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EN
The use of environmentally friendly inorganic binders and new technologies for cores production is widely discussed topic in recent years. This paper contains information about new hot curing process for core making with alumina-silicate based inorganic binders – geopolymers. Main differences between hot cured geopolymers and hot cured alkali silicate based inorganic binders are discussed. The main objective of this research paper was to investigate basic technological properties of geopolymer binder system such as strength, compaction, storage ability and knock-out properties. For this purpose, three mixtures with different powder additives were prepared and tested in laboratory conditions using specific methods. Strength properties evaluation showed sufficient levels as well as knock-out properties measurement, even with additives B and C originally designed for the use with alkali silicate based two component binder systems. Additives B and C were considered compatible with geopolymer binders after casting production trial results. Storage ability of geopolymers seems to be more sensitive than of alkali silicate based binders in the same tested conditions. Mixtures with geopolymer binder showed 20% more decrease of strength compared to alkali silicate binders after 24 hours in conditions of 25 °C and 65 %RH.
2
Content available FSW Welding of Aluminium Casting Alloys
EN
The article contains basic information associated with the impact of the FSW process parameters on the forming of a weld while friction welding of aluminium casting alloys. Research was conducted using specially made samples containing a rod of casting alloy mounted in the wrought alloy in the selected area of FSW tool acting. Research has thrown light on the process of joining materials of significantly dissimilar physical properties, such as casting alloys and wrought alloys. Metallographic testing of a weld area has revealed the big impact of welding conditions, especially tool rotational speed, on the degree of metal stirring, grain refinement and shape factor of a weld. As the result of research it has been stated that at the high tool rotational speed, the metals stirring in a weld is significantly greater than in case of welding at low rotational speeds, however this fails to influence the strength of a weld. Plastic strain occurring while welding causes very high refinement of particles in the tested area and changing of their shape towards particles being more equiaxial. In the properly selected welding conditions it is possible to obtain joints of correct and repeatable structure, however in the case of the accumulation of cavities in the casting alloy the FSW process not always eliminates them.
EN
The paper presents results of the studies regarding influence of metallostatic pressure of AlSi7Mg alloy on surface roughness of castings prepared in sand moulds as well as on alloy's density. Castings in a cylindrical shape with a diameter of 15.0; 25.0 or 3.5 mm and height of 700 mm that were cast in a vertical orientation are investigated. The melted alloy was poured into moulds in two ways: bottom up, and top down. Higher pressure and larger diameter of castings favors increase of surface roughness. In the analyzed range of height of a metal column, density increases linearly: for instance, in case of castings with diameter of 025 mm, the density increases from p = 2.60 g/cm3 to p = 2.68 g/cm3, what is about 0.10 g/cm3. In the roller with larger diameter, the density is slightly smaller, howeverthe range of changes along the longer axis is similar to that in the cylinder with diameter of 025 mm. Additional, ultrasonic studies were performed, which prove that with smali changes of the alloy density, velocity of a longitudinal wave changes only slightly.Thus, it is difficult to control smali variations (Δp < 0,10 g/cm3) in density of AISi7Mg alloy with ultrasonic technique.
PL
W pracy przedstawiono wyniki badań wpływu ciśnienia metalostatycznego stopu AlSi7Mg na chropowatość powierzchni odlewów wykonywanych w formach piaskowych oraz na gęstość stopu. Badaniami objęto odlewy w kształcie walca o średnicach d = 15.0; 25.0 i 3.5 mm i wysokości h = 700 mm wykonywanych w pozycji pionowej. Formy zalewano na dwa sposoby: od dołu i od góry. Chropowatość powierzchni zwiększa się przy wyższych wartościach ciśnienia oraz wraz ze zwiększeniem grubości odlewów. W badanym zakresie zmian wysokości słupa metalu gęstość zwiększa się w sposób liniowy. Przykładowo dla odlewów o średnicy 025 mm gęstość rośnie od p = 2.60 g/cm3 do p = 2.68 g/cm3, o niecałe 0.10 g/cm3. W grubszym wałku gęstość jest nieco mniejsza, a zakres zmian na wysokości jest podobny jak w wałku 025 mm. Dodatkowe badania ultradźwiękowe pozwalają stwierdzić, iż przy tych niewielkich zmianach gęstości stopu, prędkość fali podłużnej zmienia się w niewielkim stopniu. Techniką ultradźwiękową trudno jest kontrolować niewielkie zmiany (Δp < 0,10 g/cm3) gęstości stopu AlSi7Mg
4
Content available remote The skeleton castings as a new type of cast lattice structures
EN
Purpose: of this paper is to present selected achievements in field of new type material - skeleton structures. Actual state of knowledge about periodic cellular materials was described. The aim of this work is to show results about mechanically optimised skeleton casting with octahedron topology. Correctness of technological parameters was investigated by microstructural research. Most important parameters of the manufacturing process were identified. Design/methodology/approach: The influence of technological parameters to the microstructure in different points of casting was described. Simulations of the mould filling processes were also carried out. Real experiments were performed to prove the simulation results. The qualitative and quantitative metallographic analysis was also carried out. Findings: It was found that the octahedron shape of internal cell causes best stress distribution and that the skeleton castings are a good alternative for cellular materials such as metal foams, lattice structures or sandwich panels. Research limitations/implications: Casting methods used to manufacture materials such as described skeleton castings confirmed their usefulness. Not well known and used yet rheological properties of liquid metals allow obtaining shape complicated structures near to metallic foams but with periodic structure. Practical implications: Technological parameters of the skeleton castings manufacturing process were developed. Without use of advanced techniques there is a possibility to manufacture relatively low cost skeleton structures in a typical foundry. Originality/value: Three dimensional cast skeleton structures with internal topology of octahedron confirmed their usefulness as elements used for energy dissipation. Obtaining the homogenous microstructure in the whole volume of complicated shape castings can be achieved.
EN
A comprehensive understanding of melt quality is of paramount importance for the control and prediction of actual casting characteristics. Among many phenomenons that occur during the solidification of castings, there are four that control structure and consequently mechanical properties: chemical composition, liquid metal treatment, cooling rate and temperature gradient. The cooling rate and alloy composition are among them most important. This paper investigates the effect of some major alloying elements (silicon and copper) of Al-Si-Cu alloys on the size of the secondary dendrite arm spacing. It has been shown that both alloying elements have reasonable influence on the refinement of this solidification parameter.
6
Content available Materiały ogniotrwałe dla przetwórstwa aluminium
PL
Omówiono procesy korozyjne materiałów glinokrzemianowych w kontakcie ze stopami aluminium i określono sposoby zwiększenia trwałości materiałów ogniotrwałych stykających się z ciekłym metalem. Przedstawiono wyniki badań dotyczące opracowania betonu ogniotrwałego z udziałem szkła kwarcowego do rynien transportowych i wyłożeń urządzeń w ciągach technologicznych stosowanych w przetwórstwie aluminium, w szczególności w urządzeniach do ciągłego, poziomego odlewania aluminium. Zaprezentowano również wyniki badań nad opracowaniem formowanych izostatycznie rur do niskociśnieniowego odlewania aluminium z osnową sialonową, otrzymywanych na drodze reakcyjnego spiekania.
EN
Corosion processes of aluminosilicate materials on the contact with melted aluminium were desribed and the methods of increasing the time of service of refractories in such contact were determined. The results of investigation on fused silica containing refractory castables for runers and linings for aluminium casting processes as well as on isostaticaly pressed tubes with sialon matrix for low pressure aluminium casting process obtained by reaction sintering have been presented.
7
Content available remote Qualification of welding procedures for aluminium, steel and iron castings
EN
The article presents the qualification process concerned with the following procedures: finishing welding of aluminium castings pursuant to PN-EN ISO 15614-4, production welding of steel castings pursuant to PN-EN ISO 11970 and production- and finishing welding of cast irons pursuant to PN-EN ISO 15614-3. The work enumerates the cases of qualification of welding procedures for aluminium, steel and iron castings and presents details related to test joint designs as well as the manner of their preparation taking into account welding conditions and other technological aspects. The text also contains precise characteristics of test joint examinations and their range of application while qualifying a given welding procedure. In addition, the article informs about test results which justify the qualification of a finishing welding procedure for aluminium castings and test plate butt joints in case of cast irons and cast steels. In all cases particular attention was paid to the range of qualification of procedures for characteristic conditions of the welding process and its basic variables.
EN
The primary target of this project consists of combining the technique of rapid prototyping and casting to produce aluminum parts in a sand mold being made the corresponding models and core boxes by means of the technology of rapid tooling, FDM (fused deposition modeling) of ABS. The followed process to obtain the pieces is casting, that consists of the fused metal spill in a mold pattern previously conformed, followed of a cooling and later rinding of the solidified piece. The models and core box, generally, is made in wood or plaster, but in this case they were made by means of a Rapid prototyping machine of the company 3Ddimension. The phase of design and manufacture of the model and the mold are most expensive and critical of the process. In this work it is tried to study the valuation of the time of manufacture of the models, core box and molds. The application Catia V5 R17 has been used for the geometric definition of the model and care box. This model is exported in stereolithography format (stl) and after this, the file was sent to the printer Dimension BST 768 and begin the construction of the models. The proposal methodology using rapid prototyping to generate the models is a clean and fast solution, and in addition it allows to obtain geometries that are nonviable by another procedure. The surface finish quality of the model is appropriate for the casting process, and reproduces with a high reliability the model CAD.
PL
Od kilku lat, zarówno w Polsce, jak i w świecie, wzrasta zapotrzebowanie na wyroby aluminiowe, które z powodzeniem zastępują m.in. wyroby stalowe i tworzywa sztuczne, głównie w przemyśle motoryzacyjnym i w budownictwie. Zmienia się również, zgodnie z ogólnymi tendencjami światowymi, struktura produkowanych stopów obejmująca z jednej strony materiał wsadowy w postaci gąsek aluminium pierwotnego lub jego stopów, z drugiej złom poamortyzacyjny. Ten ostatni wykazuje znaczne zróżnicowanie, zarówno w odniesieniu do rodzaju, jak i wielkości kawałków oraz stopnia zanieczyszczenia. Wpływa to wyraźnie na ilości wytwarzanych zgarów, powstanie związków typu spineli, niebezpieczeństwo uszkodzenia wymurówki podczas załadunku pieca i duże zmiany temperatury. Wszystkie te czynniki negatywnie działają na trwałość materiałów ogniotrwałych i tym samym wyznaczają kierunki ich rozwoju pod kątem wzrostu odporności, m.in. na korodujące działanie płynnego metalu. W referacie zostaną przedstawione zmiany, jakie zachodzą w technologii materiałów ogniotrwałych, uwzględniające zmienione warunki, zarówno w strukturze topienia aluminium, jak i jego przetwórstwie. Uwzględnione zostaną nowe materiały ogniotrwałe, jakie wchodzą w ostatnim okresie do eksploatacji w nowoczesnych procesach przetwórczych, w tym na linii ciągłego poziomego odlewania aluminium oraz w metodzie niskociśnieniowego odlewania. Przedstawione zostaną nowe tendencje w zakresie wyłożeń monolitycznych (głównie piece topielne), prefabrykatów betonowych o zwiększonej odporności na działanie metalu (elementy wchodzące w skład linii poziomego ciągłego odlewania) oraz wyrobów formowanych zwartych z uwzględnieniem nowych rodzajów wiązań tworzyw ceramicznych i nowych rozwiązań technologicznych.
EN
From several years in Poland as well as in other countries the demand for aluminium articles, which replace steel or plastic in automotive and construction industries has been systematically increasing. According to the general trends the structure of produced alloys has been changing including both: batch of initial aluminium ingots (and its alloys) and aluminium scrap processing. In the second case significant differentiation concerning the type, dimensions and contamination level of used metal scrap is observed and may be strictly connected with amount of generated melting loss, formation of spinel-like compounds, possibility of the refractory lining failure during furnace loading and large temperature fluctuations. All mentioned above factors act negatively on refractory materials reliability and set new directions for development concerning the increase of corrosion resistance of material with among other liquid metal as a corrosive agent. In this report progress in refractory materials considering the changed conditions of melting and processing of aluminium is presented. New refractory materials introduced lately to modern metallurgical systems comprise products used in horizontal line of continuous casting and in low-pressure casting. New tendencies in case of monolithic linings (smelting furnaces), prefabricated castables with increased corrosion resistance (elements used in continuous casting line) and shaped ceramic products with new kinds of bonding systems and technological solutions will be presented.
10
Content available remote Stanowisko do badania skurczu liniowego i naprężeń skurczowych w odlewach
PL
Opisano stanowisko do badania ewolucji skurczu liniowego i naprężeń skurczowych w odlewie. Zastosowano mikroprocesorową rejestrację sygnałów pomiarowych. Przedstawiono przykładowe ilustracje zmian skurczowych w aluminium.
EN
A stand for examination of the development of linear contraction and shrinkage stresses in casting has been described. The microprocessor recorder has been used for registering of measure signals. Exemplary results of linear contraction development in aluminum have been presented.
EN
In the paper the boundary element method using discretization in time is applied for numerical simulation of aluminium casting solidification. The energy equation describing the process contains a term called the source function. The capacity of this function results from the considerations known in literature as the macro/micro approach. The results of computations presented in the final part of the paper have been experimentally verified.
PL
W pracy wykorzystano metodę elementów brzegowych z dyskretyzacją czasu do numerycznej symulacji krzepnięcia odlewu aluminiowego. W równaniu energii opisującym proces krzepnięcia występuje składnik nazywany funkcją źródła. Wydajność tej funkcji wynika z rozważań znanych w literaturze pod nazwą modelu makro/mikro. W końcowej części pracy przedstawiono wyniki obliczeń numerycznych, które zostały zweryfikowane doświadczalnie na odlewie próbnym.
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