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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

Manufacturing of Composite Castings by the Method of Fused Models Reinforced with Carbon Fibers Based on the Aluminum Matrix

Szymański Paweł

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

118--123

EN

The paper presents an attempt to produce aluminum matrix composites reinforced with short carbon fibers by precision casting in a chamber with a pressure lower than atmospheric pressure. The composite casting process was preceded by tests related to the preparation of the reinforcement. This is related to the specificity of the precision casting process, in which the mold for shaping the castings is fired at a temperature of 720°C before pouring. Before the mold burns, the reinforcement must be inside, while the carbon fiber decomposes in the atmosphere at 396°C. In the experiment, the reinforcement in the form was secured with flake graphite and quartz sand. The performed firing procedure turned out to be effective. The obtained composite castings were evaluated in terms of the degree of alloy saturation and the displacement of carbon fibers. As a result of the conducted tests, it was found that as a result of unfavorable arrangement of fibers in the CF preform, the flow of metal may be blocked and porosity may appear in the casting.

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

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.

5

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.

6

Studies of the Properties of Materials for Foundry Patterns Used in the Production of High-quality Precision Castings

Dydak A., Książek M.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 4

55--60

EN

The paper presents the properties of plastics under the trade names of PMMA and Midas, and of Formowax, Romocast 305 and Romocast 930 casting waxes. Their effect on the quality of foundry patterns used in the manufacture of ceramic moulds for precision casting is also discussed. From the selected materials for foundry patterns, samples were made for testing using the following methods: (i) 3D printing in the case of plastics, and (ii) conventional method based on tooling in the form of metal moulds (dies) in the case of casting waxes. The most important physico-mechanical properties of materials for foundry patterns were determined, i.e. linear shrinkage, softening temperature, relative elongation and coefficient of thermal linear expansion. Bending tests were carried out on samples of patterns printed and made in metal moulds, including determination of the surface roughness of patterns. After the process of melting out patterns from the cavities of ceramic moulds in an autoclave, the degree of their melting out was visually assessed (i.e. the residues from pattern removal were evaluated). The ash content after burning out of foundry patterns was also determined. The conducted tests allowed comparing the important parameters of materials used for foundry patterns and assessing the suitability of selected plastics as a material for foundry patterns used in the manufacture of high-quality precision castings.

7

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.

8

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.

9

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.

10

Wpływ ciężaru cząsteczkowego i ilości glikolu polietylenowego na właściwości mas lejnych z SiC

Wiśniewski P., Antosiewicz W., Sitek R., Mizera J.

Szkło i Ceramika

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2018

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R. 69, nr 3

11--14

PL

W artykule przedstawiono wyniki badań właściwości mas formierskich z węglika krzemu przeznaczonych do otrzymywania elementów silników lotniczych metodą odlewania precyzyjnego. Całkowite stężenie fazy stałej w ceramicznych masach lejnych z SiC wynosiło 60% wag. Spoiwem konstrukcyjnym była nanodyspersja polimerowo-ceramiczna zawierająca koloidalny Al2O3. Jako spoiwa modyfikujące zastosowano wodne roztwory glikolu polietylenowego (PGE) o ciężarach cząsteczkowych 6000, 10000 i 20000 g/mol, które dodawano w ilościach 5%, 10% i 15% wagowych w stosunku do proszku. Proszek SiC charakteryzowano pod względem: wielkości cząstek metodą dyfrakcji laserowej i za pomocą skaningowego mikroskopu elektronowego (SEM) oraz składu fazowego i chemicznego za pomocą dyfraktometrów rentgenowskich XRD i XRF. Masy formierskie charakteryzowano pod względem: lepkości dynamicznej, czasu wypływu oraz adhezji do płyty (tzw. test płyty) i grubości warstwy. Pomiary te przeprowadzano przez 96 h w warunkach laboratoryjnych w temperaturze 21ºC. Otrzymane wyniki pokazały, że masy lejne z SiC zawierające nanodyspersję oraz PGE charakteryzują się obiecującymi właściwościami i mają szansę zostać zastosowane w odlewnictwie precyzyjnym.

EN

In the present paper properties of silicon carbide slurries in manufacturing shell moulds for investment casting of aircraft turbine elements were studied. Ceramic SiC slurries with a solid concentration of 60 wt. % were applied. As a structural binder nanodispersion containing colloidal Al2O3 was used. The poly(ethylene glycol) (PGE) with molecular weight 6000, 10000 and 20000 g/mol as a rheological modificators were added at different amount: 5, 10, 15 wt. %. Characterization of SiC powder were made by: grain size by laser diffraction, Scanning Electron Microscopy (SEM) and X-Ray diffraction (XRD, XRF) methods. The properties of ceramic slurries such as: relative and dynamic viscosity, plate (plate weight test) and wax adhesion were studied by a range of techniques. These measurements were taken in laboratory conditions by 96 hours at temperature 21ºC. The results shows that SiC-based slurries, nanodispersion binder and PGE meet the investment casting requirements of aircraft turbine parts and had promising properties.

11

Structure of Precision Castings Made of the Inconel 713C Alloy

Łyczkowska K., Adamiec J.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

19--24

EN

Inconel 713C alloy belongs to the group of materials with high application potential in the aerospace industry. This nickel alloy has excellent features such as high strength, good surface stability, high creep and corrosion resistance. The paper presents the results of metallographic examinations of a base material and padding welds made by laser beam on the Inconel 713C alloy. The tests were made on precisely cast test plates imitating low - pressure turbine blades dedicated for the aerospace industry. Observations of the macro- and microstructure of the padding welds, heat-affected zone and base material indicate, that the Inconel 713C alloy should be classified as a hard-to-weld material. In the investigated joint, cracking of the material is disclosed mainly in the heat-affected zone and at the melted zone interface, where pad weld crystals formed on partially melted grains. The results show that phases rich with chromium and molybdenum were formed by high temperature during welding process, which was confirmed by EDS analysis of chemical composition.

12

Identification of Structural Components of Turbine Engine Flap After Modification of Casting Technology Parameters

Remišová A., Sládek A., Belan J.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

146--150

EN

First part of the article describes how we can by change of gating system achieve better homogeneity of product made by investment casting. Turbine engine flap was made by investment casting technology – lost wax casting. The casting process was realised in vacuum. The initial conditions (with critical occurrence of porosity) was simulated in ProCAST software. Numerical simulation can clarify during analysis of melt turbulent flow in gate system responsible for creation of entrained oxide films. After initial results and conclusions, the new gating system was created with subsequent turbulence analysis. The new design of gating system support direct flow of metal and a decrease of porosity values in observed areas was achieved. Samples taken from a casting produced with use of newly designed gating system was processed and prepared for metallography. The second part of article deals with identification of structural components in used alloy - Inconel 718. The Ni – base superalloys, which are combined unique physical and mechanical properties, are used in aircraft industry for production of aero engine most stressed parts, as are turbine blades.

13

Badania właściwości mas formierskich z korundu i glinokrzemianu przeznaczonych na ceramiczne formy odlewnicze

Wiśniewski P., Sitek R., Mizera J.

Szkło i Ceramika

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2017

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R. 68, nr 6

16--20

PL

W artykule przedstawiono wyniki badań właściwości mieszanek formierskich z korundu oraz glinokrzemianu (Remasil 60), które przeznaczono na pierwszą warstwę oraz warstwy konstrukcyjne form odlewniczych służących do odlewania precyzyjnego. Określono wpływ zawartości fazy stałej na parametry mas formierskich oraz dokonano wyboru systemów formierskich o odpowiednich parametrach. Najkorzystniejsze wyniki otrzymano dla mieszanek formierskich: przeznaczonych na warstwę przymodelową, których stężenie fazy stałej wynosiło 72,5% wag. oraz mieszanki na warstwy konstrukcyjne, gdzie udział proszku wyniósł 70% wag. Spoiwem konstrukcyjnym był nanokompozyt polimerowo-ceramiczny zawierający nanocząstki SiO2 (LUDOX AM30). Proszki charakteryzowano z użyciem: analizatora wielkości cząstek metodą dyfrakcji laserowej oraz skaningowych mikroskopów elektronowych (SEM), a nanokompozyt z wykorzystaniem mikroskopu STEM. Masy formierskie charakteryzowano pod względem: lepkości dynamicznej i względnej, gęstości, pH oraz adhezji do płyty (tzw. „test płyty”). Pomiary te przeprowadzano przez siedem dni w warunkach laboratoryjnych w temperaturze 20°C. Otrzymane wyniki pokazały, że masy lejne z korundu i glinokrzemianu oraz nanokompozytu zawierającego krzemionkę koloidalną charakteryzują się dobrymi właściwościami i mają szansę zostać zastosowane w odlewnictwie precyzyjnym do otrzymywania form.

EN

The paper presents results properties of alumina and aluminosilicate slurries dedicated to the first layer and construction layers of shell molds, respectively. The influence of the solid phase content on the parameters of the slurries was determined. Particle size distribution was determined with use of the advanced laser particle size analyzer Horiba LA-950 (LALLS technique). To characterize morphology of the powders and binder scanning electron microscopy (SEM and STEM) observations were performed. The slurries were prepared in a mechanical mixer. The experiment was based on a daily plate weight tests and pH, Zahn cup (4 mm diameter) viscosity and dynamic viscosity by rheometer with a shear rate range of 1–100–1 1/s measurements that are fundamental for investment casting industry. Adhesion of the examined mass was determined by the plate immersion (dimensions: 75×75 mm) in a slurry and estimation its weight of 75.46 g. The slurry dipping was controlled during 180 seconds with results notation every 15 seconds. The obtained results proved opportunity of their application for the investment casting and foundry, being prospective issue for future fabrication of shell moulds.

14

Badanie procesu studzenia próbek ceramicznych form odlewniczych z zastosowaniem kamery termowizyjnej

Wiśniewski P., Sitek R., Koralnik M. K., Spychalski W. L., Moszczyńska D., Mizera J.

Materiały Ceramiczne

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2017

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T. 69, nr 2

146--153

PL

W artykule przedstawiono wyniki badań materiałów formierskich, mas odlewniczych oraz procesu studzenia próbek wielowarstwowych form odlewniczych, jakie są stosowane w procesach odlewania precyzyjnego. Przygotowano mieszanki formierskie na pierwszą warstwę przymodelową i na warstwę konstrukcyjną, pokryto nimi prostopadłościenny model woskowy, uzyskując w ten sposób wielowarstwową próbkę formy odlewniczej. W ten sposób przygotowane próbki wygrzewano w piecu komorowym w temperaturze 700 °C w atmosferze powietrza w celu wytopienia wosku. Proces studzenia próbek badano z wykorzystaniem kamery termowizyjnej w zakresie temperatur 500-40 °C. Wykazano, że zastosowanie pomiarów pól temperatur za pomocą kamery termowizyjnej jest interesującym rozwiązaniem do oceny procesu studzenia form odlewniczych. Analiza procesu stygnięcia w czasie może umożliwić wykrywanie defektów form ceramicznych w postaci pęknięć, pustek czy niejednorodnej grubości, które mogą być niewidoczne gołym okiem.

EN

This paper presents investigations concerning applicability of a thermographic camera in ceramic shells cooling process. Moreover, ceramic materials and slurries have been investigated. There were slurries prepared for near-model and construction layers of a shell mould. Using the pre-prepared slurries, the ceramic near-model and construction layers were made on a wax pattern. The dewaxing process was run in a furnace at 700 °C. Cooling was investigated with the thermographic camera in the 500-40 °C temperature range. It has been proved that the usage of the thermographic camera for measurements of temperature fields was the good solution to evaluate the cooling process of ceramic shell moulds. The results showed defects like cracks, large pores or empty spaces in the ceramic shells, otherwise not visible by the unaided eye.

15

Selected Technological Properties of Liquid Ceramic Slurries Used to Produce Moulds in the Replicast cs Technology

Kaczorowski R., Just P., Pacyniak T.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 4

190--194

EN

The study discusses the issues connected with the production of thin-walled ceramic slurry in the replicast cs technology. In the ceramic mould production process, a special role is played by the liquid ceramic slurry used to produce the first layer of the mould. The study examines selected technological properties of liquid ceramic slurries used to produce moulds in the replicas cs technology. The ceramic slurries for the tests were prepared based on the binders Ludox Px30 and Sizol 030, enriched with Refracourse flour. The wettability of the pattern's surface by the liquid ceramic slurry and the dependence of the apparent viscosity on the ceramic flour content in the mixture were determined. The wettability of the pattern surface by the liquid ceramic slurry was determined based on the measurement of the wetting angle. The angle was determined by means of an analysis of the computer image obtained with the use of a CDC camera.

16

Investment casting parameters impact on IN 713C nickel-based superalloy microstructure

Roskosz S., Cygan R.

Inżynieria Materiałowa

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2016

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Vol. 37, nr 2

59--64

EN

The basic process for manufacturing of aircraft engine hot section elements made of nickel-based superalloys is investment casting using multilayer ceramic shell moulds. Introduction of new engines designs with higher thrust, lower fuel consumption and lower noise emissions enforce continual modification of casting materials, models, ceramic moulds, including melting, pouring and heat treatment processes parameters. The aim of this study was to determine the effect of pouring temperature and cobalt aluminate modifier in the subsurface layer of the mould on macrostructure of the IN 713C castings. The size of misruns, chill, columnar and equiaxed zones on the surface of the wedge castings is most affected by pouring temperature. Additionally it was proved that cobalt aluminate is an effective modifier of the IN713C superalloy causing not only refinement of equiaxed grains, but also reduction in the columnar grain size fraction.

PL

Nadstop niklu IN 713C jest stosowany między innymi na łopatki turbin silników lotniczych, odlewane precyzyjnie metodą traconego wosku w wielowarstwowych formach ceramicznych. Łopatki turbin często charakteryzują się gruboziarnistą i niejednorodną strukturą, która nie spełnia rygorystycznych wymagań dotyczących części wykorzystywanych w przemyśle lotniczym. Poprawę struktury łopatek wytworzonych z nadstopów niklu można uzyskać w wyniku odpowiedniego kształtowania wielkości ziarna w procesie odlewania. Ziarna o kontrolowanych rozmiarach można otrzymać dzięki odpowiedniej temperaturze zalewania, temperaturze formy i zastosowaniu modyfikatora w powierzchniowej warstwie formy odlewniczej. Celem badań było określenie wpływu temperatury zalewania oraz udziału modyfikatora CoAl2O4 w warstwie przypowierzchniowej formy odlewniczej na strukturę odlewów z nadstopu IN 713C.

17

Analiza stanu naprężeń własnych w odlewach łopatek turbiny z nadstopu niklu Inconel 713C

Kocurek P., Capek J., Nawrocki J., Sieniawski J.

Hutnik, Wiadomości Hutnicze

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2016

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Vol. 83, nr 5

219--222

PL

Kryteria doboru i warunki procesu technologicznego determinują stan naprężeń własnych w elementach konstrukcji maszyn i urządzeń. W pracy przedstawiono analizę oddziaływania obróbki wykończeniowej w procesie obróbki strumieniowo-ściernej na stan naprężeń własnych w warstwie wierzchniej precyzyjnych odlewów łopatek turbiny silnika lotniczego. Odlewy wytworzono z nadstopu niklu Inconel 713C metodą wytapianych modeli. Naprężenia własne w warstwie wierzchniej określono metodą dyfrakcji rentgenowskiej sin2ψ. Ustalono, że w warstwie wierzchniej łopatek występują naprężenia ściskające o wartości od -618 MPa do -719 MPa. Nie stwierdzono wpływu liczby operacji obróbki strumieniowo-ściernej na wartość naprężeń własnych w warstwie wierzchniej odlewów na głębokości do 5 μm.

EN

The selection and conditions of technological process determine the level of residual stress in structural parts. The paper presents the analysis of residual stress distribution in the surface layer of aircraft turbine blade castings after abrasive blasting process. The investigated Inconel 713C cast segment was manufactured by lost-wax casting method. The residual stresses were measured using X-ray diffraction – sin2Ψ method. In the surface layer of blades, the measured values of compressive stresses were ranging from -618 MPa to -719 MPa. Their values were not influenced by the number of abrasive blasting operations down to the depth of 5 μm.

18

Prediction of Shrinkage Porosity in Femoral Stem of Titanium Investment Casting

Sutiyoko, Suyitno, Mahardika M., Syamsudin A.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

157--162

EN

Design of gating system is an important factor in obtaining defect-free casting. One of the casting defects is a porosity caused by internal shrinkage in solidification process. Prediction of the internal shrinkage porosity in the femoral stem of commercially pure titanium (CP-Ti) is investigated based on the gating system design. The objective of this research is to get the best gating system between three gating system designs. Three gating system designs of the femoral stem were simulated in an investment casting method. The internal shrinkage porosity occurs on the largest part and near the ingate of the femoral stem. The gating system design that has ingates cross section area: 78.5; 157; and 128.5 mm2 has the least of the internal shrinkage porosity. This design has the most uniform solidification in the entire of the femoral stem. An experiment is conducted to validate the simulation data. The results of internal shrinkage porosity in the three gating system designs in the simulation were compared with the experiment. Based on the comparison, the trend of internal shrinkage porosity at the three gating system designs in the simulation agrees with the experiment. The results of this study will aid in the elimination of casting defect.

19

Enhancement of Heat Transfer in PCM by Cellular Zn-Al Structure

Naplocha K., Koniuszewska A., Lichota J., Kaczmar J. W.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 4

91--94

EN

Development of open cellular metal foam technology based on investment casting applying the polyurethane pattern is discussed. Technological process comprises preparing of the ceramic mold applying PUR foam as the pattern, firing of the mold, pouring of the liquid Zn-Al alloy into the mold and washing out of the ceramic material from cellular casting. Critical parameters such as the temperature of mold and poured metal, design of gating system affected by metalostatic pressure allowed to produce castings with cellular structure characterized by the open porosity. Metal cellular foams with the open porosity embedded in phase change material (PCM) enhance heat transfer and reduce time operations in energy storage systems. Charging and discharging were performed at the laboratory accumulator by heating and cooling with flowing water characterized by the temperatures of 97-100ºC. Temperature measurements were collected from 7 different thermocouples located in the accumulator. In relation to the tests with pure paraffin, embedding of the metal Zn-Al cellular foam in paraffin significantly decreases temperature gradients and melting time of paraffin applied as PCM characterized by the low thermal conductivity. Similarly, reduction of discharging time by this method improves the efficiency of thermal energy storage system applied in solar power plants or for the systems of energy efficient buildings.

20

Zastosowanie szybkiego prototypowania w procesie wytwarzania łopatek silników turbinowych

Nawrocki J., Rokicki P., Szeliga D., Nowotnik A., Drajewicz M., Budzik G., Sieniawski J.

Mechanik

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2015

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R. 88, nr 12CD2

143--146

PL

W ramach badań oraz wykonanych symulacji numerycznych wytworzono model zamka łopatki, który zastosowano w procesie wytwarzania form ceramicznych metodą traconego wosku. Przedstawione wyniki badań stanowią podstawę weryfikacji metody szybkiego prototypowania w procesie odlewania precyzyjnego łopatek silnika turbinowego.

EN

The research methodology and numerical simulations presented in the study were focused on execution of tip shroud blades element in meaning of further preparation of ceramic shell moulds. Obtained research results are a basis for verification of presented method in meaning of the manufacturing process.