Wyniki wyszukiwania - Biblioteka Nauki

1

Sensitivity of Crystallization Process with Respect to Cooling Conditions

100%

Szopa R. , Wojciechowska W.

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2002

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tom z. 75

159-162

EN

In the paper we use the sensitivity analysis method in order to investigate the influence of external cooling conditions on the course of casting solidification. The model of thermal processes proceeding in the domain considered corresponds to the second generation one. As an example we present the sensitivity of transient temperature field in casting volume on the changes of the mould thermal conductivity. In the final part of the paper the example of computations is shown.

2

Nickel in Compacted Graphite Iron

80%

Gumienny G. , Kurowska B. , Szymczak T. , Gawroński J.

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2017

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tom Vol. 62, iss. 2A

657--662

EN

The paper presents results of the research work concerning effects of nickel concentration on the crystallization process, microstructure and selected properties of the compacted graphite iron. Compacted graphite in the cast iron was obtained with use of the Inmold process. The study has comprised the cast iron containing nickel up to concentration providing obtainment of austenitic microstructure of the matrix. The effect of the nickel on temperature of the eutectic crystallization was specified. It has been presented composition of the cast iron matrix in function of nickel concentration in a casting with wall thickness of 3 mm and 24 mm. Moreover, it has been presented conditions defining the possibility of obtaining an austenitic and martensitic compacted graphite iron. Effect of the nickel on hardness of the cast iron was described.

3

Analysis of crystallization process of selected Fe-based bulk metallic glasses

80%

Babilas R. , Nowosielski R. , Pilarczyk W. , Sakiewicz P.

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2012

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tom Vol. 55, nr 2

225--229

EN

Purpose: The paper mainly aims to present the influence of annealing temperature on structural changes and magnetic properties of selected Fe-based bulk metallic glasses with chemical composition of Fe43Co14Ni14B20Si5Nb4 (at.%). Design/methodology/approach: The investigated samples were cast in form of the rods with diameter of 1.5 mm by the pressure die casting method. The structure changes in function of annealing temperature were examined by X-ray diffraction (XRD) and transmission electron microscopy (TEM) methods. The crystallization behaviour of the studied alloy was also examined by differential scanning calorimetry (DSC). Magnetic measurements of annealed samples included the initial magnetic permeability and the magnetic permeability relaxation measurements. Findings: The annealing process at temperature range from 373 to 773 K caused a structural relaxation of tested material, which caused the atomic rearrangements and changes of physical properties in relation to as-cast state. The annealing at higher temperatures (823-923 K) obviously caused a formation of a-Fe and iron borides crystalline phases. The increasing of annealing temperature significantly improved soft magnetic properties of examined alloy by increase the initial magnetic permeability and decrease the magnetic permeability relaxation. Practical implications: The investigation of the crystallization process of Fe-based metallic glasses is important for understanding the mechanisms of forming controlled microstructures of these materials with specific physical properties. Originality/value: A proper understanding of crystallization process of Fe-based bulk metallic glasses is still novel scientific problem.

4

Rejestracja procesów krystalizacji metodą ATND

60%

Ciućka T.

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tom R. 2, nr 44

81--86

PL

W artykule przedstawiono próbę zastosowania jednoczesnej metody Analizy Termiczno-Napięciowo Derywacyjnej do badań metalograficznych stopów metali nieżelaznych. Badania były prowadzone na stopie AK132 i AL99,75 poddanego typowym zabiegom rafinacji i modyfikacji.

EN

The evaluation test of structure properties of the AK132 silumin and AL99,75 have been described in this paper. The characteristics points obtained from the solidification curves and from the electrical curves, as well from their derivatives have been determined on the state of the solidification and crystallization curves using the method simultaneous recording ATND.

5

Zastosowanie metody ATD do kontroli żeliwa wermikularnego

60%

Władysiak R.

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tom R. 2, nr 44

355--364

PL

W pracy przedstawiono wyniki badań procesu krystalizacji metodą ATD żeliwa wermikularnego. Stwierdzono występowanie charakterystycznych różnic między krzywymi ATD żeliwa wyjściowego i wermikularnego oraz istnienie korelacji pomiędzy charakterystycznymi parametrami krzywych ATD a właściwościami Rm, Rp0,2, A5 i HB. Otrzymane wyniki potwierdzają możliwość zastosowania metody ATD do kontroli procesu otrzymywania żeliwa wermikularnego.

EN

The test results of crystallization of cast iron with vermicular graphite, which were made with the thermal-derivative analysis method, have been presented here. The characteristic differences between cast iron before and after the vermicularization have been stated on the derivative curve. It has been proved, that there is a statistic dependence between the characteristic parameters of ATD curves and mechanical properties: Rm, Rp0,2, A5 and HB of this cast iron. The results verify the possibility to use the ATD method to control of production of cast iron with vermicular graphite.

6

The phosphorus interaction on the process forming of primary structure of hypereutectic silumins

51%

Piątkowski J.

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2009

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tom Vol. 9, iss. 3

125-128

EN

In this work the results of investigations concerning the hypereutectic silumins to be used as engine ports have been show. New idea on the interaction mechanism of phosphorus during modification of hypereutectic silumins has been shown. According to this hypothesis the influence of phosphorus is the result of local supercooling caused by evaporation and decompression of phosphorus steam. On the base to propose schematic diagram of the origin of local supercooling as a result of evaporation of phosphorus un microareas with a diversified concentration of silicon of the investigated Al-Si alloys.

7

Wpływ cyrkonu na krystalizację amorficznego stopu Cu60ZrxTi40-x

51%

Zielińska M. , Sieniawski J. , Concustell A. , Surinach S. , Baró M. D.

Inżynieria Materiałowa

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2006

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tom Vol. 27, nr 4

791-794

PL

W pracy omówiono wpływ cyrkonu na proces krystalizacji amorficznego stopu Qi60ZrxTi40-x (x=15, 20, 22, 25, 30). Stopy nagrzewano do temperatury 650 °C z prędkością 20 °C/min i wygrzewano w czasie 1 minuty. Następnie chłodzono je do temperatury pokojowej z prędkością 100 °C/min. Ustalono, że skład fazowy tych stopów po krystalizacji zmienia się i zależy od zawartości tytanu i cyrkonu. W stopie o zawartości Zr-15 % (x=15) występują fazy: heksagonalna Cu51ZrJ4 i te-tragonalna CuT^. Natomiast w pozostałych stopach (x=20,22,25, 30) obecne są tylko fazy o strukturze heksagonalnej Cu51Zr14 oraz Cu2TiZr. Przedstawiono również wyniki pomiarów twardości amorficznego stopu Cu60ZrxTi40-x. Stwierdzono, że amorficzny stop charakteryzuje się dużą twardością. Wprowadzenie dodatku Zr nie wywołuje znaczących zmian jej wartości.

EN

The paper presents the influence of zirconium on the crystallization process of amorphous alloy Gi60ZrxTi40-x (x=15, 20, 22, 25, 30) at the temperature up to 650 °C. Amorphous alloys were heated up to 650 °C at the rate of 20 °C/min, kept 1 minute at this temperature and next cooled down to the room temperature at the rate of 100 °C/min. It was established that the phase composition of amorphous alloys after the crystallization process depends on the titanium and zirconium content For alloy with Zr=15 % the final developed microstructure consists of hexagonal Cu51Zr14 and tetragonal CuTi2 while for other compositions the hexagonal Cu51Zr14 and hexagonal CU2TiZr has been observed. The article presents also the results of mechanical properties of amorphous alloy Cu60ZrxTi40-x, obtained by hardness measurements. It was found that amorphous alloy characterises a large hardness however the addition of Zr has not shown significant differences in its value.

8

Influence of Type and Shape of the Chill on Solidification Process of Steel Casting

51%

Jaromin M. , Dojka R. , Jezierski J. R. , Dojka M.

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tom iss. 1

35--40

EN

The article is a case study of the steel milling ring casting of about 6 tonnes net weight. The casting has been cast in the steel foundry the authors have been cooperating with. The aim was to analyse the influence of the shape of the chills and the material which was used to make them on the casting crystallization process. To optimally design the chills the set of the computer simulation has been carried out with 3 chills’ shape versions and 3 material’s versions and the results have been compared with the technology being in use (no chills). The proposed chills were of different thermal conductivity from low to high. Their shapes were obviously dependant on the adjacent casting surface geometry but were the result of the attempt to optimise their effect with the minimum weight, too. The chills working efficiency was analysed jointly with the previously designed top feeders system. The following parameters have been chosen to compare their effectiveness and the crystallization process: time to complete solidification and so-called fed volume describing the casting feeding efficiency. The computer simulations have been carried out with use of MagmaSoft v. 5.2 software. Finally, the optimisation has led to 15% better steel yield thanks to 60% top feeders weight reduction and 40% shorter solidification time. The steel ring cast with use of such technology fulfil all quality criteria.

9

SiMo Ductile Iron Crystallization Process

51%

Stawarz M.

Archives of Foundry Engineering

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2017

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tom Vol. 17, iss. 1

147--152

EN

The article presents crystallization process of silicon molybdenum ductile cast iron (SiMo). The alloy with 5% silicon content and with variable amounts of Mo in a range of 0-1% was chosen for the research. The carbon content in the analysed alloys did not exceed 3,1%. The studies of crystallization process were based on thermal – derivative analysis (TDA). Chemical composition of all examined samples was analysed with the use of LECO spectrometer. Additionally, the carbon and the sulphur content was determined basing on carbon and sulphur LECO analyser. For metallographic examination the scanning electron microscopy (SEM) with EDS analyser was used. Disclosed phases have been also tested with the use of X-ray diffraction. The results allowed the description of crystallization processes of silicon molybdenum ductile cast iron using thermal – derivative analysis (TDA). Conducted studies did not allow for the clear identification of all complex phases containing molybdenum, occurring at the grain boundaries. Therefore, the further stages of the research could include the use of a transmission electron microscope to specify the description of complex compounds present in the alloy.

10

The Effect of Heat Removal from the Casting Mould on the Crystallization High Silicon Cast Iron

51%

Stawarz M. , Gromczyk M. , Szajnar J.

Archives of Foundry Engineering

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2015

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tom Vol. 15, iss. 2 spec.

83--86

EN

Silicon cast iron with high chemical resistance, which is the biggest advantage of this material, did not have any competition for a long time. It was popular on the market of metal materials because of its low price. However, the production of this material requires special attention and precautions, which is a barrier for foundry. The article presents the results of research of high silicon cast iron crystallization based on thermal derivative analysis (which has identified characteristic temperatures of the investigated alloy crystallization process basis on the part of Fe–Si phase diagram and process analysis using calculations made in Thermo–Calc software) and metallographic analysis of the structure.

11

Crystallization of AlSi17Cu5Mg Alloy after Time-thermal Treatment

51%

Piątkowski J. , Kamiński P.

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tom Vol. 15, iss. 1

83--86

EN

In the dissertation it has been shown, that so called “time-thermal treatment” (TTT) of the alloy in liquid state as overheating the metal with around 250°C above Tliq. and detailing it in temperature for 30 to 40 minutes has the influence on changing the crystallization parameters (Tliq., TEmin., TEmax., TE(Me), TSol.). It was ascertained, that overheating the AlSi17Cu5Mg alloy substantially above Tliq. results with microcrystalline structure. Evenly distributed in the eutectic warp primeval silicon crystals and supersaturated with alloying additives of base content (Cu, Mg, Fe) of α(Al) solution, ensures not only increase durability in ambient temperature, but also at elevated temperature (250°C), what due to it’s use in car industry is an advantage.

12

Inoculation of Austenite Primary Grains in Cast Iron

51%

Kopyciński D. , Guzik E. , Szczęsny J. , Dorula J. , Siekaniec D. , Ronduda M.

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2014

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tom Vol. 14, iss. 4

45--48

EN

The modification is a widespread method of improving the strength properties of cast iron. The impact in terms of increasing amounts of eutectic grains has been thoroughly studied while the issue of the impact on the mechanical properties of primary austenite grains has not been studied in depth yet. The paper presents the study of both aspects. The methodology was to conduct the melting cast iron with flake graphite, then modifying the alloy by two sets of modifiers: the commercial modifier, and a mixture of iron powder with a commercial inoculant. The DAAS test was carried out to identify the primary austenite grains. The degree of supercooling was determined and the UTS test was performed as well. Additionally carried out the metallographic specimen allowing for counting grains. It can be concluded that the introduction of the iron powder significantly improved the number of austenite primary grains which resulted in an increase in tensile strength UTS.

13

Estimation of nuclei density in solidifying casting using the Kolmogorov theory

51%

Majchrzak E. , Dziewoński M. , Metelski A.

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tom R. 5, nr 15

253--258

EN

In the paper the solidification process in the micro-macro scale is analyzed. The mathematical model of heat transfer in the domain considered bases on the Mehl-Johnson-Avrami-Kolmogorov theory. The capacity of internal heat source resulting from the latent heat evolution is, among others, the function of nuclei density. This parameter is estimated using the methods of inverse problem solution. The additional information necessary in order to identify the unknown parameter results from the cooling curves at the selected points from casting domain. On the stage of numerical algorithm construction the least squares criterion containing the sensitivity coefficients is applied. The solution has been obtained using the boundary element method.

PL

W artykule analizowano proces krzepnięcia w skali mikro-makro. Model matematyczny przepływu ciepła w obszarze bazuje na teorii Mehla-Johnsona-Avrami-Kołmogorowa. Wydajność wewnętrznych źródeł ciepła związana z wydzielaniem się ciepła krzepnięcia jest zależna między innymi od gęstości zarodków. Oszacowanie tego parametru uzyskano rozwiązując zadanie odwrotne, w którym wykorzystano dodatkową informację dotyczącą przebiegu krzywych stygnięcia w kilku punktach odlewu. Algorytm bazuje na kryterium najmniejszych kwadratów, w którym występują tzw. współczynniki wrażliwości.