Wyniki wyszukiwania - BazTech

1

Evaluation of Permeability Models for Foundry Molds and Cores in Sand Casting Processes

Sundaram Dinesh, Matsushita Taishi, Belov I., Diószegi Attila

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 1

94--106

EN

Predicting the permeability of different regions of foundry cores and molds with complex geometries will help control the regional out gassing, enabling better defect prediction in castings. In this work, foundry cores prepared with different bulk properties were characterized using X-ray microtomography, and the obtained images were analyzed to study all relevant grain and pore parameters, including but not limited to the specific surface area, specific internal volume, and tortuosity. The obtained microstructural parameters were incorporated into prevalent models used to predict the fluid flow through porous media, and their accuracy is compared with respect to experimentally measured permeability. The original Kozeny model was identified as the most suitable model to predict the permeability of sand molds. Although the model predicts permeability well, the input parameters are laborious to measure. Hence, a methodology for replacing the pore diameter and tortuosity with simple process parameters is proposed. This modified version of the original Kozeny model helps predict permeability of foundry molds and cores at different regions resulting in better defect prediction and eventual scrap reduction.

2

Evaluation of High Pressure Die Casting Mold Temperature Relations Depending on the Location of the Tempering Channels

Majernik Jan, Podaril Martin, Majernikova M.

Archives of Foundry Engineering

|

2024

|

Vol. 24, iss. 1

115--120

EN

During the casting cycle, the relatively cold material of the mold comes into contact with the significantly higher temperature melt, which causes high temperature fluctuations on the face of the mold and in its volume, which cause cyclic temperature stress. The submitted article is based on conclusions of the article “Evaluation of the temperature distribution of a die casting mold of X38CrMoV5_1 steel”, in which the modification of temperature relations of the mold in the direction from the mold face to its volume was investigated. In current article, the influence of the tempering channel distance on the temperature modification in the volume of high pressure die casting mold is investigated. Three variants of the tempering channels placements with different location respecting the mold cavity were investigated. The temperature was monitored in two selected locations, with distribution of 1mm, 2mm, 5mm, 10mm and 20mm in the direction from the mold cavity surface to the volume of fixed and movable part of the mold. As a comparative parameter, the temperature of the melt in the center of the runner above the measuring point and the temperature of the melt close to the face of the mold were monitored. The measurement was performed using Magma soft simulation software. It was discovered that up to a distance of 5mm from the face of the mold, a zone with complete heat transit without its accumulation occurs. Above this limit, the mold begins to accumulate heat, and from distance of 20mm from the face of the mold, the heat gradually passes into the entire mass of the mold without significant temperature fluctuations. The propositions derived from the results of the experiments presented at the end of the article will subsequently be experimentally verified in further research works.

3

Assessment of surface waviness of casting patterns made using 3D printing technologies

Zmarzły Paweł, Gogolewski Damian, Kozior Tomasz

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2023

|

Vol. 71, nr 1

art. no. e144585

EN

The application of 3D printers significantly improves the process of producing foundry patterns in comparison to traditional methods of their production. It should be noted that the quality of the surface texture of the foundry pattern is crucial because it affects the quality of the casting mold and eventually the finished casting. In most studies, the surface texture is examined by analyzing the 2D or 3D roughness parameters. This is a certain limitation because, in the case of 3D printing, the influence of technological parameters is more visible for irregularities of a longer range, such as surface waviness. In the paper, the influence of the 3D printing layer thickness on the formation of waviness of the surface of casting patterns was analyzed. Three 3D printers, differing in terms of printing technology and printing material, were tested: PJM (PolyJet Matrix), FDM (fused deposition modeling) and SLS (selective laser sintering). In addition, the surface waviness of patterns manufactured with traditional methods was analyzed. Surface waviness has been measured using the Form Talysurf PGI 1200 measuring system. Preliminary results of the research showed that the layer thickness significantly influences the values of waviness parameters of the surface in the casting patterns made with FDM, PJM and SLS additive technologies. The research results indicated that the smallest surface waviness as defined by parameters Wa, Wq and Wt was obtained for patterns printed using the PJM technology, while the highest was noted when using the FDM technology.

4

Negative Shrinkage of Thin-walled Investment Brass Castings

Roy Soumyajit, Pramanick A. K., Datta P. K.

Archives of Foundry Engineering

|

2023

|

Vol. 23, iss. 1

17--24

EN

Dhokra or Dokra casting is a sophisticated cast metal craft tradition of the Indian subcontinent. It has been practiced by the countryfolk now since the Copper Age. It is a lost wax casting process in the hot clay mold. The technology is such sophisticated that it can produce up to 400 μm thin-walled hollow cast products with complicated and intricate shapes using Brass, Bronze, Copper, and other copper alloys. The investigation was for engraving Brass (2% lead) which is used by Dhokra artisans nowadays. In a field visit during dimensional analysis, one discrepancy was identified. The metal thicknesses of hollow castings are thicker than the thickness of the wax pattern. This cast metal dilation phenomenon is unusual. Shrinkage of metals compared to the pattern dimension is familiar in the casting world. The same abnormalities in the repeated investigation at different sites were observed. All the studies and experiments were organized to explain the reason hidden behind the phenomenon.

5

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

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

Szkło i Ceramika

|

2018

|

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.

6

Zastosowanie technologii druku 3D do wykonania rdzenia formy odlewniczej oraz jego kontrola wymiarowa z wykorzystaniem skanera 3D

Fijołek A., Ryba J., Żak P., Lelito J.

Prace Instytutu Odlewnictwa

|

2018

|

Vol. 58, no. 2

111--124

PL

Celem pracy było opracowanie i zamodelowanie poszczególnych elementów technologii odlewniczej dla wykonywania odlewu wentylowanej tarczy hamulcowej z wykorzystaniem narzędzi CAD: program SolidWorks, a następnie wydruk rdzenia przy wykorzystaniu drukarki 3D LS ONE firmy Sand Made sp. z o.o. Następnie gotowy rdzeń został zeskanowany skanerem 3D MetraScan 70. Uzyskany w tym procesie wirtualny model został wykorzystany do kontroli wierności wykonania wydruku rdzenia w stosunku do zaprojektowanego w programie CAD obiektu. Kontrolę wymiarową zaprojektowanego modelu 3D rdzenia w stosunku do rzeczywistego obiektu przeprowadzono w oprogramowaniu Geomagic Control. Wykonana kontrola wymiarowa pozwoliła na weryfikację odchyleń wymiarowych wydrukowanego rdzenia w stosunku do jego projektu 3D wykonanego w oprogramowaniu CAD – SolidWorks. Końcowym efektem pracy był gotowy rdzeń formy odlewniczej, który po włożeniu do formy może zostać wykorzystany w procesie odlewniczym.

EN

The aim of the work was to develop and model individual elements of casting technology for the casting of a ventilated brake disc using CAD program: SolidWorks, followed by printing a core using a 3D LS ONE printer from Sand Made Ltd. Next, the finished core was scanned with the 3D MetraScan 70 scanner. The virtual model obtained in this process was used to control the fidelity of print performance in relation to the object designed in the CAD program. Dimensional control designed 3D model of the core in relation to the real object was performed in Geomagic Control software. Dimensional control made the verification of dimensional deviations printed core in relation to its project in 3D CAD software – SolidWorks. The end result was ready core for casting mold, which is inserted into the mold can be used in the foundry process.

7

Fluidity Characteristics of A201 and A206 Al-Cu Alloy

Yildirim K., Helvaci M., Gürsoy Ö., Erzi E., Kahruman C., Dispinar D.

Archives of Foundry Engineering

|

2018

|

Vol. 18, iss. 1

135--138

EN

Al-4.5Cu alloys are widely used in aerospace industries due to their low weight and high mechanical properties. This group of aluminium alloys is known as 2xx series and exhibits the highest mechanical properties however this alloy is known to suffer from feedability and high tendency for hot tearing. Al-Si alloys (3xx) have improved fluidity and better feedability particularly by several modifications such as Ti, B or Sr. Eutectic temperature is decreased and mechanical properties can be enhanced. Yet, the strength values of this alloy group cannot reach the values of 2xx series. Therefore, in this study, the effect of Ag addition on the fluidity of Al-4.5Cu alloy has been investigated. Standard size spiral mould was used. The casting temperature was selected to be 770oC. Five castings were made and Weibull statistical approach was used to evaluate the results. In addition, coating of the die with BN was also investigated. It was found that Ag addition and BN coating of the die revealed the most reproducible, reliable and high fluidity values.

8

Rozwiązania konstrukcyjne maszyn do odlewania rotacyjnego tworzyw polimerowych

Głogowska K.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

|

2017

|

T. 7, nr 2

115--118

PL

Do produkcji wielkowymiarowych wytworów takich jak zbiorniki na wodę lub olej, pojemniki na odpady, przydomowe oczyszczalnie ścieków, kajaki, separatory, bariery drogowe i inne wykorzystuje się technologię odlewania rotacyjnego. To metoda produkcyjna, która umożliwia wyprodukowanie według podanej formy odlewniczej zarówno bardzo prostych, jak i wielce złożonych wyrobów z termoplastycznych tworzyw polimerowych. Odlewanie rotacyjne jest procesem przetwórczym, w którym wykorzystuje się siłę odśrodkową działającą na odlewane tworzywo, znajdujące się w gnieździe formującym formy odlewniczej. Podczas tego procesu załadowana tworzywem forma obraca się w różnych płaszczyznach, w efekcie czego ciekłe lub uplastycznione tworzywo jest równomiernie rozprowadzone po wszystkich ściankach gniazda formującego. W zaprezentowanych artykule scharakteryzowano proces, maszyny i urządzenia do formowania rotacyjnego tworzyw polimerowych. Omówiono wady i zalety tej metody przetwórczej.

EN

The rotational moulding is most commonly used for the manufacture of seamless hollow products, the wall thickness of which may be easily adjusted by changing the ratio of rotational speed of the mould around the main and auxiliary axis. The technology of rotational moulding is used for the manufacture of large-size products of polymeric material, such as water or oil tanks, waste containers, home sewage treatment plants, kayaks, separators, sewerage wells, road barriers and other. This production method allows the manufacture, according to a given mould, of both very simple and highly complex products from thermoplastic polymeric materials. The rotational moulding is a processing process, which uses the centrifugal force influencing the material being moulded, contained in the moulding cavity of the casting mould. During this process, the mould loaded with material is rotating and as a result, the liquid or plasticized material is evenly distributed throughout all walls of the moulding cavity. The presented paper characterizes the process, machines and equipment for rotational moulding of polymeric material, and discusses the advantage and disadvantages of this processing method.

9

Technologiczne właściwości mas formierskich z SiC z przeznaczeniem dla ceramicznych form odlewniczych dla przemysłu lotniczego

Wiśniewski P., Małek M., Sitek R., Matysiak H., Kurzydłowski K. J.

Szkło i Ceramika

|

2014

|

R. 65, nr 3

11--15

PL

W artykule przedstawiono wyniki badań technologicznych 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 65% wag. Spoiwem konstrukcyjnym był nanokompozyt polimerowo-ceramiczny zawierający nanocząstki Al2O3 (IE). Jako spoiwo modyfikujące zastosowano wodny roztwór poli(alkoholu winylowego) (PVAL) 47-88 o ciężarze cząsteczkowym 47000 g/mol i stopniu hydrolizy 88%, który dodawano w ilościach 6, 10 i 15% w stosunku do proszku. Proszek SiC charakteryzowano z użyciem: wielkości cząstek metodą dyfrakcji laserowej, skaningowego mikroskopu elektronowego (SEM) oraz składu fazowego w dyfraktometrze rentgenowskim. Masy formierskie charakteryzowano pod względem: lepkości dynamicznej i względnej, gęstości, pH oraz adhezji do płyty (tzw. test płyty) oraz modelu woskowego. Pomiary te przeprowadzano przez 96 h w warunkach laboratoryjnych w temperaturze 21ºC. Otrzymane wyniki pokazały, że masy lejne w układzie SiC, nanokompozyt oraz (PVAL) charakteryzują się obiecującymi właściwościami i mają szansę zostać zastosowane do otrzymywania części silników lotniczych.

EN

In the present paper technological 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 65 wt. % were applied. As a structural binder polymer nanocomposite containing nano Al2O3 was used. The poly(vinyl alcohol) (PVAL) 47-88 with molecular weight 47000 g/mol and hydrolysis degree 88%, used as a modification binder was added at different amount: 6, 10, 15 wt. %. Characterization of SiC powder was made by: grain size by laser diffraction, Scanning Electron Microscopy (SEM) and X-Ray diffraction (XRD) methods. The properties of ceramic slurries such as: relative and dynamic viscosity, density, pH, 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 slurries based on SiC, nanocomposite binder and PVAL meet the investment casting requirements of aircraft turbine parts and had promising properties.

10

Wpływ dodatku glikolu poli(etylenowego) na właściwości mas lejnych do wytwarzania form ceramicznych na osnowie SiC do zastosowań w odlewnictwie precyzyjnym części turbin lotniczych

Małek M., Wiśniewski P., Matysiak H., Sitek R., Kurzydłowski K. J.

Przetwórstwo Tworzyw

|

2014

|

[R.] 20, nr 1 (157)

40--49

PL

W artykule przedstawiono wyniki badań właściwości technologicznych mas ceramicznych na osnowie SiC mogących znaleźć zastosowanie do produkcji form odlewniczych do odlewania precyzyjnego części turbin lotniczych. Zawiesiny ceramiczne z SiC o stężeniu 65% otrzymano w mieszadle mechanicznym z dodatkiem 6, 10, 15% wag. glikolu poli(etylenowego) spełniającego rolę spoiwa oraz upłynniacza. Przeprowadzono szereg badań materiałoznawczych dla proszku, polimeru oraz wytworzonych mas lejnych, w tym lepkość względną i dynamiczną, pomiar gęstości, pH oraz zanurzeniowy test płyty mosiężnej. Pomiary prowadzono przez 96 h.

EN

The presented paper relate the application of SiC in manufacturing shell moulds for investment casting of aircraft turbine elements. The tested shell moulds were produced through the „dip and stucco” method. Ceramic slurries with a SiC concentration of 65% wt. were applied. The polyethylene glycol was added at different ranges (6, 10, 15% wt.) as a binder and a flow agent. The characterization of SiC powder was done by Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD) methods. Properties of ceramic slurries such as: relative and dynamic viscosity, density, pH and plate weight were studied using a range of techniques. The results shows that slurries based on SiC and polyethylene glycol meet the investment casting requirements of aircraft turbine parts and have very promising properties.

11

Technological Properties of SiC-Based Ceramic Slurries for Manufacturing Investment Casting Shell Moulds

Małek M., Wiśniewski P., Matysiak H., Zagórska M., Kurzydłowski K.J.

Archives of Metallurgy and Materials

|

2014

|

Vol. 59, iss. 3

1059--1062

EN

In this work technological properties of ceramic slurries based on silicon carbide were characterized. Silicon carbide and poly(vinyl alcohol) in an amount 6%, 10% and 15 wt. % as a solution were added to prepare the ceramic slurries. Solid phase content in ceramic slurries was 62,5 wt.%. Plate weight test, pH, density, viscosity (measured by the Zhan 4# cup) and dynamic viscosity were investigated. Dipping test on wax model was done to measure adhesive properties. Characterization of SiC fillers powder was made by determination of grain size, density, chemical composition, Zeta potential and by use of scanning electron microscopy. Obtained results of ceramic slurries based on SiC meet standard specification in industrial investment casting and its properties are very promising for future application in investment casting of superalloys.

PL

W artykule przedstawiono wyniki badań właściwości technologicznych mas ceramicznych na osnowie SiC mogących znaleźć zastosowanie do produkcji form odlewniczych do odlewania precyzyjnego części turbin lotniczych. Zawiesiny ceramiczne z SiC o stężeniu 62,5% otrzymano w mieszadle mechanicznym z dodatkiem 6, 10, 15% wag. alkoholu poli(winylowego) spełniającego rolę spoiwa oraz upłynniacza. Przeprowadzono szereg badań materiałoznawczych dla proszku, polimeru oraz wytworzonych mas lejnych, w tym lepkość względną i dynamiczną, pomiar gęstości, pH oraz zanurzeniowy test płyty. Pomiary prowadzono przez 96h. Udowodniono, iż właściwości technologiczne oraz reologiczne ceramicznych mas pozwalają na zastosowanie ich do produkcji form odlewniczych przeznaczonych do procesów odlewania precyzyjnego części turbin lotniczych.

12

The Influence of the Mould Filling Conditions on the Quality of Castings Made of EN AC-44000 Alloy

Nadolski M., Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

|

2014

|

Vol. 14, iss. 2

19--22

EN

The work deals with the influence of change in the filling conditions of the ceramic moulds with plaster binder on the presence of gaseous porosity and the microstructure of the achieved test castings with graded wall thickness. Castings made of EN AC-44000 alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal technology), or by counter-gravity casting were compared. The results of examinations concerning the density of the produced castings indicate that no significant change in porosity was found. The increased size of silicon crystals was found for the increased wall thicknesses due to the slower cooling and solidification of castings.

13

The Influence of the Method of Mould Filling on the Quality of Castings Made of EN AC-44000 or EN AC-46200 Alloy

Nadolski M., Konopka Z., Łągiewka M., Zyska A.

Archives of Foundry Engineering

|

2014

|

Vol. 14, iss. 4

73--76

EN

The performed examinations concerning the process of filling the plaster ceramic moulds with aluminium alloys allowed to assess the influence of various methods of introducing the metal into the mould cavity on the macro- and microstructure of the obtained experimental castings. The comparison was performed for castings with graded wall thickness made either of EN AC-44000 alloy or of EN AC-46000 alloy, produced either by gravity casting, or by gravity casting with negative pressure generated around the mould (according to the Vacumetal technology), or by counter-gravity casting. It was found that the silicon crystals grow in size with an increase in wall thickness due to the slower cooling and solidification of castings.

14

Application of a New Innovative Ceramic Material for Investment Casting Technology

Stefański Z., Izdebska-Szanda I., Angrecki M.

Archives of Foundry Engineering

|

2014

|

Vol. 14, iss. 1 spec.

51--56

EN

The article presents the research results of a new ceramic material, in which olivine sand was used as the matrix. This new ceramic material was studied at the angle of its application in the investment casting technology. This material will be mainly used for preparing self-supporting moulds for castings made of aluminium and magnesium alloys, replacing the expensive material – molochite which has been used so far. The article presents the results of mineralogical research of olivine sand, as well as thermophysical research of the new ceramic material made on the olivine sand matrix. Comparative research of both materials was conducted, i.e. with the olivine and molochite matrix, then the assessment of the quality of the new ceramic material was made. What is more, the research results of the developed ceramics and its usefulness for the production of castings are presented.

15

Heat exchange in the system mould–riser–ambient. Part I: Heat exchange coefficient from mould external surface

Krajewski P. K., Zovko-Brodarac Z, Krajewski W. K.

Archives of Metallurgy and Materials

|

2013

|

Vol. 58, iss. 3

833--835

EN

The subject of the paper is heat exchange in the system casting - riser - ambient. The examinations were focused on evaluating temperature dependence of the coefficient of heat exchange from mould external surface (or from riser thermally insulated surface) to ambient. The examinations were carried out for the surface temperatures of 200-800°. On the basis of the performed examinations it was stated that the relationship αext:eff vs. surface temperature can be described by a polynomial of 3rd degree with accuracy of 90-95% and that the αext:eff coefficient significantly depends on the examined material mass density.

PL

Praca dotyczy określenia temperaturowej zależności współczynników, opisujących intensywność wymiany ciepła w układzie odlew - nadlew - forma odlewnicza - otoczenie. Na podstawie pomiarów temperatury i bilansów cieplnych określono wartości sumarycznego współczynnika wymiany ciepła do otoczenia z powierzchni nagrzanej warstwy ochronnej (izolacyjnej) górnej powierzchni nadlewu, w zakresie temperatury 200-800°. Uzyskano zależności o stosunkowo dobrym dopasowaniu, na poziomie R2 (0.9-0.95). Porównawcza analiza wyników dla dwóch zbadanych materiałów, różniących się gęstością masy i pojemnością cieplną, wykazała, iż nie ma prostej zależności pomiędzy nimi, to jest wartość sumarycznego współczynnika wymiany ciepła nie zmienia się wprost proporcjonalnie do iloczynu gęstości masy i pojemności cieplnej. Uzyskane wyniki mogą być wykorzystane do określenia warunków początkowo-brzegowych w konstruowanych modelach numerycznych wymiany ciepła w układach odlew - nadlew - forma odlewnicza - otoczenie.

16

Shaping the Structure and Properties of High Quality Silumin Castings in Metal Molds Cooled with Water Mist

Władysiak R.

Archives of Foundry Engineering

|

2013

|

Vol. 13, iss. 2 spec.

98--105

EN

The paper presents some aspects of the theory and technology of high quality silumin castings in metal molds cooled pointed with water mist stream. The results of the work relate to improvement of the properties of silumin casts by affecting the cooling of the liquid silumin in gravity cast in metal mold and the possibility of controlling the solidification and crystallization of the casting. The high efficiency required from the cooling system is a consequence of an optimal selection of parameters of the generated mist and the maximum use of the phenomenon of water droplets evaporation on the surface of the cooled mold. The study showed that sequential spot cooling with use of water mist, characterized by a wide range of control means and a high maximum heat transfer efficiency, enables to control the flow of heat between the casting and the mold and it allows for a layered solidification leading to the realization of the entire cast solidification in the expected way: directional or simultaneous. Consequently, the results are: improvement of the quality of the castings as a result of the elimination of defects and significant reduction in shrinkage porosity in the casting, an increase of the homogeneity and fineness of the microstructure, about 25% increase in the mechanical properties.

17

Wybuch pary wodnej w formie odlewniczej

Wróbel I, Mirota K

Mechanik

|

2012

|

R. 85, nr 7CD

1003--1010

PL

W referacie opisano zjawisko wybuchu pary wodnej, który jest wynikiem awarii systemu chłodzenia formy. Zbudowano odpowiedni model dyskretny elementów formy, który posłużył do badania ich wytrzymałości. Sformułowano wnioski.

EN

Effect of steam explosion, which is the result of the mold cooling system failure was described in the paper. The FEM form model was built that was used to test their strength. The conclusions have been formulated

18

The methods of calculating the solidifying strand shell thickness in a continuous casting machine

Miłkowska-Piszczek K., Dziarmagowski M., Buczek A., Pióro J.

Archives of Materials Science and Engineering

|

2012

|

Vol. 57, nr 2

75--79

EN

Purpose: The steel solidifying process during continuous casting starts in the mould, where between 15 and 30% of total heat is abstracted. The strand withdrawn from the mould should have a solidified shell to ensure a failure free operation of the continuous caster. For a steel continuous casting process, it is necessary to obtain the correct shell thickness of the strand forming in the mould. If the shell thickness is insufficient, it will break out and the liquid core will leak, causing pouring of one or more segments of the machine. The presented paper shows the results of calculations of the shell thickness of the strand withdrawn, made with various mathematical models and the ProCAST software. Design/methodology/approach: Three mathematical models with various degree of complexity with a complex numerical model were compared. Similar values of the strand shell thickness were have been received, and small differences result from the degree of complexity of the applied calculation models. Findings: Similar findings related to the shell thickness were obtained. However, the use of more complex models is more likely to give correct and more accurate results. Practical implications: For a failure-free steel continuous casting process, it is necessary to obtain the correct shell thickness of the strand forming in the continuous caster mould. Originality/value: The presented paper compares the values of strand shell thickness obtained on the basis of mathematical models with various degree of complexity with a complex numerical model of the continuous casting process. Similar findings were obtained.

19

The influence of material of mould and modification on the structure of AlSi11 alloy

Łągiewka M., Konopka Z.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 1

67-70

EN

The presented work discusses the influence of material of foundry mould on the effect of modification of AlSi11 alloy. For this purpose castings were produced in moulds made of four various materials. Castings of the first type were cast in a metal die, the second ones in the conventional mould of bentonite-bound sand, those of the third type in the sand mould with oil binder, the last ones in a shell mould where phenol-formaldehyde resin was applied as a binder. All the castings were made of AlSi11 alloy modified with strontium. For a purpose of comparison also castings made of the non-modified alloy were produced. The castings were examined with regard to their microstructures. The performed investigations point out that the addition of strontium master alloy results in refining of the alloy structure, particularly of the \alfa-phase, causes some morphological changes in the alloy and the refinement of eutectics. The advantageous influence of modifier on the structure of the examined silumin was observed particularly in the case of alloy cast either in the conventional oil-bound sand mould or in the shell mould. The non-modified alloy cast into a metal die exhibits a structure similar to those of modified alloy solidifying in the other moulds. The improvement in both tensile strength and unit elongation suggests that the modification was carried out correctly. The best mechanical properties were found for the alloy cast in a metal die, both with and without modification treatment.

20

Production of castings by patternless process

Pastirčák R., Urgela D., Krivoš E.

Archives of Foundry Engineering

|

2012

|

Vol. 12, iss. 1

87-92

EN

This paper deals with production of safety inlay for steam locomotive valve by the Patternless Process method. For the moulds creation was used moulding mixtures of II. generation, whereas binder was used a water glass. CNC miller was used for creation of mould cavity. Core was created also by milling into block made of moulding compound. In this article will be presented also making of 3D model, setting of milling tool paths and parameters for milling.