approximation model of selected plastic and mechanical properties obtained from compression tests of model materials used in physical modeling. The use of physical modeling with the use of soft model materials such as a synthetic wax branch with various modifiers is a popular tool used as an alternative or verification of numerical modeling of bulk metal forming processes. In order to develop an algorithm to facilitate the choice of material model to simulate the behavior of real-metallic materials used in industrial production processes the induction of decision trees was used. First of all, the Statistica program was used for data mining, which made it possible to determine / find the relationship between the percentage of particular constituents of the model material (base material and modifiers) and yield strength, critical and maximum strain, and provide the opportunity to indicate the most important variables determining the shape of the stress - strain curve. Next, using the induction of decision trees, an approximation model was developed, which allowed to create an algorithm facilitating the selection of individual modifying components. The last stage of the research was verification of the correctness of the developed algorithm. The obtained research results indicate the possibility of using decision tree induction to approximate selected properties of modeling materials simulating the behavior of real materials, thus eliminating the need for costly and time-consuming experiments carried out on metallic material.

6

Influence of impeller shape on the gas bubbles dispersion in aluminium refining process

100%

Saternus M.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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tom Vol. 55, nr 2

285--290

EN

Purpose: The most popular method of aluminium refining is blowing of refining gas through the liquid metal. The way the refining gas is introduced to the liquid metal significantly influences the time and course of degassing process. Rotary impellers seem to be the best solution, especially taking into account reaching good level of gas dispersion in the liquid aluminium. However, the construction of impellers also influences the obtained gas dispersion in liquid metal, especially considering the processing parameters such as flow rate of refining gas and rotary impeller speed. Design/methodology/approach: To observe the phenomena occurring during the aluminium refining process physical modelling was applied. Test stand for such modelling was built at 1:1 scale with the transparent tank to observe the level of gas dispersion in the liquid. The built model has to fulfill the rules coming from the theory of similarity. Findings: The choice of optimal parameters is very important to the particular type of impeller. As a result of research the processing parameters were chosen to the appropriate type of gas dispersion. The most desirable type of dispersion is an uniform dispersion. According to the research the best impeller seems to be impeller No 1. Research limitations/implications: There are differences between results coming from modelling research and industrial test. So, the further research should be conducted with a chosen impeller in industrial conditions. Practical implications: From industrial point of view it is important to test the impeller construction and their geometry in laboratory before industrial test. It gives some ideas how the particular impeller will behave in industry. To control the process of aluminium refining and conducting it optimally it is really important to know its mechanism better. Originality/value: This paper presents original modelling research of aluminium refining process conducted in URO-200 reactor.

7

Modelling steel’s homogenization during argon purging

100%

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

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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tom 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.

8

Zastosowanie modelowania fizycznego w pomiarach przemieszczeń względnych

100%

Kocańda A. , Świłło S.

Przegląd Mechaniczny

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2001

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tom nr 4

16-19

PL

Przedstawiono zastosowanie modelowania fizycznego do analizy procesów obróbki plastycznej, na przykładzie procesu kucia zaproponowano metodę wyznaczania przemieszczeń względnych na powierzchni kontaktu matrycy z odkztałcanym materiałem, wielkość ta obok nacisków jeddnostkowych jest podstawowym czynnikiem decydującym o zużyciu ściernym matryc.

EN

Application of physical modelling for analysing processes of plastic working. Basing on a forging process a method was proposed for determining relative displacements on the surface of the contact between the die and the material being formed. This quantity apart from the unit pressures is a basic factor responsible for abrasive wear of the dies. This example shows new possibilities in the field of using the technique of physical modelling that assisted by an image recording system has become a precious tool in solving problems of plastic forming.

9

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

100%

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

Archives of Metallurgy and Materials

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2016

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tom 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.

10

Wpływ warunku podobieństwa w zakresie plastycznym na modelowanie fizyczne osiowosymetrycznego wyciskania przeciwbieżnego

100%

Gronostajski Z. , Hawryluk M.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2003

|

tom z. 201

25--30

PL

W pracy przedstawiono zagadnienia związane z modelowaniem fizycznym procesu osiowosymetrycznego wyciskania przeciwbieżnego ołowiu. Porównano wyniki uzyskane z modelowania fizycznego z wynikami otrzymanymi z eksperymentu rzeczywistego. Ponadto omówiono wpływ dokładności dopasowania krzywej naprężenie uplastyczniające-odkształcenie materiału modelowego do materiału rzeczywistego na wyniki uzyskane z modelowania fizycznego.

11

Modelowanie fizyczne jako metoda weryfikacji obliczeń numerycznych

100%

Presz W. , Wanheim T.

Prace Naukowe Politechniki Warszawskiej. Mechanika

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2003

|

tom z. 201

19--24

PL

Przeprowadzono próby wyciskania współbieżnego w płaskim stanie odkształcenia dla różnych kątów matrycy, dwóch warunków tarcia i dwóch materiałów modelowych na bazie wosku. W ściankach matrycy umieszczono czujniki rejestrujące naciski w trakcie procesów. Wyniki porównano z obliczeniami numerycznymi w celu ich weryfikacji. Naciski uzyskane z eksperymentu były zgodne z obliczeniami tylko dla niskiego czynnika tarcia. W przypadku skrajnym niezgodność sięgała nawet 70%.

EN

The test stand based on physical modeling technique has been comleted to validate results of FEM simulations mainly in the aspect of friction model. Plane strain forward extrusionswith different angles, different materials and different friction conditions have been carried outwith strain gagues membrane pressure sensors positioned on a side and top of die. Recorded pressure distribution on tool surface during deformation process has been used for evaluation of Commercial FEM package.

12

A Physical Model of the Nonlinear Sitar String

100%

Siddiq S.

Archives of Acoustics

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2012

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tom Vol. 37, No. 1

73-79

EN

The acoustic properties of the sitar string are studied with the aid of a physical model. The nonlinearity of the string movement caused by the bridge acting as an obstacle to the vibrating string is of special interest. Comparison of the model’s audio output to recordings of the instrument shows interesting similarities. The effects dispersion and bridge have on the sound of the instrument are demonstrated in the model.

13

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

100%

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

Archives of Metallurgy and Materials

|

2019

|

tom 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.

14

Model naprężeń i zmian kształtu wyrobów długich podczas kontrolowanego chłodzenia po przeróbce plastycznej na gorąco

100%

Dudek K. , Pietrzyk M.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2003

|

tom z. 201

115--120

PL

W artykule przedstawiono wyniki prac dotyczących modelowania naprężeń i zmian kształtu wyrobów długich podczas chłodzenia po przeróbce plastycznej na gorąco. W proponowanym modelu termomechanicznym dla ciała sprężysto-plastycznego uwzględniono efekt przemian fazowych. Obliczenia przeprowadzono dla pełnego modelu 3D oraz przedstawiono propozycje rozwiązania opartego o model 2D.

EN

The paper presents model of stress and changes of shape of sections during controlled cooling after hot rolling. Proposed thermo-mechanical model for elasto-plastic material accounts for the phase change effect. The calculations for the full 3D model, as well as the proposition of the solution based on the 2D approach, are presented in the paper.

15

Optymalizacja planu gniotów w celu uzyskania zadanej wielkości ziarna austenitu w stali 304L

100%

Svietlichnyj D.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2003

|

tom z. 201

79--84

PL

W pracy przedstawiono nową metodę projektowania planu gniotów opartą o teorię sterowania optymalnego. Zastosowanie metod teorii sterowania do projektowania technologii procesów plastycznej przeróbki metali pozwala zmniejszyć koszty związane z projektowaniem, wyznaczeniem optymalnego planu procesu walcowania wkilku przepustach, zabezpieczeniem wymaganej jakości wyrobów i osiągnięciem powtarzalności wyników. Optymalne parametry procesu walcowania wyznaczono wychodząc z zadanej wielkości ziarna austenitu, po ostatnim przepuście. Badania przeprowadzono dla stali austenitycznej 304L. Zastosowany model do optymalizacji planu gniotów zawiera modele związane zarówno z procesem walcowania, jak i z procesami rozwoju mikrostruktury. Dla walcowni nawrotnych podstawowymi parametrami, za pomocą których można sterować rozwojem mikrostruktury i odpowiednio końcową wielkością ziarna austenitu, są początkowa temperatura, gnioty oraz czasy przerw między przepustami. W modelu zastosowano również ogranicznia ze względu na temperaturę, parametry energetyczno-siłowe oraz czasy przerw.

EN

The paper presents new method of rolling schedule design, which is based on optimal control theory. Application of the methods of control theory to technology design allows whittling down expenses in design and optimization of rolling schedule as well as they are helpful in the ensuring of product liability. Optimal parameters are dependant on final grain size of austenite. Studies were done for austenitic steel 304L. Model, which was used to optimization multi-pass flat rolling process, consists of two parts: rolling process part and microstructure development part. There are two vector parameters, which control microstructure development and eventually final grain size. They are reductions in every pass and pauses between passes. There are several constrains taken into account in the model: temperature, rolling force and torque, reductions and pauses. The paper deals with examples of pass schedule design calculated design calculated according to the model.

16

Analiza procesu asymetrycznego walcowania blachy bimetalowej Al-Cu

100%

Rydz D. , Skoblik R.

Prace Naukowe Politechniki Warszawskiej. Mechanika

|

2003

|

tom z. 201

73--77

PL

W pracy podkreślono wpływ asymetrii predkości obwodowej walców na wygięcie blachy bimetalowej Al-Cu. Wprowadzenie asymetrycznego procesu walcowania do wytwarzania blach bimetalowych ma na celu zwiększenie predkości płynięcia warstwy o większym oporze odkształcenia oraz zwiększenie równomierności rozkładu odkształcenia całkowitego na warstwy pasma. Ponadto w pracy określono optymalne wartości współczynnika asymetrii "av", dla których uzyskano proste pasmo bimetalowe. Badania numeryczne przeprowadzono w programie komputerowym FORGE2D.

EN

In this work the influence of peripheral speedasymmetry of rolls on bending of Al-Cu bimetallic plate was assessed. Application of asymmetrical rolling for bimetallic plates formation is aimed to increase of flow velocity of a layer of greater determination resistance and to increase of uniformity of total determination disintegration into band layers. Optimal values of asymmetry coefficient "av" was assessed, for which a straight bimetallic bend was obtained. Numerical examinations were carried out by means of FORGE2D computer program.

17

100%

Kasprzak W. A.

Journal of Theoretical and Applied Mechanics

|

2003

|

tom Vol. 41 nr 2

383-394

EN

The problem of similarity and designing of a physical model of an examined process is considered on the basis of generalizations of Theorem ... . It is shown that in cases of nonscalar description the similar model of a process could be designed on the basis a special version of Theorem ... . Similarity scales can be obtained only for the vector modulus, or for the components of vectors and tensors when special experimental condotions (described in this paper) are fulfilled.

PL

Znana z literatury teoria podobieństwa modelowego i algorytmy projektowania modeli opracowano przy założeniu, że proces zależy od zmiennych, które są skalarami. W pracy podaje się rozwiązanie tych problemów dla nieskalarnych zmiennych, od których zależy przebieg procesu. Podaje się odpowiednią wersję twirdzenia ... dla funkcji wymiarowych zależnych od zmiennych, które mogą być tensorami i sposób wyznaczania skal. Pokazuje się, że otrzymuje się takie same rezultaty, jak dla modeli skalarnych, ale otrzymuje się pełną informację o składowych tensora opisującego badany proces, a więc pełne informacje pozwalające na opracowanie projektu badań empirycznych (nie otrzymywano ich w tradycyjnym modelu).

18

Comparison analysis of cockroft – latham criterion values of commercial plasticine and C45 steel

100%

Wójcik Ł. , Pater Z.

Acta Mechanica et Automatica

|

2018

|

tom Vol. 12, no. 4

286--293

EN

The paper presents and compares the results of theoretical and experimental research in the field of cracking of model material (commercial plasticine) and C45 steel in hot forming conditions. The aim of the research was to determine the limit values of the CockroftLatham integral for both materials. The presented research methodology includes experimental tests (tensile tests) and numerical simulations carried out in the DEFORM-3D program. For laboratory tests, axially symmetric samples made of C45 steel and model material were used. On the basis of the obtained experimental and numerical results, a comparative analysis of both materials was carried out.

19

Numerical and Experimental Modeling of Plastic Deformation the Multi-Layer Ti/Al/Mg Materials

100%

Mróz S. , Stefanik A. , Szota P. , Kwapisz M. , Wachowski M. , Śnieżek L. , Gałka A. , Szulc Z.

Archives of Metallurgy and Materials

|

2019

|

tom Vol. 64, iss. 4

1361--1368

EN

The paper has presented the results of theoretical studies and experimental tests of the plastic deformation of multi-layered Ti/Al/Mg specimens. Theoretical studies were carried out using the Forge2011® computer program. Physical modeling, on the other hand, was performed using the Gleeble3800 simulator. Cuboidal specimens were cut off from the plates obtained in the explosive welding method. Based on the obtained investigation results it has been found non uniform deformation of the particular layer as a result their different value of flow stress.

20

Physical Modelling of Degassing Process by Blowing of Inert Gas

88%

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

Archives of Metallurgy and Materials

|

2018

|

tom 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.