Applied sciences

Archives of Foundry Engineering

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Archives of Foundry Engineering | Ahead of print |

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Abstract

Though normal air cooling and green sand mold-casted gray iron convey an essentially pearlitic matrix, ferritic gray iron is used in some electro-mechanical applications to have better magnetic properties, ductility, and low hardness. Conventionally, to produce ferritic gray iron, foundryman initially produces pearlitic gray iron, then it is carried through a long annealing cycle process for ferritic transformation. This experiment is conducted to eliminate the long annealing cycle from the conventional process. A process is developed to produce as-cast ferritic gray cast iron by air cooling in the green sand mold. In this experiment, Si content is kept high, but Mn content is kept low based on sulfur content; a unique thermodynamic process is established for decreasing the Mn content from the melt. After a successful preconditioning and optimum foundry return charging, the melt is specially inoculated, and metal is poured into the green sand mold. An extra feeder is added for slowing down the cooling rate where casting thickness is around 15mm. Finally, hardness and metallographic images are observed for final confirmation of the ferritic matrix.
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Authors and Affiliations

Md Sojib Hossain
1

  1. Bangladesh University of Engineering and Technology, Shahbagh, Dhaka – 1000, Bangladesh
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Abstract

Protective coatings have direct contacts with hot and liquid alloys. As the result of such contacts gases are emitted from coatings. Gas forming is a tendency of the tested material to emit gases under a temperature influence. In order to assess the gas forming tendency either direct or indirect methods are applied. In the hereby work, the measurements of the gas forming tendency were performed under laboratory conditions, by means of the developed indirect method. The research material constituted samples of six selected protective coatings dissolved either in alcohol or in water. These coatings are applied in sand moulds and cores for making cast iron castings. The assessment of their gas forming tendency was presented in relation to temperatures and heating times. The occurrence and changes of oxygen and hydrogen contents in gases outflowing from the measuring flask during tests, were measured by means of gas sensors. The process of the carbon monoxide (CO) emission during tests was also assessed. The following gas sensors were installed in flow-through micro chambers: for oxygen - lambda probe, for hydrogen – pellistor, for carbon monoxide - sensor (dedicated for CO) FIGARO TGS 822 TF. The results of direct CO measurements were recalculated according to the algorithm supplied by the producer of this sensor.
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Authors and Affiliations

J. Mocek
1

  1. AGH University of Science and Technology, Faculty of Foundry Engineering, Department of Moulding Materials, Mould Technology and Cast Non-Ferrous Metals, Al. Mickiewicza 30, 30-059 Kraków, Poland
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Abstract

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.
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Authors and Affiliations

A.Y. Kaya
1
O. Özaydın
1
T. Yağcı
2
A. Korkmaz
2
E. Armakan
1
O. Çulha
2

  1. Cevher Alloy Wheels Co. / R&D Dept., İzmir, Turkey
  2. Manisa Celal Bayar University, Engineering Faculty, Dept. of Metallurgical and Materials Engineering, Manisa, Turkey
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Abstract

For the manufacture of near net shape complex titanium products, it is necessary to use investment casting process. Melting of titanium is promising to carry out by electron beam casting technology, which allows for specific processing of the melt, and accordingly control the structure and properties of castings of titanium alloys. However, the casting of titanium in ceramic molds is usually accompanied by a reaction of the melt with the mold. In this regard, the aim of the work was to study the interaction of titanium melt with ceramics of shell molds in the conditions of electron beam casting technology. Ceramic molds were made by using the following refractory materials – fused corundum Al2O3, zircon ZrSiO4 and yttria-stabilized zirconium oxide ZrO2, and ethyl silicate as a binder. Melting and casting of CP titanium was performed in an electron beam foundry. Samples were made from the obtained castings and electron microscopic metallography was performed. The presence and morphology of the altered structure, on the sample surface, were evaluated and the degree and nature of their interaction were determined. It was found that the molds with face layers of zirconium oxide (Z1) and zircon (ZS1) and backup layers of corundum showed the smallest interaction with the titanium melt. Corundum interacts with titanium to form a non-continuous reaction layer with thickness of 400-500 μm. For shell molds with face and backup layers of zircon on the surface of the castings, a reaction layer with thickness of 500-600 μm is formed. In addition, zirconium-silicon eutectic was detected in these layers.
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Authors and Affiliations

P. Kaliuzhnyi
1
M. Voron
1
O. Mykhnian
1
A. Tymoshenko
1
O. Neima
1
O. Iangol
1

  1. Physico-Technological Institute of Metals and Alloys of the National Academy of Sciences of Ukraine, Ukraine
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Abstract

The paper presents changes in the production volume of castings made of non-ferrous alloys on the background of changes in total production of casting over the 2000-2019 period, both on a global scale and in Poland. It was found that the dynamics of increase in the production volume of castings made of non-ferrous alloys was distinctly greater than the dynamics of increase in the total production volume of castings over the considered period of time. Insofar as the share of production of the non-ferrous castings in the total production of castings was less than 16% during the first two years of the considered period, it reached the level of 20% in the last four years analysed. This share, when it comes to Poland, increased even to the greater degree; it grew from about 10% of domestic production of castings to over 33% within the regarded 2000-2019 period. The greatest average annual growth rate of production, both on a global scale and in Poland, was recorded for aluminium alloys as compared with other basic non-ferrous alloys. This growth rate for all the world was 4.08%, and for Poland 10.6% over the 2000-2019 period. The value of the average annual growth rate of the production of aluminium castings in Poland was close to the results achieved by China (12%), India (10.3%) and the South Korea (15.4%) over the same period of time. In 2019, the total production of castings in the world was equal to about 109 million tonnes, including over 21 million tonnes of castings made of non-ferrous alloys. The corresponding data with respect to Poland are about 1 million tonnes and about 350 thousand tonnes, respectively. In the same year, the production of castings made of aluminium alloys was equal to about 17.2 million tonnes in the world, and about 340 thousand tonnes in Poland.
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Authors and Affiliations

M.S. Soiński
1
A. Jakubus
1

  1. The Jacob of Paradies University in Gorzów Wielkopolski, ul. Teatralna 25, 66-400 Gorzów Wielkopolski, Poland
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Abstract

This paper presents the study about defects found in industrial high silicon ductile iron. The microstructures were analysed using an optical microscope. Afterwards, a scanning electron microscope was used to analyse the chemical composition.The study also examined the origin of oxygen and what is the amount of oxygen in the cast iron.The amount of active oxygen was measured at two production processes. Firstly, at the end of melting process, and secondly, after the nodularization treatment. The research was carried out with different proportions of the raw materials. The focus was on determining the mechanism of the formation of slag defects to eliminate them in order to obtain ductile iron with increased silicon content of the highest possible quality. The research presented in this publication is a part of an implementation doctorate carried out in the METALPOL Foundry in Węgierska Górka (Poland). The presented research concerns the elaboration of initial parameters of liquid metal intended for processing into high-silicon ductile cast iron SiMo1000 type with aluminum and chromium additives.
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Authors and Affiliations

Ł. Dyrlaga
1 2
D. Kopyciński
1
E. Guzik
1

  1. AGH University of Science and Technology, Department of Foundry Engineering, Al. Mickiewicza 30, 30-059 Kraków, Poland
  2. METALPOL Węgierska Górka ul. Kolejowa 6, 34-350 Węgierska Górka, Poland
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Abstract

The article presents results of research on the influence of the mould material on selected mechanical properties of wax models used for production of casting in investment casting method. The main goal was to compare the strength and hardness of samples produced in various media in order to analyse the applicability of the 3D printing technology as an alternative method of producing wax injection dies. To make the wax injection dies, it was decided to use a milled steel and 3D printed inserts made using FDM (Fused Deposition Modeling) / FFF (Fused Filament Fabrication) technology from HIPS (High Impact Polystyrene) and ABS (Acrylonitrile Butadiene Styrene). A semi-automatic vertical reciprocating injection moulding machine was used to produce the wax samples made of Freeman Flakes Wax Mixture – Super Pink. During injection moulding process, the mould temperature was measured each time before and after moulding with a pyrometer. Then, the samples were subjected to a static tensile test and a hardness test. It was shown that the mould material influences the strength properties of the wax samples, but not their final hardness.
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Authors and Affiliations

A. Kroma
1
P. Brzęk
1

  1. Poznan University of Technology, Institute of Materials Technology, Division of Foundry, Piotrowo 3, 61-138 Poznań, Poland
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Abstract

The paper presents FEM approach for comparative analyses of wall connections applied in cast grates used for charge transport in furnaces for heat and thermal-chemical treatment. Nine variants of wall connection were compared in term of temperature differences arising during cooling process and stresses caused by the differences. The presented comparative methodology consists of two steps. In first, the calculations of heat flow during cooling in oil for analysed constructions were carried out. As a result the temperature distributions vs cooling time in cross-sections of analysed wall connections were determined. In the second step, based on heat flow analyses, calculations of stresses caused by the temperature gradient in the wall connections were performed. The conducted calculations were used to evaluate an impact of thermal nodes reduction on maximum temperature differences and to quantitative comparison of various base design of the cast grate wall connection in term of level of thermal stresses and their distribution during cooling process. The obtained results clearly show which solution of wall connection should be applied in cast grate used for charge transport in real constructions and which of them should be avoided because the risk of high thermal stresses forming during cooling process.
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Authors and Affiliations

A. Bajwoluk
1
P. Gutowski
1

  1. Mechanical Engineering Faculty, West Pomeranian University of Technology, Szczecin, Al. Piastów 19, 70-310 Szczecin, Polska
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Abstract

The paper is a summary of a project aimed at identifying and eliminating or minimizing the causes of frequent failures of the Krakow water supply network related to corrosion damage. The paper presents the method of searching for factors responsible for frequent corrosion damage. There were taken into account several factors that may destroy the pipes associated with corrosion processes, such as the composition of the water, aggressiveness of ground, or stray currents. The monitoring method of the corrosion processes applied to observe the condition of the water supply network was discussed. The study showed that the main problem appeared to be stray currents related to the electrical infrastructure widely present in a large city, such as a tram or railway network. To eliminate this threat, a cathodic protection system has been implemented to prevent further failures. There were also demonstrated results of research proving that the applied solutions are effective.
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Authors and Affiliations

U. Lelek-Borkowska
1

  1. AGH University of Science and Technology
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Abstract

Metallurgy is one of the key industries both in Russia and in the world. It has a significant influence on the situation in related industries. Therefore, the current state analysis of ferrous metallurgy production and its formation based on the short-term technological forecast is essential. Based on the foregoing, the research was aimed at analyzing the current state of ferrous metallurgy production in Russia and the impact of the COVID-19 pandemic on the prospects for industry development in the short term. The research studies the state of the ferrous metallurgy production in Russia and abroad before the COVID-19 pandemic, as well as the volume of industrial production in ferrous metallurgy and the industry structure. The COVID-19 pandemic has triggered a serious global recession, necessitating an analysis of the forecast for the development of the ferrous metallurgy industry. The research concludes that the Russian ferrous metals market is so far affected to a lesser extent compared to the European one.
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Authors and Affiliations

S.S. Golubev
1
V.D. Sekerin
1
A.E. Gorokhova
1
D.A. Shevchenko
1
A.Z. Gusov
2

  1. Moscow Polytechnic University, Bolshaya Semenovskaya Street, 38, Moscow, 107023, Russian Federation
  2. Peoples Friendship University of Russia (RUDN University), Miklukho-Maklaya Street, 6, Moscow, 117198, Russian Federation

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