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1

Microscopic Analysis of the Aluminium Castings Produced with the use of Polymer Composite Patterns

Czarnecka-Komorowska Dorota, Gawdzińska Katarzyna, Popielarski Paweł

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 3

113--117

EN

The paper presents a microscopic analysis of the surface and fracture of aluminium castings produced using the lost-wax method for patterns made of a composite material, i.e. polyethylene with the addition of bentonite. Castings are made of AlSi7 aluminium alloy (silumin) in a plaster mould. A new type of polymer waxes enriched with bentonite was used to obtain new composites, minimizing the defects caused by the casting production process. The castings were made in the centrifugal casting process. The prepared plaster moulds were removed from the furnace and poured with liquid aluminium alloy (AlSi7) at 750°C. The surface and fracture of the castings was analysed using an optical digital microscope type VHX-7000 manufactured by KEYENCE. It has been proven that the studied castings feature surface defects (raw surface defects) in the form of high roughness and the presence of bentonite inclusions classified as casting contamination. During the tests, shape defects related to mechanical damage were also.

2

Investigation of Particle Filtration in Aluminium Alloy

Baumann Benedict, Keßler A., Hoppach E., Wolf G., Szucki M., Hilger O.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

70--80

EN

The objective of this work is to gain a deeper understanding of the separation effects and particle movement during filtration of non-metallic inclusions in aluminum casting on a macroscopic level. To understand particle movement, complex simulations are performed using Flow 3D. One focus is the influence of the filter position in the casting system with regard to filtration efficiency. For this purpose, a real filter geometry is scanned with computed tomography (CT) and integrated into the simulation as an STL file. This allows the filtration processes of particles to be represented as realistically as possible. The models provide a look inside the casting system and the flow conditions before, in, and after the filter, which cannot be mapped in real casting tests. In the second part of this work, the casting models used in the simulation are replicated and cast in real casting trials. In order to gain further knowledge about filtration and particle movement, non-metallic particles are added to the melt and then separated by a filter. These particles are then detected in the filter by metallographic analysis. The numerical simulations of particle movement in an aluminum melt during filtration, give predictions in reasonable agreement with experimental measurements.

3

Reliability evaluation in the production process of aluminum castings

Jankajova E., Kotus M.

Production Engineering Archives

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2015

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Vol. 6, No. 1

49--51

EN

This article deals with reliability evaluation of the production process for die casting. Reliability of the production process was assessed on the basis of productivity and deformity. With suitably chosen production technology the increasing of labour productivity can be achieved alongside the required quality of aluminum castings.

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Metallostatic pressure function in the quality of Al-Si alloy castings made in sand moulds

Zych J., Wójcik M., Kolczyk J., Snopkiewicz T.

Metallurgy and Foundry Engineering

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2014

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Vol. 40, no. 3

191--202

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

5

Centrifugal Castings Locally Reinforced with Porous Al2O3 Preform

Dolata A. J.

Archives of Metallurgy and Materials

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2014

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Vol. 59, iss. 1

345--348

EN

The main objective of presented researches were tests of infiltration of the porous ceramic preforms at the pressure in centrifugal casting process. Make an assumption that the porous preform will be create the local reinforcement layer in specific area of the casting. For investigations the alumina porous ceramic preforms were applied (Al2O3). The pressure to infiltrate molten aluminum alloy into ceramic preforms was generated by centrifugal force. The structure of composites was examined by light and electron microscope. The investigations of composites microstructure exhibited high degree of infiltration of spherical macropores in Al2O3 ceramic preforms by the molten aluminium alloy. On the basis of structural studies has been shown that centrifugal force is effective as a driving force for the infiltration of porous preforms.

PL

Głównym celem przedstawionych badań była próba infiltracji porowatych preform ceramicznych wspomagana ciśnieniem generowanym w procesie odlewania odśrodkowego. Założono, że porowata pretorma będzie tworzyć lokalne wzmocnienie w określonym obszarze odlewu. W badaniach wykorzystano preformy ceramiczne (Al2O3). Ciśnienie niezbędne do infiltracji ceramicznej preformy ciekłym stopem aluminium było generowane za pomocą siły odśrodkowej. Strukturę kompozytu badano z wykorzystaniem mikroskopii świetlnej i elektronowej. Badania mikrostruktury kompozytów wykazywały wysoki stopień infiltracji sferycznych makroporów preformy Al2O3 przez stop aluminium. Na podstawie badań strukturalnych wykazano, że siła odśrodkowa działa jako siła napędowa i wspomaga proces infiltracji porowatych preform.

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Odlewy aluminiowe w budowie samochodów

Kanikuła Z.

Przegląd Odlewnictwa

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1999

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Vol. 49, z. 1

30-32

PL

Stopy aluminium są tworzywem coraz szerzej stosowanym w budownictwie pojazdów mechanicznych. Tendencja ta jest wynikiem wymagań i warunków stawianych przez konstruktorów i producentów pojazdów oraz stałego rozwoju w dziedzinie technologii odlewniczych. Omówiono aktualny stan i tendencje rozwojowe w zakresie stosowania tych tworzyw na części pojazdów.

EN

Aluminium alloys are the material more and frequently used in the construction of motor vehicles. This trend is the result of growing demands and conditions put forward by car producers and designers as well as of the constant development of foundry technologies. The present state and the development trends in the field of application of aluminium alloys for car parts are presented.