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1

Utilizing of the Statistical Analysis for Evaluation of the Properties of Green Sand Mould

Abdulamer Dheya

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

67--73

EN

A statistical approach was conducted to investigate effect of independent factors of the mixing time compactability and bentonite percentage on dependent variables of permeability, compression and tensile strength of sand mould properties. Using statistical method save time in estimating the dependent variables that affect the moulding properties of green sand and the optimal levels of each factor that produce the desired results. The results yielded indicate that there are variations in the effects of these factors and their interactions on different properties of green sand. The outcomes obtained a range of permeability values, with the highest and lowest numbers being 125 and 84. The sand exhibited high values of tensile and compressive strength measuring at 0.33N/cm2 and 17.67N/cm2 . Conversely it demonstrated low levels of tensile and compressive strength reaching 0.14N/cm2 and 9.32N/cm2 . These results suggest that the moulding factors and their interactions have an important role in determining properties of the green sand. ANOVA was used to assess effect of various factors on different properties of the green sand. The results obtained suggest that compactability factor play a significant effect on permeability, the mixing time or bentonite factor has a significant effect on the compressive strength and mixing time or compactability factor has a significant impact on the tensile strength with a significance level lower than 5%. It is found that neither the mixing time nor the amount of bentonite used in the green sand mix has a significant impact on its permeability. Compactability of the green sand does not has a significant effect on the compressive strength. Bentonite used in green sand mix does not have a significant impact on its tensile strength.

2

Effect of Alloying Additives and Casting Parameters on the Microstructure and Mechanical Properties of Silicon Bronzes

Witasiak Dawid, Garbacz-Klempka Aldona, Papaj M., Papaj P., Piękoś Marcin, Kozana Janusz, Maj Maria, Peret-Nowak Małgorzata

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

110--117

EN

The studied silicon bronze (CuSi3Zn3Mn1) is characterised by good strength and corrosion resistance due to the alloying elements that are present in it (Si, Zn, Mn, Fe). This study analysed the casting process in green sand moulding, gravity die casting, and centrifugal casting with a horizontal axis of rotation. The influences of Ni and Zr alloying additives as well as the casting technology that was used were evaluated on the alloy’s microstructure and mechanical properties. The results of the conducted research are presented in the form of the influence of the technology (GS, GZ, GM) and the content of the introduced alloy additives on the mechanical parameters (UTS, A10, and Proof Stress, BHN). The analysis of the tests that were carried out made it possible to determine which of the studied casting technologies had the best mechanical properties. Microstructure of metal poured into metal mould was finer than that which was cast into moulding compound. Mechanical properties of castings made in moulding compound were lower than those that were cast into metal moulds. Increased nickel content affected the BHN parameter.

3

Evaluation of the Temperature Distribution of a Die Casting Mold of X38CrMoV5_1 Steel

Majernik J., Podařil M.

Archives of Foundry Engineering

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2019

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iss. 2

107--112

EN

Relatively cold die material comes into contact with the substantially higher temperature melt during the casting cycle, causing high thermal fluctuations resulting into the cyclic change of thermal field. The presented contribution is devoted to the assessment of the impact of temperature distribution on individual zones in the die volume. The evaluated parameter is the die temperature. It was monitored at two selected locations with the 1 mm, 2 mm, 5 mm, 10 mm and 20 mm spacing from the die cavity surface to the volume of cover die and ejector die. As a comparative parameter, the melt temperature in the middle of the runner above the measuring point and the melt temperature close to the die face were monitored. Overall, the temperature was monitored in 26 evaluation points. The measurement was performed using the Magmasoft simulation software. The input settings of the casting cycle in the simulation were identical to those in real operation. It was found, that the most heavily stressed die zones by temperature were within the 20 mm from the die face. Above this distance, the heat supplied by the melt passes gradually into the entire die mass without significant temperature fluctuations. To verify the impact of the die cooling on the thermal field, a tempering system was designed to ensure different heat dissipation conditions in individual locations. At the end of the contribution, the measures proposals to reduce the high change of thermal field of dies resulting from the design of the tempering channel are presented. These proposals will be experimentally verified in the following research work.

4

Investigations of the Thickness of Protective Coatings Deposited on Moulds and Cores

Jamrozowicz Ł., Kolczyk-Tylka J., Siatko A.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

131--136

EN

This article presents measurements of the thickness of alcohol-based coatings on sand foundry cores and moulds. These coatings were applied using two methods, the dipping method and the painting method. For the purposes of the study, a zircon alcohol-based coating was prepared with three different levels of nominal viscosity; very thin at 10s, average at 20s, and thick at 30s. The coating was applied to a core made of quartz sand and furan resin. The cores were made of sand with three different grain sizes; dL = 0.22 mm – fine sand, dL = 0.33 mm medium sand, and dL = 0.47 mm coarse sand. In the study, the thickness of the coating obtained to the core was measured immediately after application as well as after drying. Additionally, the extent of penetration into the intergranular spaces of the core matrix was measured. On the basis of this study, the impact of the grain size of the core matrix on the thickness of the coating and its penetration into the core was assessed. The thickness of coatings obtained using different application methods was also assessed.

5

Determination of heat accumulation coefficient for oil bonded moulding sands

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

Archives of Foundry Engineering

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2013

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Vol. 13, iss. 2

91--94

EN

The possibility of controlling the solidification and cooling time of castings creates prospects of improving their structure and by the same their properties. Thermal properties of the mould constitute therefore an important factor which is necessary to consider while seeking for the mentioned improvement. The presented work illustrates the method of determining some basic thermal coefficients of moulding material, i.e. the coefficient of temperature equalisation a2, known also as the temperature diffusivity, and the heat accumulation coefficient b2, which characterises the ability of moulding material to draw away the heat from a casting. The method consists in experimental determining the temperature field within the mould during the processes of pouring, solidification and cooling of the casting. The performed measurements allow for convenient and exact calculations of the sought-after coefficients. Examinations were performed for the oil bonded moulding sand of trade name OBB SAND ‘E’. The experiment showed that the obtained value of b2 coefficient differs from the value calculated on the basis of theoretical considerations available in publications. Therefore it can be stated that theoretical calculations of the heat accumulation coefficient are thus far not sufficient and not quite reliable, so that these calculations should be verified experimentally.

6

Charakterystyka tworzyw ceramicznych otrzymanych z udziałem zużytych mas odlewniczych ze spoiwem organicznym

Pytel Z.

Archives of Foundry Engineering

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2012

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Vol. 12, iss. 1s

153--162

PL

Referat zawiera wyniki badań tworzyw ceramicznych otrzymanych z mas plastycznych, w których składnikiem przeznaczonym do schudzania surowca ilastego były zużyte masy odlewnicze. Wprawdzie masy te pochodziły z różnych odlewni, to jednak wspólną ich cechą był rodzaj spoiwa wykorzystywanego do ich przygotowania. Spoiwa te należały do grupy spoiw organicznych, opartych na żywicach furanowych lub fenolowo-formaldehydowych. Ze względu na potencjalną możliwość emisji do atmosfery szkodliwych substancji gazowych w postaci wielopierścieniowych węglowodorów aromatycznych (WWA), mogących się uwalniać w warunkach wysokich temperatur charakterystycznych dla procesu wypalania wyrobów ceramicznych, podjęte badania stanowią próbę utylizacji jednego z najbardziej niebezpiecznych rodzajów zużytych mas odlewniczych. Koncepcja badań przewiduje otrzymanie zasadniczo dwóch rodzajów tworzyw ceramicznych. Pierwszy rodzaj stanowi tworzywo referencyjne otrzymane z masy ceramicznej, w której rolę dodatku schudzającego surowiec ilasty spełnia tradycyjny dodatek w postaci piasku kwarcowego pochodzenia naturalnego. Drugi rodzaj stanowią tworzywa eksperymentalne otrzymywane również z mas ceramicznych, lecz w tym przypadku dodatkiem schudzającym był materiał krzemionkowy otrzymany w wyniku odpowiedniego przetworzenia zużytych mas odlewniczych zawierających pozostałości spoiw organicznych, wprowadzany w ekwiwalentnej ilości w stosunku do piasku kwarcowego. Ocenę przydatności tego rodzaju surowca wtórnego we wspomnianym kierunku utylizacji, przeprowadzono w oparciu o wynik analizy porównawczej obu rodzajów tworzyw, obejmującej swym zakresem ich podstawowe cechy użytkowe oraz wybrane elementy mikrostruktury. Uzyskane wyniki badań świadczą o braku negatywnego oddziaływania na środowisko naturalne związane z potencjalną możliwością emisji WWA w trakcie produkcji tworzyw ceramicznych z udziałem zużytych mas odlewniczych zawierających pozostałości spoiw organicznych, jak również potwierdzają możliwość otrzymywania z ich udziałem tworzyw ceramicznych odznaczających się porównywalnymi właściwościami w stosunku do tworzyw referencyjnych.

EN

This study summarises the properties of ceramic materials based on plastic mixes, containing used moulding sands as the leaning agent. Though the moulding sands came from several foundry plants, they contain the same binding agent. These bonding agents belong to the group of organic binders based on furane or phenol-formaldehyd resins. In the context of potential hazards associated with hazardous gas emissions in the form of polycyclic aromatic hydrocarbons (PAHs) released at high temperatures required during the burning of ceramic products, research work is undertaken to work out the method of disposal of one of the most hazardous types of used moulding mix. Two types of ceramic materials are going to be obtained. The first type is the reference material made of the ceramic mix containing the natural silica sand as the leaning agent. The second type of ceramic products are experimental materials produced from ceramic mixes too, but in this case, the leaning agent was silica raw material obtained as a result of waste foundry moulding mixes recycling. Those waste mixes contained some residues of organic binders. The waste raw material was introduced into the final mix in amount equivalent to quartz mass in reference mix. The usability of this type of recycled product is assessed by comparative analysis of the two materials, covering their functional parameters and selected elements of microstructural analysis. Results indicate there are no negative environmental impacts associated with potential PAHs emissions during the manufacturing process of the ceramic materials containing used sand mix with organic binders and show that thus obtained ceramic materials are comparable to the reference materials in terms of their functional qualities and parameters.

7

Sieciowanie mikrofalami kompozycji poliakrylowych z udziałem dekstryny i wykorzystanie ich jako spoiw do mas odlewniczych

Grabowska B.

Polimery

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2009

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T. 54, nr 7-8

507-513

PL

Opracowano trzy kompozycje polimerowe stanowiące mieszaniny wodnych roztworów poli(kwasu akrylowego), poli(akrylanu sodu) lub soli sodowej kopolimeru kwas maleinowy-kwas akrylowy oraz dekstryny (biopolimeru). Kompozycje sieciowano za pomocą promieniowania mikrofalowego i następnie metodą FT-IR oceniano spowodowane tym procesem zmiany budowy chemicznej. Z omawianych nieusieciowanych kompozycji polimerowych użytych w charakterze spoiwa oraz piasku kwarcowego jako osnowy sporządzono masy odlewnicze, które utwardzono pod wpływem mikrofal. Zbadano wytrzymałość na ściskanie (Rcu) utwardzonych mas; największą wytrzymałość wykazują po utwardzeniu mikrofalami masy odlewnicze z udziałem kompozycji (I) poli(kwas akrylowy) + dekstryna. Metodą SEM scharakteryzowano morfologię usieciowanej masy uzyskanej z zastosowaniem kompozycji I.

EN

Three polymeric compositions being the mixtures of aqueous solutions of either poly(acrylic acid) or poly(sodium acrylate) or sodium salt of maleic acid/acrylic acid copolymer and dextrin (biopolymer) were elaborated. These compositions were crosslinked by microwave radiation and then the changes of chemical structures, caused by radiation, were evaluated by FT-IR method (Table 1-3, Fig. 1-4). Molding sands were prepared from high-silica sand as a matrix and non-crosslinked polymer compositions mentioned above as the binders. Molding sand hardening was carried out under microwave radiation. Compression strength (Rcu) of hardened molding sands was investigated (Fig. 5). The molding sands containing poly(acrylic acid) + dextrin composition (composition I) show the best compression strength. The morphology of crosslinked material prepared with use of composition I was characterized by SEM method (Fig. 6).

8

Determination of application possibilities of microwave heating in the curing process of water glass molding sands with fluid esters. Part 2

Granat K., Nowak D., Pigiel M., Stachowicz M., Wikiera R.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

51-56

EN

This article, constituting continuation of the subject discussed in the first part, presents results of the experimental trial of water glass molding sands' curing method modification with application of fluid esters and innovative microwave heating. The research objective was to determine possibilities of microwave application for curing of water glass molding sands prepared with addition of hardening agents sold under the trade name of Mach. After initial chemical curing molding sands, prepared with addition of the above mentioned hardeners, have been heated with microwaves in order to determine their influence on changes of basic technological and strength parameters of the sands, and indirectly on the quality of quartz grains binding. Studies aimed at determination of water content changes in the sands have also been undertaken. As our studies demonstrated, microwave heating allows for quick reduction of water content, thus resulting in improvement of strength parameters such as bending and tensile strength. Application of the combined methods of ester curing and innovative microwave heating facilitates production of high quality foundry moulds and cores, while simultaneously improving mould and core preparation procedures at the foundries and as a result reduces their time to an indispensable minimum.

9

Determination of application possibilities of microwave heating in the curing process of water glass molding sands with fluid esters. Part 1

Granat K., Nowak D., Pigiel M., Stachowicz M., Wikiera R.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 1

45-50

EN

This article presents results of the experimental trial of combination of the chemical method of water glass molding sands' curing, used in foundry industry, with an innovative microwave heating. The research objective was to indicate at new areas of microwave energy application. The sands prepared, according to recommendations for curing technology, with the use of ethylene glycol diacetate, have been subject to microwave influence. The attempt at determination of microwave influence on qualitative changes of the binding bridges created during the curing process concerned such parameters as: bending and tensile strength, permeability as well as wear resistance. Moreover, we also determined the influence of microwave curing on the phenomena accompanying the process as well as bond stability (storage time of the prepared molding and core sands). It has been found, basing on the result analysis, that the innovative microwave heating might constitute a very good supplementation of the ester curing method. The advantages of the combined chemical and microwave gelation process include, among others, improvement of the described resistance and technological parameters as well as significant decrease of preparation time of foundry moulds and cores. The subject discussed in this article will be continued in its second part.

10

Application of time-series analysis in foundry production

Perzyk M., Krawiec K., Kozłowski J.

Archives of Foundry Engineering

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2009

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Vol. 9, iss. 3

109-114

EN

Characterization of the time-series analysis is presented, as a data mining tool which facilitates better understanding nature of manufacturing process and permits forecasting of future values of the process parameters or production results on the basis of the past data, recorded in regular intervals. The main methods and problems of the time-series analysis are presented, related to the trend function, evaluation of seasonality and significance of the information contents in the residual values. The authors' research results, related to exemplary production data collected in a foundry with Disamatic molding line (temperature of the molding sand), are presented. It is concluded that a properly performed analysis of time-series can be a useful tool for analysis and predictions of foundry production process.

11

The influence of microwave curing time and water glass kind on the properties of molding sands

Granat K., Nowak D., Pigiel M., Stachowicz M., Wikiera R.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 4

79-82

EN

This work presents results of research on the influence of microwave heating time on the process of hardening of water glass molding sands. Essential influence of this drying process on basic properties such as: compression, bending and tensile strength as well as permeability and wear resistance, has been found. It has been proved, that all the investigated sorts of sodium water glass could be used as binding material of molding sands intended for curing with the microwave process heating. It has been found, while analyzing the results of property studies of microwave heated molding sands with 2.5% addition of water glass, that all available on the market kinds of this binding agent (including the most frequently used in foundry 145 and 149 kinds) after microwave heating guarantee very good compression, bending and tensile strength as well as permeability and wear resistance. Moreover, it has been determined that the optimal curing time of molding sands containing various kinds of water glass is 240 seconds. After this time, all basic properties of molding sands are stable. The use of microwave curing of water glass molding sands results in a significant decrease of hardening process time, full stabilization of molding sands as well as much lower energy consumption.

12

Odlewnicze masy z bentonitami- jakość a wymagania

Dobosz S. M., Asłanowicz M.

Krzepnięcie Metali i Stopów

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1998

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nr 35

83--91

PL

W artykule przeanalizowano wymagania stawiane odlewniczym masom z bentonitem pod względem jakości bentonitu, obejmujące : właściwości technologiczne mas w temperaturze otoczenia i temperaturze podwyższonej, cieplną i chemiczną deaktywację lepiszcza decydującą o trwałości mas, a także możliwość wprowadzania bentonitu do mas w postaci mieszanek z dodatkami wydzielającymi węgiel błyszczący.

EN

The article analyses the requirements, set to foundry sands with bentonite with regard to quality of bentonite, that includes: technological properties of sands in the surrounding's temperature and in the increased temperature, thermal and chemical clay's deactivation, deciding about mould's durability; and also a possibility of putting a bentonite into sands in the form of mixture with additions, that secrete a lustrous carbon.