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1

Evaluation of the Effect of External Conditions During Crystallization and Solidification on the Final Structure of AlSi7Mg

Radkovský Filip, Gawronová Martina, Kroupová Ivana

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 1

118--123

EN

Abstract The paper deals with the possibilities of influencing the final microstructure of aluminium alloy castings by changing the external conditions of crystallization and solidification. Aluminum alloys, especially Al-Si alloys, are nowadays one of the most used non-ferrous metal alloys, especially due to their mass application in the automotive field. It is in this industry that extreme emphasis is placed on the quality of cast parts with regard to safety. For this reason, a key production parameter is the mastery of the control of the resulting microstructure of the castings and the associated internal quality, which is subject to high demands defined by international standards. The aim of the experiment of this paper is to evaluate the effect of different preheating of the metal mould on the resulting structure and hardness of test castings made of AlSi7Mg0.3 material. The hardness measurement will be evaluated on a hardness tester. The parameter SDAS, Microporosity, Content of excluded eutectic will be evaluated. Dependencies will be found and plotted.

2

Effect of Chip Amount on Microstructural and Mechanical Properties of A356 Aluminum Casting Alloy

Kaya A. Y., Özaydın O., Yağcı T., Korkmaz A., Armakan E., Çulha O.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 3

19--26

EN

Aluminum casting alloys are widely used in especially automotive, aerospace, and other industrial applications due to providing desired mechanical characteristics and their high specific strength properties. Along with the increase of application areas, the importance of recycling in aluminum alloys is also increasing. The amount of energy required for producing primary ingots is about ten times the amount of energy required for the production of recycled ingots. The large energy savings achieved by using the recycled ingots results in a significant reduction in the amount of greenhouse gas released to nature compared to primary ingot production. Production can be made by adding a certain amount of recycled ingot to the primary ingot so that the desired mechanical properties remain within the boundary conditions. In this study, by using the A356 alloy and chips with five different quantities (100% primary ingots, 30% recycled ingots + 70% primary ingots, 50% recycled ingots + 50% primary ingots, 70% recycled ingots + 30% primary ingots, 100% recycled ingots), the effect on mechanical properties has been examined and the maximum amount of chips that can be used in production has been determined. T6 heat treatment was applied to the samples obtained by the gravity casting method and the mechanical properties were compared depending on the amount of chips. Besides, microstructural examinations were carried out with optical microscopy techniques. As a result, it has been observed that while producing from primary ingots, adding 30% recycled ingot to the alloy composition improves the mechanical properties of the alloy such as yield strength and tensile strength to a certain extent. However, generally a downward pattern was observed with increasing recycled ingot amount.

3

Analysis of the causes of control panel inconsistencies in the gravitational casting process by means of quality management instruments

Pacana Andrzej, Czerwińska Karolina

Production Engineering Archives

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2019

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Vol. 25

12--16

EN

All castings can have defects caused by, for example, deviations in material characteristics, structure or properties, but the skillful use of available technologies and quality management tools allows for the detection and elimination of casting incompatibilities as well as the prevention of their recurrence in the future. The aim of the article was to analyse the types of defects in castings, locate the areas with the most frequent occurrence of defects and identify the reasons for the presence of defects in castings of the control panel and its cover. The paper presents the usefulness of a combination of quality management instruments for diagnosing material discontinuities in the analyzed castings.

4

Influence of casting procedure on wear of magnesium matrix composites reinforced with carbon open-celled foam

Godzierz Marcin, Olszówka-Myalska Anita

Composites Theory and Practice

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2019

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R. 19, nr 2

64--70

EN

In this article the characteristics of the macrostructure, microstructure (LM, SEM) and selected properties of magnesium matrix composites reinforced with carbon open-celled foam with a porosity of 10 ppi, obtained by two casting techniques - gravity casting and pressure infiltration, were presented. The open porosity and hardness of the composites were determined. Tribological examinations in dry friction conditions were performed by the pin-on-disc method, and the coefficient of friction, weight loss of the sample as well as the cast iron countersample were determined, and the wear trace was characterized. Observations of the examined material surfaces after friction tests were conducted by SEM. In comparison to the gravity cast composite, a lower porosity, higher hardness and finer magnesium matrix size were found for the pressure infiltrated composite. The impact of the casting technique also concerned the tribological properties. Both the composites exhibited a lower coefficient of friction in comparison to pure magnesium, but for the pressure infiltrated composite the coefficient of friction, weight loss of the sample and countersample, as well as the depth of the wear trace were the lowest. Moreover, after the friction tests, different effects were observed on the surfaces. In the gravity cast composite the carbon component cracked and separated from the matrix, in contrast to the pressure infiltrated composite where uniform wear was observed while maintaining continuous bonding with the matrix, which explains the differences in the tribological properties.

PL

Scharakteryzowano makrostrukturę, mikrostrukturę (LM, SEM) i wybrane właściwości kompozytu na osnowie technicznie czystego magnezu zbrojonego otwartokomórkową pianą węglową o porowatości 10 ppi, otrzymanego dwiema metodami - odlewania grawitacyjnego oraz infiltracji ciśnieniowej. Określono porowatość i twardość kompozytów. Przeprowadzono badania tribologiczne w warunkach tarcia na sucho metodą pin-on-disc i wyznaczono współczynnik tarcia, ubytek masy próbki i przeciwpróbki żeliwnej oraz scharakteryzowano ślad wytarcia. Powierzchnie kompozytów po badaniach tribologicznych scharakteryzowano metodą SEM. Wykazano mniejszą porowatość, większą twardość i mniejsze ziarna osnowy magnezowej kompozytu otrzymanego metodą infiltracji ciśnieniowej w porównaniu z odlewnym grawitacyjnie. Wpływ techniki odlewania dotyczył również właściwości tribologicznych. Obydwa kompozyty charakteryzował mniejszy współczynnik tarcia w porównaniu z próbką referencyjną z materiału osnowy, ale dla kompozytu otrzymanego metodą infiltracji ciśnieniowej ten współczynnik, ubytki masy i głębokość śladu wytarcia były najmniejsze. Ponadto obserwowano różnice na powierzchni wytarcia, komponent węglowy ulegał wykruszeniu w przypadku materiału otrzymanego metodą odlewnia grawitacyjnego, a w infiltrowanym ciśnieniowo następowało jego równomierne zużycie przy zachowaniu ciągłego połączenia z osnową, co tłumaczy różne parametry tribologiczne.

5

Badanie odporności korozyjnej kratek akumulatorowych o zmiennym składzie wytwarzanych różnymi technikami

Jankowska E., Błażejczak M., Majchrzycki W., Kopciuch K., Przybyło H.

Rudy i Metale Nieżelazne Recykling

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2018

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R. 63, nr 1

3--6

PL

W artykule przedstawiono wyniki badania odporności korozyjnej kolektorów prądowych akumulatorów ołowiowych. Przebadano sześć typów kratek akumulatorowych różniących się między sobą zarówno metodą wytworzenia jak i składem. Porównano odporność korozyjną kolektorów prądowych wytworzonych metodą odlewania grawitacyjnego, punchingu oraz tzw. metodą cięto-ciągnioną. Badane kolektory prądowe zostały wykonane ze stopów o zróżnicowanym składzie, bazujących na ołowiu oraz dodatkach stopowych. Przeprowadzone badania utleniania elektrochemicznego pozwoliły zaobserwować różnice w zachowaniu kratek akumulatorowych w zależności od zastosowanego składu stopowego oraz metody wytworzenia. Dobrą odporność korozyjną, w warunkach przeprowadzonego testu w stosunku do pozostałych układów, wykazały kratki ołowiowe oznaczone jako F, wykonane techniką punching. Najwyższym średnim ubytkiem masy badanych próbek wykazały się kolektory prądowe oznaczone jako C oraz D, które wykonano techniką grawitacyjną. Nośniki masy płyt dodatnich oznaczone jako B, a wytworzone techniką cięto-ciągnioną, charakteryzowały się dobrą spójnością struktury. W przypadku próbki kratki oznaczonej jako F (punching), stwierdzono znaczne popękania w strukturze.

EN

The article describes results of corrosion tests carried out for lead-acid batteries grids. Six types of grids varying in both production technology and composition were characterized. The differences in their dimensions were noticed. The production technologies the grids were made to were: punching, expanding technology and gravity casting. The studied grids are made of alloys of different composition based on lead and alloys of additives. The electrochemical oxidation indicated some differences in behavior of grids depending on their alloy composition and production technology. The corrosion tests showed that samples marked as "F" with grids made by punching technology had a good corrosion resistance, compared to other ones. The samples marked as "C" and "D" with grids made by gravity casting method showed the highest average mass loss. The sample marked as "B" with positive plates based on grids made by expanding method was characterized as having a good structural coherence. In turn, significant cracking of the structure was noticed for the F sample (punching method).

6

Nośniki mas aktywnych akumulatorów ołowiowych VRLA do zasilania rezerwowego

Jankowska E., Kopczyk M., Baraniak M.

Rudy i Metale Nieżelazne

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2013

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R. 58, nr 5

245-253

PL

W artykule przedstawiono nośniki mas czynnych akumulatorów ołowiowych VRLA, wykonanych w technologii AGM różnych producentów. Nośniki płyt dodatnich i ujemnych badanych akumulatorów charakteryzowały się swoją indywidualną strukturę. Zauważono różnice w technologii produkcji nośników mas czynnych oraz w ich wymiarach. Do produkcji nośników płyty ujemnej zastosowano dwie technologie: ciętociągnioną i odlewanie grawitacyjne. W przypadku nośników płyt dodatnich zastosowano tylko jedną technologię wytwarzania czyli odlewanie grawitacyjne. Od dnia skonstruowania akumulatora ołowiowego przez francuskiego fizyka Gastona Planté jest on najpopularniejszym źródłem prądu stałego gromadzącym i uwalniającym energie elektryczną dzięki odwracalnym reakcjom chemicznym zachodzącym w elektrolicie. Znajduje szerokie zastosowanie w motoryzacji, jak również w innych dziedzinach przemysłu m.in. do zasilania awaryjnego i systemów zasilania rezerwowego.

EN

In the article a grids of lead-acid VRLA batteries made in AGM technology of various manufacturers have been described. Negative and positive grids of the examined batteries were characterized by their individual structure. The differences in the production technology of grids and in their dimensions were noticed. Two technologies were used for the production of negative grids: expanded technology and gravity casting. In the case of positive grids only one technology is used: the gravity casting. Since the day of constructing the lead-acid battery by Gaston Planté, this type of battery continues to be the most popular device for energy storage by means of reversible chemical reactions occurring on electrolyte/electrode interfaces. This battery widely finds application in the electromotive industry as well as for standby power systems and back-up power systems and other industries

7

Ewolucja procesu wytwarzania kratek akumulatorowych do zastosowania w rozruchowych akumulatorach ołowiowych

Kopczyk M., Majchrzycki W., Baraniak A.

Rudy i Metale Nieżelazne

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2012

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R. 57, nr 12

811-818

PL

W artykule przedstawione zostały zmiany zachodzące w przetwórstwie kratek ołowiowych do zastosowania w rozruchowych akumulatorach ołowiowych na przestrzeni ostatnich czterdziestu lat. Ukazany został rys historyczny oraz zastosowanie akumulatorów kwasowych. Omówiono budowę akumulatora i etapy jego wytwarzania. W dalszej części przedstawiono metody wytwarzania kratek ołowiowych, rozwój konstrukcji oraz ewolucję składu chemicznego stopów stosowanych do wytwarzania kratek akumulatorowych. Akumulator ołowiowy został skonstruowany w 1859 roku przez francuskiego fizyka Gastona Plante i do dzisiaj jest najbardziej popularnym źródłem energii elektrycznej otrzymywanej na drodze przemiany z energii chemicznej. Znajduje zastosowanie w samochodach, innych pojazdach, jak również do zasilania awaryjnego. Budowa akumulatora nie uległa w ciągu ostatnich kilkudziesięciu lat zasadniczym przeobrażeniom. Pojawiły się jednak nowe materiały i technologie produkcji. Zmianie uległ nie tylko skład stopu, ale również metody jego "odlewania", a co za tym idzie również konstrukcja kratki. Obecnie powszechnie stosowane są trzy technologie produkcji kratki: odlewanie grawitacyjne, odlewanie ciągłe - concast, technologia cięto-ciągniona - exmet.

EN

The article presents the changes in the lead grids manufacturing for lead?acid starter batteries during the past forty years. Next introduced methods of producing, the development of the construction and the evolution of the chemical composition of practical alloys to producing of battery grids. Lead acid battery was constructed in 1859 by Gaston Plante and to is today a most popular source of the electrical energy received on the way conversion from the chemical energy. Finds the use in cars, other vehicles, and to supplying damage. Construction of the battery in last years did not follow changes of principle. There appeared however new materials and technologies to production. The changing in grid production aren`t only the alloy composition evolution, but also they are included methods of "casting" and consequently the grid design. Currently there are three, commonly used, grid manufacturing techniques: gravity casting, continuous casting - concast, expanded technology - exmet.

8

Influence of solidification rate on microstructure of gravity cast AZ91 magnesium alloy

Barszczyńska-Malik K. N., Zyska A.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 1

23-26

EN

Derivative thermal (ATD) and microstructure analyses of gravity cast AZ91 magnesium alloy are presented. The alloy was cast into cold steel and sand moulds with the same dimensions. ATD curves - solidification curves and their first derivative - are presented. The investigated alloy exhibited a strong alloying elements segregation and the presence of [alpha] solid solution and [alpha+gamma] (Mg17Al12) eutectic mixture. Discontinuous precipitates of [gamma] phase were also observed in the microstructure of AZ91 cast into sand mould.

9

Grain refinement and heat treatment of gravity die cast A356

Lim Y. P.

Archives of Foundry Engineering

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2010

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Vol. 10, iss. 4

103--108

EN

The purpose of this investigation is to evaluate the effects of grain refiner TiCal315 (3%Ti, 0.15% C) and Al-5Ti-1B on the metallurgical properties of as-cast A356 gravity die castings as well as the improvement brought about by T6 heat treatment. The TiCal315 and Al-5Ti- 1B grain refiners were added separately into the A356 melt in different weight percentages of 0.25, 0.5, 0.75 and 1.0 to produce the gravity die casting samples. The geometry of the casting is designed to be cylindrical shape according to JIS H5202. The results show that TiCal315 is relatively more effective than Al-5Ti-1B to improve the tensile strength, hardness and elongation of A356 alloy by 10~20%. T6 heat treatment is confirmed to have more significantly improved the mechanical properties of A356 alloy compared to grain refinement. An Olympus imaging software was used to measure the average grain size of α-Al phase and the results do not show significant difference between TiCal315 and Al-5Ti-1B to grain-refine the A356 dendritic structures. The morphology of T6 heat treated A356 was changed where the irregular eutectic was converted into spherodized Si particles due to the solution treatment. This results in significant improvement in mechanical properties.

10

Electrical and tribological properties of gradient epoxy-graphite composites

Stabik J., Dybowska A.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 27, nr 1

39-42

EN

Purpose: The goal of this work was to use gravity casting as a method to prepare composite material that is characterized by gradient of electrical and tribological properties. Furthermore electrical and tribological properties of composites filled with two different kinds of graphite were compared. Design/methodology/approach: In this research the method of preparing polymeric gradient composites was gravity casting. The experimental procedure focused on evaluating the electrical resistivity and coefficient of fraction (by the pin-on-disc method) of gradient composites. Findings: Gravity casting method allowed to obtain materials with different percentage of graphite content in subsequent layers of composite. Moreover it was observed that values of coefficient of friction were higher for composite with SV94 graphite than for composite with PV60/95. Research limitations/implications: The main problem for this work was to obtain continuous change of properties depending on the distance from surface. The particle's diameter distribution, shape and size of reinforcement were significant in manufacture of composites and influenced gradient of tested properties. Practical implications: Method applied in this research allowed to obtain materials that are characterized by gradient of electrical and tribological properties. Such composites find applications in electrical industry and in mechanical engineering. Originality/value: New polymeric gradient materials were developed using gravity casting technique. Electrical and tribological properties of these composites were determined depending on distance from the surface of the test piece.

11

Improvement of quality of a gravity die casting made from aluminum bronze be application of numerical simulation

Fajkiel A., Dudek P., Walczak W., Zawadzki P.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 2

11-14

EN

The paper describes the possibility of improving the quality of gravity die cast connectors for overhead power transmission lines. The castings were made from aluminum bronze, grade CuAl9Fe1Ni1. A MAGMAsoft computer programme was used for simulation of the process of die filling and casting solidification to avoid defects, like shrinkage depression and gas porosities. The results of the simulation have finally led to redesigning of the metal feeding and cooling system and to reduced level of defects in castings.

12

Identyfikacja faz w stabilizowanym staliwie austenitycznym

Garbiak M.

Archiwum Odlewnictwa

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2006

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R. 6, nr 22

186-191

PL

W pracy przedstawiono skład fazowy i strukturę stabilizowanego dodatkami Nb i Ti staliwa żarowytrzymałego typu 0.3C-30Ni-18Cr stosowanego do wytwarzania elementów konstrukcyjnych metodą odlewania grawitacyjnego. Badania z wykorzystaniem mikroskopii optycznej oraz rentgenowskiej analizy fazowej przeprowadzono w stanie po odlaniu oraz po procesie wyżarzania - 900°C/ 300 godzin. Wykazano, że identyfikowane składniki fazowe (Ni[3]Ti, NbC, (Nb,Ti)C, TiC, M[23]C[6], G) można odróżnić na podstawie wyników pomiaru ich mikrotwardości.

EN

The paper presents results of identification of phase constituents and microstructure of creep-resistant cast steel type 0.3C-30Ni-18Cr stabilised with niobium and titanium additions and used for producing constructional elements by the gravity casting method. The alloy in as-cast and annealed condition 900°C/300 h was examined by X-ray analysis and optical microscopy to determine phase composition and microstructure respectively. It was proved that the phase constituents (Ni[3]Ti, NbC, (Nb,Ti)C, TiC, M[23]C[6], G) can be distinguished by microhardness measurements.

13

Struktura kompozytów AK7-SiC odlewanych grawitacyjnie

Mitko M., Tomczyński S.

Kompozyty

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2002

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R. 2, nr 4

220-222

PL

Przedstawiono wyniki badań struktury kompozytu metalowego typu stop aluminium zbrojony cząstkami SiC, otrzymany metodą mieszania mechanicznego i odlewania do kokil. Badania obejmują mikroskopię optyczną oraz badania rentgenowskie (dyfrakcja, mikroanaliza, struktura przełomów) i uwzględniają szczególnie strefę połączenia osnowy metalowej z cząstkami SiC. Stwierdzono bardzo silne połączenie pomiędzy cząstkami a osnową oraz wyższe stężenie Mg na granicy osnowa-cząstka SiC. Grubość strefy o wyższej zawartości Mg dochodzi do kilku mikrometrów.

EN

The work presents results of investigation concerning the structure of aluminium-silicon cast alloy matrix composite reinforced with SiC particles of dimensions 63:100 nm. The composite has been prepared by mechanical mixing of the liquid alloy and the SiC particles. The protective argon atmosphere has been maintained over the melt surface, and during the mixing process the AIMg30 master alloy (1 wt. %) has been added on the melt surface. The mixture has been gravity cast into metal molds. Optical microscopy and fracture surface examination by means of scanning microscopy have confirmed the uniform distribution of the SiC particles in the composite matrix and revealed that the metal matrix closely adheres the particles (Fig. 1a). Examination of fractures reveals the existence of strong bonding between the particles and the matrix. Cracks which frequently go across the SiC particles, and not along the matrix-SiC interface, are clear evidence of this (Fig. Ib). Diffractometry has shown that the a (Al) and B (Si) phases as well as silicon carbide (SiC) are present in the composite, i.e. the same phases as in the basic components: AK7 alloy and added particles (Fig. 2). Surface X-ray microanalysis reveals distinct boundaries between SiC particles and the matrix. The Al-rich a phase grains are clearly visible, as well as (a + B) eutectic where the Si content is higher (Fig. 3). There can be also distinguished microregions enriched with Mn, Fe and Mg, characteristic for the used east alloy (Fig. 3 and 4). Linear microanalysis performed across the SiC particle-metal matrix interface reveals the increased Mg content in the matrix layer several micrometers wide and adherent to the SiC particles (Fig. 4). The increased concentration of Mg in the bonding zone confirm the advantageous influence of applying magnesium master alloy on the melt surface during mixing the components. This allows for good wettability of particles by the liquid metal matrix and enables easy distribution of SiC particles in the liquid alloy while mixing.