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Modern Foundry Materials and Technologies

A special issue of Materials (ISSN 1996-1944). This special issue belongs to the section "Metals and Alloys".

Deadline for manuscript submissions: closed (10 August 2023) | Viewed by 24251

Special Issue Editors

Department of Material Science, Faculty of Mechanical Engineering, Technical University of Liberec, Studenstká 2, 461 17 Liberec, Czech Republic
Interests: new casting materials and technologies; nanomaterials and nanotechnologies; creation and evaluation of thin layers properties
Special Issues, Collections and Topics in MDPI journals
Department of Foundry Engineering, Faculty of Mechanical Engineering, Silesian University of Technology, 7 Towarowa Street, 44-100 Gliwice, Poland
Interests: cast iron; intermetallic phases; crystallization process; electromagnetic stirring; quality of castings; corrosion of metal alloys; lost wax method; continuous castings; 3d printing process; reverse engineering
Special Issues, Collections and Topics in MDPI journals
Department of Materials Engineering and Production Systems, Faculty of Mechanical Engineering, Lodz University of Technology, 90-924 Lodz, Poland
Interests: cast iron; crystallization; heat treatment; quality of castings; non-ferrous alloys; ausferrite; casting technology

Special Issue Information

Dear Colleagues,

The global increase in the number of castings produced has resulted in a growing demand for the latest specialist knowledge in the field of the foundry. The structure of cast elements is subject to dynamic changes—e.g., to reduce their weight and improve performance parameters (strength, hardness, resistance to abrasive wear, corrosion resistance).

This is why we are looking for new solutions in the field of casting technology that will optimize the casting production process itself, reduce production costs, and ensure appropriate quality. An important element in this is the appropriate selection of casting alloys.

However, this progress is conditioned by the high quality of research and publications, which will allow the implementation of new solutions and materials to ensure their high competitiveness in a dynamically changing market. Many important aspects of foundry theory and practice are still the subject of lively debate among scientists.

For example, in recent times there have been many conflicting opinions in the scientific community about the inclusion of nonmetallic material in castings. In particular, the phenomena accompanying the production of bifilms and their impact on the quality parameters of castings are an issue that arouses conflicting opinions in the foundry environment. An attempt to explain the complicated phenomena accompanying the use of bifilms in casting would be a valuable contribution to this Special Issue.

This Special Issue aims to cover all foundry technologies and alloys (cast steel, cast iron, and nonferrous alloys). Due to the topics covered in this Special Issue, articles on the use of modern solutions in the technology of casting production are welcome. Topics covered may include the optimization of foundry production, methods of metal preparation, crystallization, the electromagnetic mixing of foundry alloys, and quality control.

We invite you to submit original research papers or review articles that describe the current state-of-the-art within the scope of this Special Issue on ‘Modern foundry materials and technologies’.

Prof. Dr. Petr Louda
Prof. Dr. Marcin Stawarz
Prof. Dr. Grzegorz Gumienny
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Materials is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • cast iron
  • crystallization
  • intermetallic phases
  • corrosion of metal alloys
  • modern castings technologies
  • bifims
  • casting alloys
  • abrasive wear
  • electromagnetic mixing
  • production processes

Published Papers (14 papers)

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Research

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16 pages, 6726 KiB  
Article
Determination of Saturation Conditions of the Aluminum Metal Matrix Composites Reinforced with Al2O3 Sinter
by Paweł Szymański, Paweł Popielarski, Dorota Czarnecka-Komorowska, Robert Sika and Katarzyna Gawdzińska
Materials 2023, 16(18), 6106; https://doi.org/10.3390/ma16186106 - 07 Sep 2023
Viewed by 819
Abstract
Aluminum metal matrix composites (Al MMCs) are a class of materials characterized by being light in weight and high hardness. Due to these properties, Al MMCs have various applications in the automobile, aeronautical and marine industries. Ceramic-reinforced Al MMCs in the form of [...] Read more.
Aluminum metal matrix composites (Al MMCs) are a class of materials characterized by being light in weight and high hardness. Due to these properties, Al MMCs have various applications in the automobile, aeronautical and marine industries. Ceramic-reinforced Al MMCs in the form of sinters are known for having excellent abrasive properties, which makes them an attractive material in certain fields of technology. The biggest problem in their production process is their low ability to infiltrate ceramics with alloys and consequently the difficulty of filling a ceramic preform. The castability of such composites has not yet been researched in detail. The aim of this study was to create aluminum metal matrix composite castings based on aluminum alloys (AlSi11) reinforced with an Al2O3 sinter preform using a Castability Trials spiral mold, and then to determine the degree of saturation with the liquid metal of the produced ceramic shaped body (Castability Trials spiral). For the selected AlSi11 alloy, the liquidus (Tl) and solidus (Ts) temperatures were determined by performing thermal-derivation analysis during cooling, which is Tl—579.3 °C and Ts—573.9 °C. The resultant pressure necessary for the infiltration process was estimated for the reinforcement capillaries with the following dimensions: 10, 15, 20, 25, 30 and 35 microns. The following values were used to determine the capillary pressure (Pk): surface tension of the alloy—σ = 840 mN/m; the extreme wetting angle of the reinforcement by the metal—θ = 136°. It has been experimentally confirmed that for the vacuum saturation process, the estimated resultant pressure enables saturation of reinforcement with capillaries larger than 25 microns, provided that the alloy temperature does not drop lower than the infiltration temperature. After the experiment, the time and route of the liquid metal flow in the spiral were determined. On the basis of the obtained values, a simulation was developed and initial assumptions such as saturation time, alloy temperature, reinforcement and mold temperature were verified. The energy balance showed that the saturation limit temperature was Tk = 580.7 °C for the reinforcement temperature of 575 °C. In contrast to the above, the assumption that the temperature of the metal after equalizing the temperature of the composite components must be higher than the liquidus temperature (Tliq = 579.3 °C) for the aluminum alloy used must be fulfilled. After the experiment, the time and path of the liquid metal flow in the spiral were determined. Then, on the basis of the obtained values, a simulation was developed, and the initial assumptions (saturation time and temperature) were verified. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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14 pages, 4280 KiB  
Article
Refinement of the Magnesium–Aluminium Alloy Microstructure with Zirconium
by Cezary Rapiejko, Dominik Mikusek, Bartłomiej Januszewicz, Krzysztof J. Kubiak and Tadeusz Pacyniak
Materials 2022, 15(24), 8982; https://doi.org/10.3390/ma15248982 - 15 Dec 2022
Viewed by 1075
Abstract
The magnesium–aluminium alloy AZ91 was inoculated with zirconium to refine the microstructure. Six different concentrations of zirconium content were tested, ranging from 0.1 to 0.6 wt %, and compared to the baseline AZ91 alloy without modification. Melted metal was poured into a preheated [...] Read more.
The magnesium–aluminium alloy AZ91 was inoculated with zirconium to refine the microstructure. Six different concentrations of zirconium content were tested, ranging from 0.1 to 0.6 wt %, and compared to the baseline AZ91 alloy without modification. Melted metal was poured into a preheated ceramic mould and the temperature was measured and recorded during the solidification. The derivative and thermal analysis (DTA) was performed to compare the crystallisation dynamics. Formed microstructure was analysed using an optical microscope, scanning electron microscopy (SEM-EDX) and energy dispersive X-ray spectrometry (XRD). The chemical composition was measured using an arc spectrometer. The time of solidification was shortened for the samples with a concentration of zirconium 0.3 wt % and the microstructure was refined. The level of grain refinement remained below 10% and the grain shape was changed to more spherical shapes. Both the primary magnesium and eutectic phases were modified. However, at a low concentration of zirconium (0.1 and 0.2 wt %), the primary grain size was increased. Therefore, the optimal zirconium concentration was 0.3 wt %. Larger concentrations (0.4 to 0.6 wt %) did not provide any additional benefit. Theoretical analysis showed that some Al3Zr intermetallic phases can form, which was confirmed on the derivate curve of the thermal analysis, and SEM-EDS and XRD analyses. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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13 pages, 5328 KiB  
Article
Effect of Degassing Parameters on Mechanical Properties of EN AC-46000 Gravity Die Castings
by Grzegorz Gumienny, Bogusław Pisarek, Tomasz Szymczak, Jakub Gawroński, Paweł Just, Ryszard Władysiak, Cezary Rapiejko and Tadeusz Pacyniak
Materials 2022, 15(23), 8323; https://doi.org/10.3390/ma15238323 - 23 Nov 2022
Viewed by 2192
Abstract
The article is devoted to the optimization of the degassing parameters of the AlSi9Cu3(Fe) alloy. The alloy was degassed with a solid degasser (Ecosal) and nitrogen or argon. The variable parameters were time and type of degasser. The test castings were made in [...] Read more.
The article is devoted to the optimization of the degassing parameters of the AlSi9Cu3(Fe) alloy. The alloy was degassed with a solid degasser (Ecosal) and nitrogen or argon. The variable parameters were time and type of degasser. The test castings were made in permanent molds with an internal diameter of 25 mm and a length of 150 mm. The effect of the degassing time and the amount of degasser on the mechanical properties, as well as the hydrogen content and density index were investigated. The ALU SPEED TESTER developed by FMA was used to test the hydrogen content and the density index. Magmasoft software was used to design the geometry of the test castings. A significant effect of the solid degasser and degassing time on both the density index and the hydrogen content was demonstrated. Replacing nitrogen with argon did not bring any significant improvement in the above-mentioned parameters. The effect of degassing parameters on the mechanical properties of the EN AC-46000 alloy was much less significant, but was still visible. The optimal degassing parameters needed to obtain the highest strength parameters of the EN AC-46000 gravity die castings were determined. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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14 pages, 5343 KiB  
Article
Graphite Nodularity Evaluation in High-Si Ductile Cast Irons
by Iulian Riposan, Denisa Anca, Iuliana Stan, Mihai Chisamera and Stelian Stan
Materials 2022, 15(21), 7685; https://doi.org/10.3390/ma15217685 - 01 Nov 2022
Cited by 6 | Viewed by 1539
Abstract
Ferritic high-Si ductile cast irons replace an unstable mixed ferrite-pearlite matrix with a unique combination of high elongation, strength and hardness (ideal for automotive drive train components) and resistance to oxidation and corrosion at high temperatures (automotive exhaust and turbocharger systems). The present [...] Read more.
Ferritic high-Si ductile cast irons replace an unstable mixed ferrite-pearlite matrix with a unique combination of high elongation, strength and hardness (ideal for automotive drive train components) and resistance to oxidation and corrosion at high temperatures (automotive exhaust and turbocharger systems). The present paper analyses the graphite parameters of 4.5%Si, un-inoculated ductile cast iron (4.7%CE, 0.035%Mgres) as an effect of the casting section size. The structure is characterized by 10.5–11.2% graphite and 464–975 nodules/mm2, at more than 70% ferrite and no carbides, including at 3 mm wall thickness. The lower the wall thickness is, the higher the nodule count is and, consequently, the higher the ferrite amount is. The Roundness Graphite Shape Factor (RSF = 0.65–0.68) illustrates the presence of Slightly Irregular Spheroidal Graphite (Form V ISO 945). There is a big difference between the graphite nodularity evaluated according to ISO 16112:2017 [CGI] (NG1 = 79–86%) and according to ISO 945-4-2019 (DI) (NG2 = 65.2–74.6%), both of them based on RSF. Graphite Nodularity (NG3), calculated with the ISO 945-4-2019 [DI] formula, but replacing RSF with SSF, Sphericity Graphite Shape Factor, has an intermediary position. The higher the imposed minimum RSF or SSF is, the lower the Graphite Nodularity (NG4, NG5): 80–90% for min. 0.50 (minimum Form IV or Intermediate Graphite), 60–80% for min. 0.60–0.65 (minimum Form V graphite) and 35–70% for min. 0.80 (minimum Form VI graphite). The SSF is more representative than the RSF for Si-alloyed ductile cast iron, so it is recommended to use a graphite nodularity calculus considering SSF instead of the RSF formula (stipulated by ISO 945-4-2019), with SSF replacing RSF. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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23 pages, 23541 KiB  
Article
Grain Refiner Settling and Its Effect on the Melt Quality of Aluminum Casting Alloys
by Gábor Gyarmati, Levente Bogoly, Marcin Stawarz, György Fegyverneki, Zoltán Kéri, Monika Tokár and Tamás Mende
Materials 2022, 15(21), 7679; https://doi.org/10.3390/ma15217679 - 01 Nov 2022
Cited by 1 | Viewed by 1632
Abstract
Grain refiner particles, which are intended to induce the formation of fine equiaxed grain structure during the solidification of aluminum alloys, are prone to settling during the holding of the liquid metal, which phenomenon can affect not only the grain size but the [...] Read more.
Grain refiner particles, which are intended to induce the formation of fine equiaxed grain structure during the solidification of aluminum alloys, are prone to settling during the holding of the liquid metal, which phenomenon can affect not only the grain size but the spatial distribution of the double oxide films in the melt. In this study, the settling of Al3Ti inoculant particles, as well as its effects on melt quality and grain refinement, were studied. During the experiments, the Ti-concentration of a liquid Al-Si-Mg-Cu alloy was increased to 0.3 wt.% by the addition of Al-10%Ti master alloy at different melt temperatures. Particle settling and grain size evolution were studied by quantitative metallography, while the interactions of grain refiners and bifilms were investigated by scanning electron microscopy (SEM). The evolution of melt quality was assessed by the computed tomographic (CT) analysis of reduced pressure test (RPT) samples. It was found that effective grain refinement was only realized when the introduced blocky Al3Ti particles were dissolved and re-precipitated in the form of (Al,Si)3Ti at a lower temperature. Without dissolving at higher holding temperatures, Al3Ti particle settling has taken place within 10 min. The settling of (Al,Si)3Ti particles improved melt quality by the aided sedimentation of bifilms in the melt. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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25 pages, 12978 KiB  
Article
Heat Transfer Analysis of 3D Printed Wax Injection Mold Used in Investment Casting
by Bartłomiej Burlaga, Arkadiusz Kroma, Przemysław Poszwa, Robert Kłosowiak, Paweł Popielarski and Tomasz Stręk
Materials 2022, 15(19), 6545; https://doi.org/10.3390/ma15196545 - 21 Sep 2022
Cited by 5 | Viewed by 2169
Abstract
Investment casting is one of the precise casting methods where disposable wax patterns made in wax injection molds are used to make a casting mold. The production capacity of precision foundry is determined by the time taken for producing wax patterns, which depends [...] Read more.
Investment casting is one of the precise casting methods where disposable wax patterns made in wax injection molds are used to make a casting mold. The production capacity of precision foundry is determined by the time taken for producing wax patterns, which depends on the time taken for wax solidification. Wax injection molds are usually made of aluminum or copper alloys with the use of expensive and time-consuming computer numerical control (CNC) processing, which makes low-volume production unprofitable. To reduce these costs, the authors present a heat transfer analysis of a 3D printed wax injection mold. Due to the low thermal conductivity of the photopolymer resin, the influence of different cooling channels’ shapes was investigated to improve the time of the manufacturing process. Transient thermal analysis was performed using COMSOL software based on the finite element method (FEM) and included a simulation of wax injection mold cooling with cold air (−23 °C), water, and without cooling. The analysis showed that use of cooling channels in the case of photopolymer material significantly reduces the solidification time of the sample (about 10 s shorter), and that under certain conditions, it is possible to obtain better cooling than obtained with the aluminum reference wax injection mold (after approximately 25–30 s). This approach allows to reduce the production costs of low-volume castings. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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12 pages, 4378 KiB  
Article
Effect of the Type of Inorganic Binder on the Microstructure and Properties of AlSi7Mg Alloy Castings Made by Ablation Casting Technology
by Jadwiga Kamińska, Michał Angrecki and Sabina Puzio
Materials 2022, 15(14), 4912; https://doi.org/10.3390/ma15144912 - 14 Jul 2022
Viewed by 1470
Abstract
The results of studies on the effect that the type of binder and casting technology exert on the microstructure and properties of AlSi7Mg alloy castings are discussed in this paper. Comparative tests were carried out on three casting manufacturing technologies, i.e., conventional sand [...] Read more.
The results of studies on the effect that the type of binder and casting technology exert on the microstructure and properties of AlSi7Mg alloy castings are discussed in this paper. Comparative tests were carried out on three casting manufacturing technologies, i.e., conventional sand mould casting and cooling process, metal mould (die) casting, and sand mould casting with ablation breakdown of mould and cooling of castings. Moulds were made from four different sand mixtures with inorganic binders hardened by various technologies. The microstructure of test castings was examined at three different levels, i.e., in the upper part, central part, and lower part of each casting. The tensile test at room temperature was carried out in accordance with standards. The experimental results showed differences in the microstructure of castings. The differences resulted from changes in the crystallisation path due to the use of three different casting technologies, ensuring different rates of heat dissipation from castings; they were also due to the shape of castings. It has been shown that castings made by ablation technology are characterised by a high degree of the microstructure refinement (SDAS reduced by 18–30%), which gives higher strength properties than the properties of castings made in conventional sand moulds. Samples taken from castings made by the ablation technology in moulds with phosphate binder and microwave-hardened geopolymer binder were characterised by the mechanical properties comparable to gravity die castings. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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16 pages, 8679 KiB  
Article
Selected Properties of a Zr-Containing AlSi5Cu2Mg Alloy Intended for Cylinder Head Castings
by Dana Bolibruchová, Lukáš Širanec and Marek Matejka
Materials 2022, 15(14), 4798; https://doi.org/10.3390/ma15144798 - 08 Jul 2022
Cited by 4 | Viewed by 1262
Abstract
The aim of this paper was to analyze the impact of the addition of different amounts of zirconium (0.05; 0.10; 0.15 and 0.20 wt. % Zr in the form of the AlZr20 master alloy) on selected properties of AlSi5Cu2Mg aluminum alloy. This is [...] Read more.
The aim of this paper was to analyze the impact of the addition of different amounts of zirconium (0.05; 0.10; 0.15 and 0.20 wt. % Zr in the form of the AlZr20 master alloy) on selected properties of AlSi5Cu2Mg aluminum alloy. This is a new alloy for cylinder head castings and has only been used for a relatively short time. The specificity of this alloy is its chemical composition—specifically the low permitted Ti content, which makes it impossible to refine the grain structure of this alloy using standard Al-Ti-B grain refiners. The aim of our ongoing research is to find a suitable alloying element that would positively mainly affect the mechanical and also physical properties of this alloy, which are crucial for complex automotive castings such as cylinder heads. The results of our research showed that increasing zirconium content had no effect on the increase in ultimate tensile strength, yield strength and hardness of as-cast samples. After T7 heat treatment, a more significant increase in UTS, YS and thermal conductivity occurred due to the precipitation of Cu- and Mg-rich strengthening precipitates. Zirconium-rich intermetallic phases were observed in the shape of separate thick needles or as a cluster of two crossed thinner needles. SEM observations showed that these phases crystallized near to the intermetallic phases based on Cu and Fe. Increasing the Zr content was accompanied by an increase in liquidus temperature, the density index and the area fraction of porosity values. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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14 pages, 4366 KiB  
Article
Corrosion Resistance of L120G13 Steel Castings Zone-Reinforced with Al2O3
by Daniel Medyński and Jacek Chęcmanowski
Materials 2022, 15(12), 4090; https://doi.org/10.3390/ma15124090 - 09 Jun 2022
Cited by 2 | Viewed by 1185
Abstract
The aim of the study was to determine the effect of zone reinforcement of cast steel L120G13 with Al2O3 macro-particles on the corrosion resistance of the composite obtained in this way. The obtained results allow us to conclude that strengthening [...] Read more.
The aim of the study was to determine the effect of zone reinforcement of cast steel L120G13 with Al2O3 macro-particles on the corrosion resistance of the composite obtained in this way. The obtained results allow us to conclude that strengthening of cast steel with corundum, the aim of which was to significantly increase the abrasive wear resistance, did not significantly deteriorate corrosion resistance. SEM tests show that a permanent diffusion layer interface is formed at the boundary between cast steel and corundum. In this area, simple manganese segregation and reverse iron and chromium segregation were found. These elements pass from the liquid alloy to the surface layer of the corundum particles, causing the aluminium and oxygen to be pushed deep into the corundum grains. Corrosion tests indicate comparable corrosion resistance of cast steel L120G13 and the composite L120G13 + Al2O3. Moreover, no intergranular corrosion was found in the matrix of the composite and no signs of pitting corrosion were found in the areas of the interface between the phases of the composite. This information is extremely important from the point of view of the material’s service life. Observations of breakthrough of both materials obtained during fracture after potentiodynamic corrosion tests, immediately after freezing in liquid nitrogen, indicate cracking with plastic features and increased resistance to dynamic forces of cast steel L120G13 and the composite L120G13 + Al2O3. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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20 pages, 13698 KiB  
Article
Study of the Influence of Zirconium, Titanium and Strontium on the Properties and Microstructure of AlSi7Mg0.3Cu0.5 Alloy
by Dana Bolibruchová, Michal Kuriš, Marek Matejka and Justyna Kasińska
Materials 2022, 15(10), 3709; https://doi.org/10.3390/ma15103709 - 22 May 2022
Cited by 6 | Viewed by 1808
Abstract
The aim of the paper is to describe and specify the properties and microstructure of Al-Si alloy using Zr, a combination of Zr with elements used in the grafting of Al (Ti) alloys, and modification (Sr). Al-Si alloys with a combination of Zr [...] Read more.
The aim of the paper is to describe and specify the properties and microstructure of Al-Si alloy using Zr, a combination of Zr with elements used in the grafting of Al (Ti) alloys, and modification (Sr). Al-Si alloys with a combination of Zr and Ti and Sr elements represent an opportunity for the development of new aluminum alloys with a specific use. The experiment focused on the analysis of the synergistic effects of Zr with Ti and Zr with Sr on a AlSi7Mg0.3Cu0.5 alloy. The experimental alloys contained a constant Zr content of 0.15 wt. % and were alloyed with a gradual addition of Ti and Sr in the range of 0.1 to 0.3 wt. % for Ti, and 0.1 to 0.3 wt. % for Sr. The experimental samples were cast by meltable model casting technology. In variants with a constant addition of Zr 0.15 wt. % and a gradual addition of Ti, we observed an increase in the values of mechanical characteristics, with a significant decrease in ductility. When evaluating the structure of experimental alloys, Ti affected it by increasing the number of precipitated Zr phases. Experimental alloys with Zr and Sr addition were characterized by nucleation of Zr phases in angular morphology. It can be concluded that the investigated elements are expected to have a positive (strengthening) effect even at higher operating temperatures. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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20 pages, 7651 KiB  
Article
The Use of Barley Malt as a Binder in Molding Sand Technology
by Bartłomiej Samociuk, Daniel Medyński, Daniel Nowak, Joanna Kawa-Rygielska, Kacper Świechowski, Alan Gasiński and Andrzej Janus
Materials 2022, 15(9), 3375; https://doi.org/10.3390/ma15093375 - 08 May 2022
Viewed by 1557
Abstract
The aim of this study was to attempt to use barley malt as a natural, organic binder in the technology of molding sand. TGA analysis of the binder was performed, during which temperatures of thermal decomposition of its components were determined. The results [...] Read more.
The aim of this study was to attempt to use barley malt as a natural, organic binder in the technology of molding sand. TGA analysis of the binder was performed, during which temperatures of thermal decomposition of its components were determined. The results of TG/DTG analysis show that a loss of ~75% of mass of the MB binder is organic matter. Over 50% of this is starch. The results indicate the possibility of using a binder made of barley malt as a binding material for quartz sand grains. This fact was confirmed by tests carried out with use of SEM. During the observations, it was found that barley malt forms smooth bridges connecting individual grains of quartz sand. The typical properties of molding sands with barley malt were also determined, compared to sands containing commonly used binders. At the same time, the influence of the content of this binder on flowability, permeability, strength properties, and wear resistance was assessed. It has been found that increasing the binder content in molding mass results in an increase in strength and wear resistance, as opposed to flowability and permeability. Test castings were also made. It was found that the addition of a binder made of barley malt has a positive effect on the surface quality of castings. This was confirmed by roughness measurements of the test castings. At the same time, a tendency to excessive gas evolution during pouring was shown, with higher contents of this binder. Moreover, greater amounts of barley malt in the molding sand (MB 5%) as compared to the lower content (MB 2%) increased the thickness of the burnt layer of the sand by 25%. This is due to the exothermic reaction when more binder is burnt. It is extremely important from the point of view of the regeneration of molding sand. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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14 pages, 7118 KiB  
Article
Corrosion Behavior of SiMo Cast Iron under Controlled Conditions
by Marcin Stawarz and Paweł M. Nuckowski
Materials 2022, 15(9), 3225; https://doi.org/10.3390/ma15093225 - 29 Apr 2022
Cited by 2 | Viewed by 1367
Abstract
The resistance of cast iron to chemical and electrochemical corrosion depends on the exposure conditions, chemical composition and the distribution of alloying elements in the microstructure. The article presents an attempt to describe the formation of a corrosion layer under controlled chemical corrosion [...] Read more.
The resistance of cast iron to chemical and electrochemical corrosion depends on the exposure conditions, chemical composition and the distribution of alloying elements in the microstructure. The article presents an attempt to describe the formation of a corrosion layer under controlled chemical corrosion conditions for SiMo ductile iron. In the experiment, a (HT-HRD) chamber for heating the samples with a controlled atmosphere was used, at the same time providing the possibility of testing the sample surface using the XRD method. The analysis was both qualitative and quantitative. It allowed us to capture the sequence of the oxide layer growth on the tested samples. The beneficial effect of molybdenum on the corrosion resistance of SiMo cast iron has been proven. For all cases under analysis, the phenomenon of an increase in the share of hematite (Fe2O3) and magnetite (Fe3O4) was observed in the subsequent sample heating cycles. It turned out that the addition of molybdenum helps to create a tight oxide coating that inhibits the further growth of corrosion processes. Increasing the share of molybdenum in the alloy also reduces the thickness of the oxide layer. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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17 pages, 42180 KiB  
Article
Assessment of the Quality and Mechanical Parameters of Castings Using Machine Learning Methods
by Krzysztof Jaśkowiec, Dorota Wilk-Kołodziejczyk, Śnieżyński Bartłomiej, Witor Reczek, Adam Bitka, Marcin Małysza, Maciej Doroszewski, Zenon Pirowski and Łukasz Boroń
Materials 2022, 15(8), 2884; https://doi.org/10.3390/ma15082884 - 14 Apr 2022
Cited by 6 | Viewed by 1518
Abstract
The aim of the work is to investigate the effectiveness of selected classification algorithms and their extensions in assessing microstructure of castings. Experiments were carried out in which the prepared algorithms and machine learning methods were tested in various conditions and configurations, as [...] Read more.
The aim of the work is to investigate the effectiveness of selected classification algorithms and their extensions in assessing microstructure of castings. Experiments were carried out in which the prepared algorithms and machine learning methods were tested in various conditions and configurations, as well as for various input data, which are photos of castings (photos of the microstructure) or information about the material (e.g., type, composition). As shown by the literature review, there are few scientific papers on this subject (i.e., in the use of machine learning to assess the quality of the microstructure and the obtained strength properties of cast iron). The effectiveness of machine learning algorithms in assessing the quality of castings will be tested using the most universal methods. Results obtained by classic machine learning methods and by neural networks will be compared with each other, taking into account aspects such as interpretability of results, ease of model implementation, algorithm simplicity, and learning time. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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Review

Jump to: Research

24 pages, 5075 KiB  
Review
Adding Value to Secondary Aluminum Casting Alloys: A Review on Trends and Achievements
by Helder Nunes, Omid Emadinia, Rui Soares, Manuel F. Vieira and Ana Reis
Materials 2023, 16(3), 895; https://doi.org/10.3390/ma16030895 - 17 Jan 2023
Cited by 9 | Viewed by 2451
Abstract
Aluminum is a critical element of the circular economy as it can be recycled several times. Moreover, Al recycling is a more economically and environmentally efficient procedure than the primary Al production from ores. Secondary aluminum alloys are mostly used in casting applications [...] Read more.
Aluminum is a critical element of the circular economy as it can be recycled several times. Moreover, Al recycling is a more economically and environmentally efficient procedure than the primary Al production from ores. Secondary aluminum alloys are mostly used in casting applications since it is possible to accommodate their chemical composition through secondary manufacturing processes. However, the quality of the alloys may be considerably altered during the different steps of the recycling process. Inadequate waste sorting might result in excessive contamination. Iron is the most dangerous contaminant because it causes brittle and fragile intermetallic phases, which significantly impacts the mechanical characteristics of alloys. In addition, the microstructure of the alloy changes significantly after multiple cycles of remelting. These issues lead to the downcycling of aluminum, i.e., in other words, the reduction in the overall quality of the alloys. Thus, it has been shown that a number of procedures, including ultrasonic melt treatment and microalloying with rare earths, can somewhat alter the shape of the Fe-rich phases in order to reduce the shortcomings of downcycling. However, a solid mechanical characterization is still missing in order to improve the Fe-rich phase alteration. Full article
(This article belongs to the Special Issue Modern Foundry Materials and Technologies)
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