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Tytuł:
Evaluation of the activity of irradiated graphite in the Ignalina Nuclear Power Plant RBMK-1500 reactor
Autorzy:
Ancius, D.
Ridikas, D.
Remeikis, V.
Plukis, A.
Plukiene, R.
Cometto, M.
Powiązania:
https://bibliotekanauki.pl/articles/148874.pdf
Data publikacji:
2005
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
modeling
activation analysis
radioactive waste
graphite
Opis:
Ignalina NPP Unit 1 with the RBMK-1500 type reactor enters the preparatory stage for its decommissioning. A big volume of graphite has to be dismantled and managed. This paper evaluates the composition of radionuclides in irradiated graphite on the basis of the calculation scheme with computer codes MCNPX and CINDER'90. Full scale calculations take into account the whole energy spectrum of neutrons, the spatial neutron flux in different reactor structures and the impurities of RBMK-1500 graphite measured by two independent methods. Principal contributors to the total activity as well as other radionuclides important from the radiological point of view are identified. The uncertainties of such calculations are discussed.
Źródło:
Nukleonika; 2005, 50, 3; 113-120
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear Mechanism of Spheroidal Cast Iron Piston Ring-Aluminum Matrix Composite Cylinder Liner Contact
Autorzy:
Bąkowski, H.
Powiązania:
https://bibliotekanauki.pl/articles/352888.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast iron
spheroidal graphite
wear mechanism
stereological parameters
Opis:
The paper presents the results of research on the impact of stereological characteristics of microstructure of graphite in nodular GJS-400 cast iron and Al2 O3 fibers in the composite AC-47000 + 10% Al2 O3 F on the mechanism of wear in a cast iron piston ring – composite cylinder liner contact in a combustion engine. To elucidate the mechanisms of wear in the tested contact was used Finite Element Method (FEM). On the basis of quantitative metallographic examination of test materials were determined stereological parameters of their structures. It was necessary for the implementation of the 3D model that reflects the actual structure with particular focus on the different phases in order to determine the distribution of stresses and strains. The determination Strains of the local stresses value of allowed the prediction of wear initiating places. Formation of stereological parameters of cast iron in the technological process allows a prediction of values and distributions of the stresses/strains and thus reduce wear and extend durability of the analyzed contact.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 1; 481-490
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prediction of Chunky Graphite in Nodular Cast Iron on the Base of Numerical Simulation and Experimental Data
Autorzy:
Bauer, B.
Mihalic Pokopec, I.
Petrič, M.
Mrvar, P.
Powiązania:
https://bibliotekanauki.pl/articles/352270.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
chunky graphite
nodular cast iron
numerical simulation
cooling curve
microstructure
Opis:
Chunky graphite has been recognized for a long time as one of the major problems in production of heavy section nodular cast iron. A great number of studies have been conducted to describe the chunky graphite formation, but a clear understanding of its appearance and a safe mastering of the melt preparation to avoid chunky graphite are not yet available. In the present work the cooling curves were recorded in large cone blocks and standard TA cup. According to measured data from the cone block, melt characteristics and heat transfer coefficient between casting and mould were adjusted in the ProCAST® simulation software. For a near-eutectic nodular cast iron test melt with 0.7 wt.% Ni, relationship between the area of the cone block affected by chunky graphite and simulation software results has been observed, i.e., thermal modulus and time to solidus.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 1; 343-347
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Structural Parameters - the Shape of Graphite and Matrix on Change of Ultrasonic Wave Propagation Rate and Value of Attenuation in Graphitic Cast Irons
Autorzy:
Belan, Juraj
Tillová, Eva
Uhríčik, Milan
Pastierovičová, Lucia
Powiązania:
https://bibliotekanauki.pl/articles/26081550.pdf
Data publikacji:
2023
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
badanie ultradźwiękowe
zapewnienie jakości żeliwa
grafitowy kształt
współczynnik perlitu i ferrytu
ultrasonic investigation
quality assurance of cast iron
graphite shape
pearlite and ferrite ratio
quantitative evaluation of graphite and matrix
Opis:
Despite the tendency of the current industry, especially the automotive industry, it is to use modern, light and super-strong materials based on Al or HSLA steels, the application of classic materials such as cast iron still makes sense, especially concerning price and excellent castability. The article presents one of the possible ways of using the ultrasonic non-destructive method in quality control and simpli-fication of the identification of the type of cast iron concerning the change of parameters of ultrasound propagation in materials. The main criteria for assessing the quality and determining the type of graphite cast iron were considered to be the rate of propagation of ultrasound - cL and the value of attenuation , which vary depending on the shape of the graphite and matrix. Graphitic cast irons with different graphite shapes (lamellar, vermicular, and globular shapes) and a matrix with different ferrite/perlite ratios were used as experimental material. Along with the ultrasonic tests, a metallographic analysis was also performed to quantify the microstructure of cast irons.
Źródło:
Production Engineering Archives; 2023, 29, 1; 23--27
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlations between Structures of Expanded Graphite - Polymer Composites and Acoustic Emission Phenomena
Korelacje pomiędzy strukturą kompozytów grafit ekspandowany-polimer a zjawiskami emisji akustycznej
Autorzy:
Berdowska, A.
Berdowski, J.
Aubry, F.
Powiązania:
https://bibliotekanauki.pl/articles/355731.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressed expanded graphite
polymer
composite
acoustic emission parameters
grafit ekspandowany
polimer
kompozyty
parametry emisji akustycznej
Opis:
Compressed expanded graphite was applied as a base matrix to the preparation of microporous composites as products of impregnation, polymerization and carbonization of poly-furfuryl alcohol. During carbonization, the original polymeric structure is transformed into an amorphous turbostratic carbon structure with ultramicropores. The structure, porosity and many chemical and physical properties change after each stage of their technological treatment. The acoustic emission method was used for accurate determination of these changes. It is possible to determine a large number of acoustic emission parameters and therefore to increase the amount of information provided by the studied materials. Acoustic emission pulses, counts rate, events rate, signal peak value and their sums were measured. Also frequency spectrum was received as a result of acoustic emission signal analysis with use of Fourier transformation procedure. The conclusions resulting from the Fourier analysis of the registered spectrum are very interesting and provide information about composite structures as well as bonds between the graphite matrix and the polymer that fills it. Analysis of acoustic emission parameters provides data on physical and chemical processes that would be very difficult to study by means of other techniques. Wide applications of these porous composites make them very interesting subject of the study.
Sprasowany grafit ekspandowany użyto jako bazową matrycę do wytworzenia mikroporowatych kompozytów będących produktami impregnacji, polimeryzacji i karbonizacji alkoholu polifurfurylowego. Podczas procesu karbonizacji oryginalna struktura polimerowa jest przekształcana w strukturę turbostratyczną węgla amorficznego z ultramikroporami. Struktura, porowatość oraz wiele chemicznych i fizycznych własności ulega zmianie na poszczególnych etapach technologicznego procesu. Metodę emisji akustycznej użyto w celu dokładnego przebadania tych zmian. Możliwym jest wyznaczenie w eksperymentach dużej liczby parametrów emisji akustycznej co pozwala uzyskać dużą ilość informacji o badanych materiałach. Zmierzono następujące parametry emisji akustycznej: szybkość zliczeń, szybkość zdarzeń, amplituda impulsu, średnia wartość skuteczna sygnałów oraz sumy tych parametrów. Także analizowano widmo częstotliwościowe sygnałów przy pomocy transformaty Fouriera. Wnioski wynikające z analizy fourierowskiej widm są niezwykle interesujące i dostarczają informacje o strukturze kompozytów oraz o wiązaniach między grafitową matrycą a polimerem wypełniającym ją. Analiza parametrów emisji akustycznej dostarcza wielu danych o fizycznych i chemicznych własnościach, które byłyby bardzo trudne do zbadania przy użyciu innych metod. Szerokie zastosowania omawianej grupy porowatych kompozytów czyni je bardzo interesującym przedmiotem badań.
Źródło:
Archives of Metallurgy and Materials; 2015, 60, 4; 2479-2484
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of Graphite - Polymer - Turbostratic Carbon Composites by Acoustic Emission Method at Perpendicular Geometry
Autorzy:
Berdowska, A.
Berdowski, J.
Aubry, F.
Powiązania:
https://bibliotekanauki.pl/articles/356589.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressed expanded graphite
polyfurfuryl alcohol
turbostratic carbon
acoustic emission
composite membrane
Opis:
The purpose of this paper was to search the relations between the structure of the compressed expanded graphite–polymer–turbostratic carbon composites on successive stages of technological treatment and parameters describing the acoustic emission phenomena in these materials. The acoustic emission method can be used for measurements of changes in the structure and many different properties of materials. These investigations are a continuation of our earlier studies concerning physical, mechanical and chemical properties of porous composites created on the basis of a compressed expanded graphite matrix, obtained after successive technological procedures of impregnation, polymerization and carbonization of polyfurfuryl alcohol. The aim of this work was to investigate materials obtained at different levels of technological processing, thus with different densities, porosity, physical and chemical properties, by using the acoustic emission method. In compressed expanded graphite composites structures one can differentiate two basic directions: perpendicular to the bedding plane of graphite flakes and parallel to this one. The all presented results were obtained for the uniaxial strain applied in the direction perpendicular to the bedding plane of the composite structure. Analysis of acoustic emission parameters provides information on physical and chemical processes in these materials.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1287-1293
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The relationship between the structural anisotropy of the PFA polymer/compressed expanded graphite-matrix composites and acoustic emission characteristics
Autorzy:
Berdowska, Sylwia
Berdowski, Janusz
Aubry, Frederic
Powiązania:
https://bibliotekanauki.pl/articles/2086891.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
acoustic emission
spectrum distribution
anisotropic structures
polyfurfuryl alcohol
compressed expanded graphite
composite membrane
emisja akustyczna
rozkład widma
struktura anizotropowa
alkohol polifurfurylowy
grafit ekspandowany prasowany
membrana kompozytowa
Opis:
The main aim of the study was to search for the relationship between the anisotropy of the structure of polyfurfuryl alcohol (PFA) – polymer/compressed expanded graphite (CEG)-matrix composites at subsequent stages of the technological process and characteristics of the acoustic emission (AE) descriptors. These composites, obtained after successive technological procedures of impregnation, polymerization, and carbonization, possess different structure, densities, porosity, and other physicochemical properties. In the structures of composites prepared on the basis of CEG, two basic directions can be distinguished: parallel to the bedding plane of graphite sheets and perpendicular to it. The measurements were carried out for the stress acting in these two main directions. The investigation has shown that the AE method enables the detection of anisotropy in the structure of materials. The results of the research show that all four of the acoustic emission descriptors studied in this work are sensitive to the technological stages of these materials on the one hand and their structure anisotropy on the other. Fourier analysis of the recorded spectra provides interesting conclusions about the structural properties of composites as well as a lot of information about the bonding forces between the carbon atoms of which the CEG matrix is composed and the PFA polymer or turbostratic carbon.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2021, 69, 5; e138235, 1--8
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Study of properties of expanded graphite - polymer porous composite by acoustic emission method
Badanie właściwości porowatych kompozytów grafit ekspandowany - polimer metodą emisji akustycznej
Autorzy:
Berdowski, J.
Berdowska, S.
Aubry, F.
Powiązania:
https://bibliotekanauki.pl/articles/351501.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compressed expanded graphite
polymerization
carbonization
composite membrane
acoustic emission
sprasowany grafit ekspandowany
polimeryzacja
zwęglanie
membrana kompozytowa
emisja akustyczna
Opis:
The purpose of this paper was to investigate the physical and mechanical properties of compressed expanded graphite (CEG) and their porous derivatives after impregnation, polymerization; and carbonization by the use of acoustic emission method (AE). The mechanical and structural characteristics of compressed expanded graphite and their three groups of porous composites after each technological process are presented and discussed. The measurements of acoustic emission parameters in these materials were carried out at wide range of frequency of the waves (0.1÷2.5 MHz). The changes of two of parameters: - AE pulses counts rate and spectrum distribution of AE waves - are presented in this paper. The analysis of the respective parameters AE also gives possibility to determine the micro- and macro structural changes of materials at different levels of technological processes. Applications of these materials as catalysts with high specific surface make them very interesting subject of study. Also compressed expanded graphite composite membranes prepared from furfuryl alcohol polymers are promising for gas separation.
Cel pracy stanowiło zbadanie przy użyciu metody emisji akustycznej (EA) fizycznych i mechanicznych właściwości sprasowanego grafitu ekspandowanego (SGE) i jego porowatych pochodnych kompozytowych, otrzymanych po procesach impregnacji, polimeryzacji i karbonizacji. Przedstawiono i przedyskutowano mechaniczne i strukturalne charakterystyki sprasowanego grafitu ekspandowanego i trzech porowatych kompozytów otrzymanych na jego bazie, po kolejnych procesach technologicznych. Pomiary parametrów zarejestrowanych sygnałów EA w tych materiałach wykonano w szerokim przedziale częstotliwości emitowanych w materiale fal (0,1-2,5 MHz). W pracy przedstawiono zmiany dwu z tych parametrów: szybkości zliczeń impulsów i rozkładu widmowego emitowanych fal. Analiza poszczególnych parametrów emisji akustycznej stwarza możliwości określenia mikro- i makrostrukturalnych zmian w materiałach, wytworzonych na różnych etapach procesu technologicznego. Przewidywane szerokie zastosowanie tych materiałów jako katalizatorów, posiadających bardzo duże powierzchnie właściwe, czyni je niezwykle interesującym przedmiotem badań. Również bardzo perspektywiczne jest wykorzystanie kompozytowych membran z matrycą ze sprasowanego grafitu ekspandowanego, wypełnionego polimerem alkoholu furfurylowego. do separacji gazów.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 4; 1331-1336
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Segregation of Admixing Elements in the Boundary Layer of the Main Inlet of a Ductile Iron Casting
Autorzy:
Borowiecki, B.
Mak, S.
Powiązania:
https://bibliotekanauki.pl/articles/382659.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ductile iron
nodular graphite
boundary layer
żeliwo sferoidalne
grafit sferoidalny
warstwa przyścienna
Opis:
The object of the present paper is to determine the distribution of admixing elements, such as magnesium, manganese, silicon and sulfur, in the boundary layer of the main inlet of a ductile iron casting. The authors also intend to demonstrate the influence of elements diffusing from the casting mold, such as oxygen and silica, on the chemical composition of the boundary layer of the casting.
Źródło:
Archives of Foundry Engineering; 2013, 13, 2 spec.; 10-17
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of a manufacturing technology of compacted graphite iron castings from a cupola furnace
Autorzy:
Bouska, O.
Heunisch, J.
Zadera, A.
Nedelova, K.
Kobersky, F.
Powiązania:
https://bibliotekanauki.pl/articles/382494.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
grafit zagęszczony
żeliwo sferoidalne
żeliwiak
modyfikacja
compacted graphite iron
cupola furnace
modification
Opis:
Compacted graphite iron, also known as vermicular cast iron or semiductile cast iron is a modern material, the production of which is increasing globaly. Recently this material has been very often used in automotive industry. This paper reviews some findigs gained during the development of the manufacturing technology of compacted graphite iron under the conditions in Slévárna Heunisch Brno, Ltd. The new technology assumes usage of cupola furnace for melting and is beeing developed for production of castings weighing up to 300 kilograms poured into bentonite sand moulds.
Źródło:
Archives of Foundry Engineering; 2012, 12, 1; 125-129
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artificial Intelligence Approaches to Determine Graphite Nodularity in Ductile Iron
Autorzy:
Brait, Maximilian
Koppensteiner, Eduard
Schindelbacher, Gerhard
Li, Jiehua
Schumacher, Peter
Powiązania:
https://bibliotekanauki.pl/articles/2056034.pdf
Data publikacji:
2021
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
ductile iron
graphite nodularity
graphite morphology
artificial intelligence
machine learning
żeliwo sferoidalne
guzkowatość grafitu
morfologia grafitu
sztuczna inteligencja
uczenie maszynowe
Opis:
The complex metallurgical interrelationships in the production of ductile cast iron can lead to enormous differences in graphite formation and local microstructure by small variations during production. Artificial intelligence algorithms were used to describe graphite formation, which is influenced by a variety of metallurgical parameters. Moreover, complex physical relationships in the formation of graphite morphology are also controlled by boundary conditions of processing, the effect of which can hardly be assessed in everyday foundry operations. The influence of relevant input parameters can be predetermined using artificial intelligence based on conditions and patterns that occur simultaneously. By predicting the local graphite formation, measures to stabilise production were defined and thereby the accuracy of structure simulations improved. In course of this work, the most important dominating variables, from initial charging to final casting, were compiled and analysed with the help of statistical regression methods to predict the nodularity of graphite spheres. We compared the accuracy of the prediction by using Linear Regression, Gaussian Process Regression, Regression Trees, Boosted Trees, Support Vector Machines, Shallow Neural Networks and Deep Neural Networks. As input parameters we used 45 characteristics of the production process consisting of the basic information including the composition of the charge, the overheating time, the type of melting vessel, the type of the inoculant, the fading, and the solidification time. Additionally, the data of several thermal analysis, oxygen activity measurements and the final chemical analysis were included. Initial programme designs using machine learning algorithms based on neural networks achieved encouraging results. To improve the degree of accuracy, this algorithm was subsequently adapted and refined for the nodularity of graphite.
Źródło:
Journal of Casting & Materials Engineering; 2021, 5, 4; 94--102
2543-9901
Pojawia się w:
Journal of Casting & Materials Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of Wear Mechanisms of Graphites Used for Crystallisers for Continuous Casting
Autorzy:
Brudny, Anna
Kulasa, Joanna
Juszczyk, Barbara
Myalski, Jerzy
Roskosz, Stanisław
Wycisk, R.
Kwaśniewski, Paweł
Strzępek, Paweł
Poręba, Marek
Powiązania:
https://bibliotekanauki.pl/articles/2203941.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
innovative foundry technologies
innovative foundry materials
wear resistance
graphite
crystallizers
tribology
innowacyjne technologie odlewnicze
innowacyjne materiały odlewnicze
odporność na zużycie
grafit
krystalizatory
tribologia
Opis:
This paper presents the results of research concerning the evaluation of tribological properties of graphite materials used, among others, for crystallisers for continuous casting of non-ferrous metals and their alloys. Graphite materials differing not only in their physical properties but also in the technology of their production were selected from a wide range of commercially available products. Wear resistance investigations of the tested graphite materials were carried out on a pin-on-disc tribometer under technically dry friction conditions on a sliding distance of 1000 m. A constant load but variable speed was used in the tests. The mean value of the coefficient of friction and the wear of the material were determined based on the tribological tests carried out. It was observed that as the speed increases, the average value of the coefficient of friction decreases, while the wear increases. A microstructural analysis of the wear track showed that the friction mechanism depends mainly on the graphite formation technology, which is related to the microstructure of the tested materials, and to a lesser extent to their physical and mechanical properties. Varying the speed values made it possible to trace changes in the wear mechanism, on the basis of which it is possible to predict the durability and reliability of graphite crystalliser operation.
Źródło:
Archives of Foundry Engineering; 2022, 22, 4; 109--115
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparison of mechanical flotation cell and cyclonic microbubble flotation column in terms of separation performance for fine graphite
Autorzy:
Bu, X.
Zhang, T.
Chen, Y.
Peng, Y.
Xie, G.
Wu, E.
Powiązania:
https://bibliotekanauki.pl/articles/110791.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
mechanical flotation
column flotation
Fuerstenau upgrading curve
graphite
Opis:
Comparison of flotation performance between the flotation column and mechanical flotation was carried out to promote the grade and economic value of the graphite ore (15.40% ash content). The ash content of the concentrate of the mechanical flotation was 10.77% at the yield of 79.34%. In contrast, the yield of the concentrate of the column flotation was increased to 88.93% with 10.55% ash content. Comparative study of the Fuerstenau upgrading curves indicated that the column flotation was more efficient for cleaning the graphite ore in the presence of the centrifugal force field, nanobubbles (generated by hydrodynamic cavitation), and the thicker froth layer in comparison with the mechanical flotation.
Źródło:
Physicochemical Problems of Mineral Processing; 2018, 54, 3; 732-740
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of averaged Voronoi polyhedron in the modelling of crystallisation of eutectic nodular graphite cast iron
Autorzy:
Burbelko, A. A.
Początek, J.
Królikowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/381559.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
cast iron
nodular graphite
modelling
averaged Voronoi polyhedron
żeliwo
grafit kulkowy
modelowanie
wielościan Voronoia
Opis:
The study presents a mathematical model of the crystallisation of nodular graphite cast iron. The proposed model is based on micro- and macromodels, in which heat flow is analysed at the macro level, while micro level is used for modelling of the diffusion of elements. The use of elementary diffusion field in the shape of an averaged Voronoi polyhedron [AVP] was proposed. To determine the geometry of the averaged Voronoi polyhedron, Kolmogorov statistical theory of crystallisation was applied. The principles of a differential mathematical formulation of this problem were discussed. Application of AVP geometry allows taking into account the reduced volume fraction of the peripheral areas of equiaxial grains by random contacts between adjacent grains. As a result of the simulation, the cooling curves were plotted, and the movement of "graphite-austenite" and "austenite-liquid” phase boundaries was examined. Data on the microsegregation of carbon in the cross-section of an austenite layer in eutectic grains were obtained. Calculations were performed for different particle densities and different wall thicknesses. The calculation results were compared with experimental data.
Źródło:
Archives of Foundry Engineering; 2013, 13, 1; 134-140
1897-3310
2299-2944
Pojawia się w:
Archives of Foundry Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wear resistance of graphitized steels
Odporność grafityzowanej stali na zużycie ścierne
Autorzy:
Byelikov, S
Volchok, I.
Akimov, I
Powiązania:
https://bibliotekanauki.pl/articles/351033.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
graphitized steel
graphite inclusions
wear resistance
stal grafityzowana
wydzielenia grafitu
zużycie ścierne
Opis:
Heat-treated graphitized steels with different carbon, silicon and copper contents have been the object of study. The influence of the composition on the structure and wear resistance (weight loss of the specimen) of graphitized steels (after hardening and tempering) under the conditions of metal to metal dry sliding friction with the use of Amsler-type friction machines, has been investigated in this work. Research results have shown that the main factors affecting wear resistance of graphitized steels have been not only their metal base hardness, but the quantity, shape and distribution of graphite inclusions uniformity in the structure of such steels as well. A regression dependence of the quantity of specimen’s weight loss on carbon, silicon and copper content has been obtained in the work. The highest wear resistance was pertained by the steel having the following content: 1.60. . . 1.70%C; 2.20. . . 2.30%Si; 0.80. . . 0.90%Cu; 0.60. . . 0.70%Mn; 0.15. . . 0.18%Cr; 0.22. . . 0.25%Al; up to 0.015%S and 0.024%P.
Przedmiotem badań była grafityzowana stal (po obróbce cieplnej) o zróżnicowanej zawartości węgla, krzemu oraz miedzi. W pracy przedstawiono wyniki badań wpływu składu chemicznego grafityzowanej stali, po hartowaniu i odpuszczaniu, na jej strukturę i zużycie ścierne (zmniejszenie masy próbki) w warunkach suchego tarcia ”metal-metal” na maszynie typu Amslera. Wyniki badań świadczą o tym, że odporność na zużycie ścierne zależy nie tylko od twardości osnowy metalowej, lecz także od ilości, kształtu i jednorodności wydzieleń grafitu oraz rozkładu przestrzennego wtrąceń w strukturze stali tego typu. Otrzymano zależności regresyjne wartości ubytku masy próbek w funkcji zawartości węgla, krzemu i miedzi. Największą odpornością na zużycie ścierne wyróżniają się stale o następującym składzie chemicznym: 1,60. . .1,70% C, 2,20. . . 2,30% Si, 0,80. . . 0,90% Cu, 0,60. . . 0,70% Mn, 0,15 . .. 0,18% Cr, 0,22. . . 0,25% Al, do 0,015% S i 0,024% P.
Źródło:
Archives of Metallurgy and Materials; 2013, 58, 3; 813-816
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 161

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