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1

System odlewniczy korund/nano Al,2O3. Część 1: właściwości surowców formierskich

Wiśniewski Paweł

Szkło i Ceramika

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2023

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R. 74, nr 1

24--30

PL

W artykule przedstawiono wyniki badań proszku korundowego oraz spoiwa formierskiego zawierającego nanometryczny Al2 O3 (Evonik) o średnicy 16 nm. W ramach prac badano m.in. morfologię SEM proszku, TEM spoiwa, skład chemiczny, wielkość cząstek oraz potencjał zeta. Dodatkowo spoiwo scharakteryzowano gęstością, pH, zawartością fazy stałej, parametrami sterologicznymi oraz lepkością względną. Stwierdzono, że zastosowanie obu tych surowców jako nowego systemu formierskiego jest perspektywiczne z uwagi na zgodność chemiczną oraz właściwości.

EN

The paper presents the results of investigation on corundum powder and molding binder containing nanometric Al2O3 (Evonik) with the diameter of 16 nm. Powder SEM morphology, binder TEM morphology, chemical composition, particle size and zeta potential have been studied. The binder was also characterized by density, pH, solid phase content, sterological parameters and relative viscosity. It was found that the use of both of these raw materials as a new molding system is prospective due to chemical compatibility and their properties.

2

Investment Casting of AZ91 Magnesium Open-Cell Foams

Kapłon Honorata, Dmitruk Anna, Naplocha Krzysztof

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

11--16

EN

The process of investment casting of AZ91 magnesium alloy open-cell porosity foams was analysed. A basic investment casting technique was modified to enable the manufacturing of magnesium foams of chosen porosities in a safe and effective way. Various casting parameters (mould temperature, metal pouring temperature, pressure during metal pouring and solidifying) were calculated and analysed to assure complete mould filling and to minimize surface reactions with mould material. The foams manufactured with this method have been tested for their mechanical strength and collapsing behaviour. The AZ91 foams acquired in this research turned out to have very high open porosity level (>80%) and performed with Young’s modulus of ~30 MPa on average. Their collapsing mechanism has turned out to be mostly brittle. Magnesium alloy foams of such morphology may find their application in fields requiring lightweight materials of high strength to density ratio or of high energy absorption properties, as well as in biomedical implants due to magnesium’s high biocompatibility and its mechanical properties similar to bone tissue.

3

Ocena wad spoiw odlewniczych

Wiśniewski Paweł

Szkło i Ceramika

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2022

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R. 73, nr 4

30--33

PL

W artykule przedstawiono zagadnienia związane z problemem stosowania wadliwych spoiw powodujących powstawanie wad ceramicznych form odlewniczych w procesie odlewania precyzyjnego. Opracowano i opisano metodykę oceny przegrzanych i przemrożonych spoiw. Metodyka analityczna polegała na badaniach spoiw formierskich, które zostały poddane ocenie wizualnej, pomiarom mętności, pomiarom lepkości i pH oraz badaniom napięcia powierzchniowego. Przedstawiono wyniki dla dwóch rodzajów spoiw: zawierających koloidalny SiO2 (LUDOX AM) oraz nanometryczny Al2O3 (EVONIK W640 ZX).

EN

The paper presents topics related to the problem of using defective binders in investment casting process. A methodology for the assessment of overheated and frozen binders was developed and described. The analytical methodology consists in testing the binders through: visual evaluation, turbidity measurements, viscosity measurements, pH and testing the surface tension of binders containing colloidal SiO2 (LUDOX AM) and nanometric Al2O3 (EVONIK W640 ZX).

4

Mechanical and Thermal Properties of Aluminum Foams Manufactured by Investment Casting Method

Dmitruk Anna, Kapłon H., Naplocha K.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 1

37--42

EN

A method for the open-cell aluminum foams manufacturing by investment casting was presented. Among mechanical properties, compressive behaviour was investigated. The thermal performance of the fabricated foams used as heat transfer enhancers in the heat accumulator based on phase change material (paraffin) was studied during charging-discharging working cycles in terms of temperature distribution. The influence of the foam on the thermal conductivity of the system was examined, revealing a two-fold increase in comparison to the pure PCM. The proposed castings were subjected to cyclic stresses during PCM’s subsequent contraction and expansion, while any casting defects present in the structure may deteriorate their durability. The manufactured heat transfers enhancers were found suitable for up to several dozen of cycles. The applied solution helped to facilitate the heat transfer resulting in more homogeneous temperature distribution and reduction of the charging period’s duration.

5

Investment Castings of Magnesium Alloys: A Road Map and Challenges

Vyas Akash V., Sutaria M. P.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

19--23

EN

In the manufacturing sector, the processing of magnesium alloys through the liquid casting route is one of the promising methods to manufacture automotive and aircraft components, for their excellent mechanical properties at the lower weight. Investment casting process has the great cabaility to produce near net shape complex castings for automotive and aircraft applications. The distinct and attractive engineering properties of magnesium alloys have shown to be promising in terms of its potential to replace materials such as cast iron, steel, and aluminum In this regard, the efforts to develop processing technology for these alloys for their wide range of applications in industries have been reported by the scientific and engineering community. For successful production of magnesium alloy castings, it requires specialized foundry techniques because of the particular chemical and physical properties of magnesium; especially the reactive and oxidative nature of these alloys. The industry is young enough, to tap the potential.

6

Cast Structures Improving Thermalm Conductivity for Energy Storage

Raźny Natalia M.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

11--16

EN

Thermal energy encounters a huge demand in the world, part of which can be met by renewable energy sources, such as solar energy, and storage of thermal energy surplus from industrial processes. For this purpose, thermal energy storage (TES) units, in which heat is stored, are developed. The energy is accumulated by phase change materials (PCM) characterized by high phase transition enthalpy. PCMs have poor thermal conductivity; therefore, to take full advantage of their capabilities and to accelerate the charging and discharging cycle, metallic structures are used. These structures are manufactured using investment casting technology. Creating models with additive methods, such as 3D printing, allows obtaining complex shapes with high accuracy, such as thin-walled castings. At a large scale, the method may not be cost-effective. In this paper, the heat exchanger models were made from PLA and the castings - from AC44200 aluminum alloy. Investment casting requires the proper selection of parameters, such as the right material for the model, the selection of the firing temperature, the adjustment of the temperature of the molten metal, the temperature of the mold, and the pressure in it. Misaligning any of the parameters can lead to imperfections on the finished casting. Based on the model roughness study, it was found that minor roughness and higher accuracy are presented by the lower parts of the casting, while weaker performance is observed for the upper parts. Metal castings in a salt PCM environment may be subjected to corrosion. Therefore, the authors proposed to produce protective coatings on aluminum castings by the PEO method - plasma electrolytic oxidation. Porous ceramic thin films consisting mainly of alumina were obtained. The next tests will be aimed to confirm whether this layer will not negatively influence the thermal conductivity of the thermal energy storage.

7

Publisher Correction to: Characterization of the as-cast microstructure and selected properties of the X-40 Co-based superalloy produced via lost-wax casting

Rakoczy Łukasz, Grudzień-Rakoczy Małgorzata, Cygan Rafał, Rutkowski Bogdan, Kargul Tomasz, Dudziak Tomasz, Rząd Ewa, Milkovič Ondrej, Zielińska-Lipiec Anna

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 4

art. no. e170, 2022

EN

The thermodynamical simulation predicts the phase transformation of M7C3 to M23C6, proven previously via electron microscopy. Some other reported experimental works suggest that this can also take place also during heating [22, 45, 46]. Considering this, the melting process of the primary M7C3 carbide can be that the M7C3 first undergoes a phase transformation into M23C6 and then melts, instead of directly melting. A similar conclusion was given by Gui et al. [47-49] based on experiments on the Co-based superalloy strengthened (in as-cast condition) by M7C3 and MC carbides. It was suggested that the creation of the liquid phase follows the reaction M23C6 + α→L. The reaction was initiated on the M23C6/α interface and proceeded towards the center in the range of 1280 - 1348 ˚C. Before melting, the MC eutectic carbide degenerated, and its morphology changes to a well-rounded shape. Exceeding 1400 ˚C leads to the melting reaction of MC + α→L in the X-40 Co-based superalloy.

8

Characterization of the as‑cast microstructure and selected properties of the X‑40 Co‑based superalloy produced via lost‑wax casting

Rakoczy Łukasz, Grudzień-Rakoczy Małgorzata, Cygan Rafał, Rutkowski Bogdan, Kargul Tomasz, Dudziak Tomasz, Rząd Ewa, Milkovič Ondrej, Zielińska-Lipiec Anna

Archives of Civil and Mechanical Engineering

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2022

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Vol. 22, no. 3

art. no. e143

EN

The X-40 Co-based superalloy is often used in the aerospace industry directly in as-cast condition and its analysis in this state is essential to understand further possible phase transformations during service. With this in mind, this work focuses on characterizing the material’s as-cast microstructure, phase transformation temperatures and oxidation resistance. Observations and analyses were performed via thermodynamic simulations, X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), scanning-transmission electron microscopy (STEM-HAADF), energy-dispersive X-ray spectroscopy (EDX), dilatometry (DIL) and differential scanning calorimetry (DSC). The microstructure of the dendritic regions consisted of the α matrix, with MC, M7C3 and M23C6 carbides being present in the interdendritic spaces. Based on DIL, it was found that precipitation of the Cr-rich carbides from the saturated α matrix may occur in the range 650-750 °C. DSC determined the incipient melting and liquidus temperatures of the X-40 superalloy during heating to be 1405 °C and 1421 °C, respectively. Based on oxidation resistance tests carried out at 860 °C, it was found that the mass gain after 500 h exposure was 3 times higher in the air than in steam.

9

Effect of Ti on Selected Properties of AlSi7Mg0.3Cu0.5 Alloy with Constant Addition of Zr

Bolibruchová D., Kuriš M., Matejka M., Major-Gabryś K., Vicent M.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 1

65--72

EN

The article is focused on the synergic effect of constant content of Zr and higher content of Ti on mechanical properties Al-Si alloy. The Ti additions were in proportions of 0.1, 0.2 and 0.3 wt.% Ti. The casting process was carried out in ceramic molds, created for the investment casting technology. Half of the experimental samples were processed by precipitation curing T6. The measured results were compared with primary alloy AlSi7Mg0.3 and experimental alloy AlSi7Mg0.3Cu0.5Zr0.15. In variant with addition 0.1 wt. %, the tensile strength Rm increased by 1,5% but the elongation AM decreased to 40%. Variants with 0.2 and 0.3 wt. % addition of Ti achieved similar Rm but approximately 40% decrease in AM. However, it is interesting that yield strength Rp0.2 increased for all variants by approximately 14 to 20%. The results point out the possibility of developing a more sophisticated alloy for automotive industry.

10

Benefit Effect of Low Addition Yttrium on the Phase αMg and eutectic αMg+γ(Mg17Al12) in AZ91 Alloy

Mikusek D., Rapiejko C., Andrzejczak A., Pacyniak T.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 1

57--63

EN

This paper presents results of a study of the effect of inoculation of yttrium on the microstructure of AZ91 alloy. The concentration of the inoculant was increased in samples in the range from 0.1% up to 0.6%. The influence of Y on the thermal effects resulting from the phase transformations occurring during the crystallisation at different inoculant concentrations were examined with the use of Derivative and Thermal Analysis (DTA). The microstructures of the samples were examined with the use of an optical microscope; and an image analysis with a statistical analysis were also carried out. Those analyses aimed at examining oh the effect of inoculation of the Y on the differences between the grain diameters of phase αMg and eutectic αMg+γ(Mg17Al12) in the prepared examined material as well as the average size of each type of grain by way of measuring their perimeters.

11

Some Possibilities of Using Statistical Methods While Solving Poor Quality Production

Lakomá R., Čamek L., Lichý P., Kroupová I., Radkovský F., Obzina T.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

18--22

EN

This paper presents an overview of a research on six practical cases that were solved in a precise casting company where parts are cast by the mean of the low-wax casting method (investment casting) in order to decrease poor quality production. The steel cast parts production technology by the lost-wax method requires the detailed work procedures observation. On the base of statistical processing data of given types of casting products, it was possible to assess the significance of each particular checking events by using the statistical hypothesis testing. The attention was focused on wax and ceramic departments. The data in technological flow were compared before and after the implementation of the change and statistical confirmative influences were assessed. The target consisted in setting such control manners in order to get the right conditions for decreasing poor quality parts. It was evidenced that the cast part defect cause correct identification and interpretation is important.

12

Interaction of Titanium with Ceramic Molds in the Conditions of Electron Beam Casting Technology

Kaliuzhnyi P., Voron M., Mykhanian O., Tymoshenko A., Neima O., Iangol O.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

27--32

EN

For the manufacture of near net shape complex titanium products, it is necessary to use investment casting process. Melting of titanium is promising to carry out by electron beam casting technology, which allows for specific processing of the melt, and accordingly control the structure and properties of castings of titanium alloys. However, the casting of titanium in ceramic molds is usually accompanied by a reaction of the melt with the mold. In this regard, the aim of the work was to study the interaction of titanium melt with ceramics of shell molds in the conditions of electron beam casting technology. Ceramic molds were made by using the following refractory materials – fused corundum Al2O3, zircon ZrSiO4 and yttria-stabilized zirconium oxide ZrO2, and ethyl silicate as a binder. Melting and casting of CP titanium was performed in an electron beam foundry. Samples were made from the obtained castings and electron microscopic metallography was performed. The presence and morphology of the altered structure, on the sample surface, were evaluated and the degree and nature of their interaction were determined. It was found that the molds with face layers of zirconium oxide (Z1) and zircon (ZS1) and backup layers of corundum showed the smallest interaction with the titanium melt. Corundum interacts with titanium to form a non-continuous reaction layer with thickness of 400-500 μm. For shell molds with face and backup layers of zircon on the surface of the castings, a reaction layer with thickness of 500-600 μm is formed. In addition, zirconium-silicon eutectic was detected in these layers.

13

Influence of Mould Material on the Mechanical Properties of Wax Models

Kroma Arkadiusz, Brzęk P.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

48--52

EN

The article presents results of research on the influence of the mould material on selected mechanical properties of wax models used for production of casting in investment casting method. The main goal was to compare the strength and hardness of samples produced in various media in order to analyse the applicability of the 3D printing technology as an alternative method of producing wax injection dies. To make the wax injection dies, it was decided to use a milled steel and 3D printed inserts made using FDM (Fused Deposition Modeling) / FFF (Fused Filament Fabrication) technology from HIPS (High Impact Polystyrene) and ABS (Acrylonitrile Butadiene Styrene). A semi-automatic vertical reciprocating injection moulding machine was used to produce the wax samples made of Freeman Flakes Wax Mixture – Super Pink. During injection moulding process, the mould temperature was measured each time before and after moulding with a pyrometer. Then, the samples were subjected to a static tensile test and a hardness test. It was shown that the mould material influences the strength properties of the wax samples, but not their final hardness.

14

Effect of the Precipitation Hardening on the Structure of AlSi7Mg0.3Cu0.5 Alloy with Addition of Zr and Combination of Zr and Ti

Kuriš M., Bolibruchova D., Matejka M., Kantorikova E.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

95--100

EN

The article focused primarily on comparing the achieved mechanical results for AlSi7Mg0.3Cu0.5Zr and AlSi7Mg0.3Cu0.5Zr0.15Ti experimental alloys. Experimental variants with the addition of Zr ≥ 0.05 wt. % demonstrated the ability of Zr to precipitate in the form of Al3Zr or AlSiZr intermetallic phases. Zr precipitated in the form of long smooth needles with split ends. When evaluating the thermal analyses, the repeated peak was observed already with the initial addition of Zr in the range of approximately 630°C. It was interesting to observe the increased interaction with other intermetallic phases. EDX analysis confirmed that the individual phases are based on Cu, Mg but also Fe. Similar phenomena were observed in experimental alloys with a constant addition of Zr and a gradual increase in Ti by 0.1 wt. %. A significant change occurred in the amount of precipitated Zr phases. A more significant increase in mechanical properties after heat treatment of AlSi7Mg0.3Cu0.5Zr experimental alloys was observed mainly above the Zr content ≥ 0.15 wt. % Zr. The improvement of yield and tensile strength over the AlSi7Mg0.3Cu0.5 reference alloy after heat treatment was minimal, not exceeding 1 %. A more significant improvement after heat treatment occurred in modulus of elongation with an increase by 6 %, and in hardness with an increase by 7 %. The most significant drop occurred in ductility where a decrease by 31 % was observed compared to the reference alloy. AlSi7Mg0.3Cu0.5Zr0.15Ti experimental alloys, characterized by varying Ti content, achieved a more significant improvement. The improvement in tensile strength over the AlSi7Mg0.3Cu0.5 reference alloy after heat treatment was minimal, not exceeding 1 %. A more significant improvement after heat treatment occurred in modulus of elongation with an increase by 12 %, in hardness with an increase by 12 % and the most significant improvement occurred in yield strength with a value of 18 %. The most significant decrease also occurred in ductility where, compared to the reference alloy, the ductility drop was by up to 67 %.

15

5 Cs of Investment Casting Foundries in Rajkot Cluster – An Industrial Survey

Sata A. V., Maheta Nikunj R.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

102--108

EN

Investment casting is very well-known manufacturing process for producing relatively thin and multifarious industrial components with high dimensional tolerances as well as admirable surface finish. Investment casting process is further comprised of sub-processes including pattern making, shell making, dewaxing, shell backing, melting and pouring. These sub-processes are usually followed by heat treatment, finishing as well as testing & measurement of castings. Investment castings are employed in many industrial sectors including aerospace, automobile, bio-medical, chemical, defense, etc. Overall market size of investment castings in world is nearly 12.15 billion USD and growing at a rate of 2.8% every year. India is among the top five investment casting producer in the world, and produces nearly 4% (considering value of castings) of global market. Rajkot (home town of authors) is one of largest clusters of investment casting in India, and has nearly 175 investment casting foundries that is almost 30% of investment casting foundries of India. An industrial survey of nearly 25% of investment casting foundries of Rajkot cluster has been conducted in the year 2019-20 in order to get better insight related to 5 Cs (Capacity; Capability; Competency; Concerns; Challenges) of investment casting foundries located in the cluster. Specific set of questionnaires was design for the survey to address 5 Cs of investment casting foundries of Rajkot cluster, and their inputs were recorded during the in-person survey. The industrial survey yielded in providing better insight related to 5 Cs of foundries in Rajkot cluster. It will also help investment casting producer to identify the capabilities and quality issues as well as leads to benchmarking respective foundry.

16

Microstructure and mechanical properties of Sn-9Zn-xAl and Sn-9Zn-xCu lead-free solder alloys

Yavuzer B., Özyürek D., Tunçay T.

Materials Science Poland

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2020

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Vol. 38, No. 1

34--40

EN

This study investigates microstructures and mechanical properties of the alloys obtained by adding Cu (0.7 % and 0.9 %) and Al (0.7 % and 0.9 %) to lead-free Sn-9Zn eutectic soldering alloy produced by investment casting method. The results show that Cu5Zn8 phase has formed in the structure of Cu added alloys and the Al2O3 phase has formed due to addition of Al. It was found that small and round-shaped Al2O3 phase increased the tensile strength of the new alloy compared to the eutectic alloy. In addition, it was observed that the microhardness of Cu added alloys was lower than that of Sn-9Zn eutectic alloy, but the microhardness of alloys containing Al was higher compared to the other eutectic Sn-9Zn alloy.

17

Some Possibilities of Using Statistical Methods While Solving Poor Quality Production

Lakomá R., Čamek L., Lichý P., Kroupová I., Radkovský F., Obzina T.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 1

18--22

EN

This paper presents an overview of a research on six practical cases that were solved in a precise casting company where parts are cast by the mean of the low-wax casting method (investment casting) in order to decrease poor quality production. The steel cast parts production technology by the lost-wax method requires the detailed work procedures observation. On the base of statistical processing data of given types of casting products, it was possible to assess the significance of each particular checking events by using the statistical hypothesis testing. The attention was focused on wax and ceramic departments. The data in technological flow were compared before and after the implementation of the change and statistical confirmative influences were assessed. The target consisted in setting such control manners in order to get the right conditions for decreasing poor quality parts. It was evidenced that the cast part defect cause correct identification and interpretation is important.

18

Investigation on Reactions at Corners of Cast Part during Investment Casting of Reactive AZ91 Magnesium Alloy

Vyas Akash V., Sutaria Mayur .

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

139--144

EN

The magnesium alloy investment castings have greater potential for automobile and air-craft applications due to the higher strength to weight ratio of magnesium alloys and capability of the investment casting process to produce near net shape complex castings. The interfacial-mould metal reactions during investment casting of magnesium alloy inhibit successful production of quality castings. This paper presents the investigation done on the reactions at corners of AZ91 magnesium alloy cast part produced through investment casting. The stepped shape geometry of casting was selected to study the reactions at convex and concave corners of the cast part. The reacted surfaces were characterised using the SEM-EDX and XRD. The formation of oxides was observed on cast surface from characterisation. The temperature profile recorded at corners were helpful to understand the heat dissipation during the solidification of metal at corners. It was observed that the reactions occurred at the concave corner were more as compared to the convex corner of the cast part.

19

Selected Aspects of Manufacturing of Aluminium Sponge

Stręk A. M., Lipowska B., Wańczyk K.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

1145--1150

EN

The present article describes selected aspects of investment casting technology for manufacturing of open-cell aluminium. The main focus is, among others, on the precursor thickening. Two groups of total 30 samples were produced, basing on open-cell polyurethane foam used as the precursor. Each of the two sample groups was thickened with a different type of suspension consisting of carbonaceous substances and organic binders. The influence of the coating mixture type was compared, leading to conclusions regarding the desired composition and fluidity of the suspensions. Both sample groups of the obtained open-cell aluminium had stochastic cell distributions, the average pore diameter was 5.2 mm and the PPI index was 8. The apparent densities were respectively: 0.485 g/cm3 and 0.312 g/cm3 , which reflected the impact of the precursor coating. Additionally, samples from both groups differed in quality.

20

The Role of Recycled Ceramic Material Obtained from the Ceramic Layered Moulds Used in the Investment Casting

Soroczyński A., Haratym R., Biernacki R.

Archives of Foundry Engineering

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2019

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iss. 1

71--74

EN

The article presents the role of the ceramic layered moulds used in the investment casting method with new (certified) and recycled material from ceramic moulds (CM) after casting process. The materials that were obtained are mainly aluminosilicates and SiO2. The investigation of changes in the quality of ceramic moulds (including the recycled ceramic material) includes the chemical composition of the ceramics as recovered ceramic material, changes in the particle size of the layered covering material, the gas permeability during the pouring of liquid metal, and the creation of the porosity are presented. Than the thermophysical parameters and dimensional accuracy of the casting manufactured in the new ceramic layered shell moulds were analysed. Additionally the global cost savings and improved ecological conditions in the foundry and its surroundings was estimated.