|Andrzej Gazda, Zbigniew Górny, Stanisława Kluska-Nawarecka, Henryk Połcik, Małgorzata Warmuzek|
Comparative studies were made on modification of aluminium CuAl10Fe3Mn2 bronze by application of modifiers affecting changes in surface properties (Na, K, Ca, Mg) and providing additional substrates for crystallisation (Zr, Ti, B). The results of structure examinations (optical microscope and scanning electron microscope), solidification kinetics analysis (thermal analysis), dilatometry, calorimetry, and mechanical tests were used.
Keywords: comperative studies, aluminium bronzes, modification, solidification, mechanical properties, structure,
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Piotr Dudek, Aleksander Fajkiel, Tomasz Reguła, Krzysztof Saja
As expected, the increasing demand for magnesium alloy castings has already become a fact. Considering this situation, a rich program of the studies on this particular subject has been initiated and put into operation at the Foundry Research Institute. The studies mainly include the development of new alloys along with the technologies of their casting. A good example are here the ultralight alloys (e.g. magnesium-lithium alloys). The addition of special alloying elements requires the development of new and original melting and casting technologies. Various investigations are also carried out on the new melt protecting and refining techniques. The present article comprises the results of the studies carried out recently by the Department of Non-Ferrous Metals operating in the Foundry Research Institute in Cracow. The aim of the studies was to develop for magnesium alloys and respective composite materials a complex technology ofmolten metal treatment and casting into the sand and metal moulds, followed by heat treatment. The program of the studies has been divided into several stages; the first stage was related with the technology of molten magnesium alloys treatment and refining. Complex studies covered only one alloy, i.e. AZ91, since in the family of magnesium alloys this one is the most popular and most widely used; it can be cast equally well into sand moulds and metal moulds by both pressure and gravity process. At the first stage of the investigations, the technology of melting and melt protection from the selfignition was developed. The effect of the gas mixture of a new composition on the refining process during casting into sand and metal moulds was examined. The effectiveness was determined from the macro- and microstructure density.
Keywords: magnesium alloys, technology of magnesium alloy melting, refining of magnesium alloys,
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Andrzej Gwiżdż, Zenon Pirowski, Stanisław Pysz, Robert Żuczek, Piotr Dworak
The study forms a part of the program of applied industrial research executed under Target Project No. ROW-II-403/2008 at MAGNUS-NORD Sp z o.o in Toruń. Pouring and solidification of two large steel castings weighing 200 kg (casting I) and 700 kg (casting II) was simulated, basing on the casting manufacturing technology used up to now. Detailed analysis of the results of simulation resulted in changes proposed and introduced to the so far used manufacturing technology. After the said changes had been introduced, the simulation of the casting process was done once again. The analysis of the obtained results indicated a substantial improvement in the solidification conditions and effectively eliminated the porosities and shrinkage cavities.
Keywords: simulation, pouring process, solidification, porosity, casting defects,
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Janusz Faber, Maria Żmudzińska, Mariola Latała-Holtzer
In view of the documented pathogenic effect on human health of dust containing crystalline silica, an attempt has been made to identify different variations of polymorphic silica in samples of dust emitted from foundries using sand moulds. The polymorphic variations of SiO2 (qualitative phase analysis) were examined by the X-ray diffraction method (the Debye-Sherrer-Hull powder method [DSH]). The samples were taken in a selected foundry at different distances from the source of emission. In the samples of falling and suspended dust, the low- and high-temperature variations of SiO2 accompanied by metallic phases, were identified.
Keywords: crystal silica, DSH powder method, dust, metallic phases,
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