|Zbigniew Górny, Stanisława Kluska-Nawarecka, Krzysztof Saja|
The effect of solution heat treatment with jet cooling and modification with C + Ca and CaC2 on the behaviour of BA1044 alloy in as-cast state, and after solution heat treatment and toughening was examined. The microjet modification and solution heat treatment are clearly beneficial for the Rp0,2 in quenched and tempered state. High-temperature annealing enables obtaining higher plastic properties, while low-temperature annealing improves the mechanical properties.
Keywords: aluminium bronze, modification, aging, heat treatment, mechanical properties,
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Tomasz Reguła, Piotr Dudek, Aleksander Fajkiel
This paper presents the results of research work related with the effect of calcium on the microstructure and mechanical properties of AZ91 alloy. Samples of appropriately prepared alloy grades containing the addition of calcium in different concentrations (from 0.1 to 2.5 wt%) were examined in a static tensile test at room temperature and at elevated temperatures (150°C). Examinations of the microstructure were also carried out and DSC curves were plotted. It was found that, compared to the base AZ91 alloy, with increasing calcium concentration, the tensile strength at elevated temperatures increases, too. This effect is due to replacement of the low-melting Mg17Al12 phase with calcium-containing phases like Al2Ca and (Mg, Al)2Ca and to enrichment of the interdendritic spaces with Ca. At the same time, the addition of calcium adversely affects the mechanical properties at room temperature, which can be explained by brittleness of the Mg-Al-Ca phases.
Keywords: magnesium alloy, alloying addition, calcium, mechanical properties, microstructure,
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Artur Kudyba, Aleksandra Siewiorek, Natalia Sobczak
The aim of this study was to determine the effect of temperature and zinc content on the solderability of nickel substrates with liquid Sn-xZn alloys (4.5, 90, 95 wt% Zn). Solderability tests were carried out by the wetting balance method which allows the measurement of wetting force and wetting time and determination of the contact angle size. The study was performed at two different temperatures applied to each of the examined alloys, i.e. for Sn-4.5Zn at 230 and 250°C, for Sn-90Zn at 400 and 450°C, and for Sn-95Zn at 410 and 450°C. After the solderability tests, structural analysis was performed on sample cross-sections using optical microscopy and scanning electron microscopy coupled with energy dispersive spectroscopy for chemical analysis. It was found that temperature increase improves the solderability in each of the systems investigated. With process temperature raised to 450°C for alloys with 90 and 95 wt% Zn, a complete wetting of the tested nickel substrates was obtained (the value of contact angle θ = 0°).
Keywords: lead free solder, Sn-Zn, wetting balance test, solderability, wetting balance curve, contact angle,
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Adam Klasik, Jerzy J. Sobczak, Krystyna Pietrzak, Andrzej Gazda, Natalia Sobczak
This article presents the results of research on selected thermophysical properties of the commercial F3S.10S, F3S.20S, F3S.30S metal matrix composites (MMCs) based on the Al359 alloy matrix reinforced with SiC particles added in an amount of 10 vol%, 20 vol% and 30 vol%, respectively. The composites were subjected to the repeated process of remelting (9 remelts altogether). Changes in the coefficient of linear expansion and thermal diffusivity were determined in function of the reinforcing phase content and number of the successively repeated remelting operations. It has been proved that the increasing content of the reinforcing phase causes a decrease in the coefficient of thermal expansion, whereas the nine times repeated remelting operation does not change in any major way these values. It was also stated that temperature increase was responsible for a significant decrease of the thermal diffusivity of the investigated materials.
Keywords: aluminum composites, thermophysical properties, coefficient of linear expansion, thermal diffusivity, multiple remelting, recycling,
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Krystyna Pietrzak, Adam Klasik, Katarzyna Makowska, Jerzy J. Sobczak, Andrzej Wojciechowski, Dariusz Rudnik
The study adresses the problem of the damping capacity of metal matrix composites based on A359 alloy reinforced with 10%, 20% and 30% SiCp, subjected to multiple remelting. The aim of the research was to prove that the recycling process simulated by multiple remelting does not significantly change the damping characteristics of the investigated materials. Based on the results obtained it was possible to ascertain that the specific character of the SiCp / metal matrix interface is the main feature affecting the damping capacity of these materials. At the same time, it should be stressed that the properties of the SiCp / metal matrix interface depend greatly on the manufacturing method. Strong bond produced between the reinforcing phase and composite matrix guarantees optimum mechanical characteristics at the expense of reduced damping capacity. The results confirm the potential possibilities of introducing to industrial practice the solution offered by the recycling process, which is a simple and economically effective method carried out by multiple remelting. However, efforts should focus on minimization of gas-shrinkage porosity during the successive casting operations to avoid the deterioration of mechanical characteristics.
Keywords: aluminum matrix composites, damping capacity, remelting, recycling,
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Piotr Długosz, Paweł Darłak, Włodzimierz Bochniak
The paper presents the results of examinations of composite samples in which the reinforcement is waste fly ash from power plants, while matrix is aluminum (99,98 wt.%). The agglomerates of master composite obtained by mechanical alloying were subjected to hot plastic consolidation to transform the powder into a solid material, and thus formed compacts were heated to a temperature of 350-400°C and extruded by KOBO® method. The obtained cylindrical samples were analyzed by computed tomography, which revealed a satisfactory level of the distribution of the reinforcing phase at a 25 wt.% fly ash concentration, and absence of the areas characterized by too high concentration of ceramic particles, which may act as a source of the adverse phenomenon of agglomeration. An improvement in the mechanical properties of composite samples was achieved compared with the sole matrix material.
Keywords: fly ash, ALFA® composites, KOBO® method,
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Krzysztof Jaśkowiec, Waldemar Uhl
Melting of cast steel based on Fe-Al system was described. Problems of technological nature related with the melting process performance, starting with computer simulation and in the casting treatment ending, were discussed. The outcome of the study was designing and making of castings for high temperature operation. In addition to practical observations, attention was focussed on the development of methods to reduce to minimum the loss of Al and on the methods to make castings without the defects typical for this type of cast iron or cast steel. Another object of discussion was hardness and impact resistance of alloys based on Fe-Al.
Keywords: FAP, high-aluminium cast steel, Fe-Al, aluminium loss, hardness, impact resistance,
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Andrzej Gwiżdż, Robert Żuczek, Mieczysław Nowak
Numerical analysis was carried out to establish the operating stress distribution in softsealed gate valves cast from ductile iron EN-GJS-400-15 for the gas network of PE pipes. The analysis was carried out with ANSYS software, based on data and documentation of actual test conditions used at the JAFAR SA Fittings Factory. The use of ANSYS software allowed integration between the results of numerical analysis of the developed virtual structure loaded with test pressure and the response of real structure obtained during laboratory tests carried out on a stand for pressure leak testing, with further possibility of a verification of the results, both virtual and real. This publication presents the results of the analysis carried out on DN50 and DN150 gate valves. Through dimensional corrections introduced to the design, the results of this analysis will be used in verification of castings operating as components in models of the wedge gate valves.
Keywords: computer-aided foundry production, simulation of stress distribution, cast iron fittings,
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Krystyna Rabczak, Paweł Wojnarowski
The paper presents a range of functionality of a copyright application, the main objective of which was to create an information database and the database management system. The system was developed for the implementation of strategies to optimize sharing of resources stored in diverse databases operating at the Institute. The other functionality is optimal server power allocation for computing tasks performed by individual departments. The new software will allow the best use of available resources, combined with simultaneous environment optimization. It will make possible adaptation of the storage conditions to the new scientific knowledge databases created in research departments of the Foundry Research Institute. The system will enable optimum management of the Institute IT infrastructure and fully efficient use of the IT staff work time.
Keywords: software, databases, information, management, IT,
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Tomasz Reguła, Piotr Dudek
This paper presents the results of research on an impact of external pressure applied in the squeeze casting process on the structure of PA9 alloy. Samples for the research were obtained by casting the tested PA9 alloy into a die under a varying pressure of 0.1 (atmospheric), 75 and 150 MPa, using an UBE VSC 500 squeeze casting machine. A significant effect of pressure on the average grain size and other microstructural characteristics was stated, proving the usefulness of liquid-phase methods using external pressure in the improvement of casting quality.
Keywords: aluminium alloy, PA9, squeeze casting, squeeze pressure, microstructure,
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