Publikační činnost Katedry metalurgie a slévárentví / Publications of Department of Metallurgy and Foundry (618)

Permanent URI for this collectionhttp://hdl.handle.net/10084/64732

Kolekce obsahuje bibliografické záznamy publikační činnosti (článků) akademických pracovníků Katedry metalurgie a slévárenství (618) v časopisech registrovaných ve Web of Science od roku 2003 do roku 2022.
Do kolekce jsou zařazeny:
a) publikace, u nichž je v originálních dokumentech jako působiště autora (adresa) uvedena Vysoká škola báňská-Technická univerzita Ostrava (VŠB-TUO),
b) publikace, u nichž v originálních dokumentech není v adrese VŠB-TUO uvedena, ale autoři prokazatelně v době jejich zpracování a uveřejnění působili na VŠB-TUO.

Bibliografické záznamy byly původně vytvořeny v kolekci Publikační činnost akademických pracovníků VŠB-TUO, která sleduje publikování akademických pracovníků od roku 1990.

Od 1.1.2012 sloučena Katedra metalurgie (618) s Katedrou slévárenství (632).

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Now showing 1 - 20 out of 129 results

Technological and quality aspects of the use of innovative inorganic binders in the production of castings
(MDPI, 2021) Obzina, Tomáš; Merta, Václav; Folta, Martin; Bradáč, Josef; Beňo, Jaroslav; Novohradská, Nikol; Gawronová, Martina; Kroupová, Ivana; Lichý, Petr; Radkovský, Filip; Janovská, Kamila; Vasková, Iveta; Drobíková, Klára; Nguyenová, Isabel
The production of cores for the pre-casting of holes in castings places high demands on the quality of the molding mixtures used. For this reason, organic binders are still used to a large extent, which, although they meet the technological requirements, are a source of pollutant emissions during the production of castings. The current trend towards greening production is therefore looking for a suitable alternative in 'green' inorganic binders. Although for many decades standard inorganic binders could not be compared with organic resins in terms of technological properties, new inorganic binder systems are currently being developed that can largely eliminate these disadvantages, which include, in particular, significantly lower collapsibility and reclaimability, and lower mechanical strength values. Last but not least, the use of these binder systems may be limited by the technological parameter of shelf-life, which is the main focus of this study. The aim of this paper is to evaluate the influence of technological parameters of core production using a new generation of inorganic binder systems on their shelf-life. Shelf-life, defined as the change in mechanical strength and wear resistance as a function of exposure time in a given environment, is evaluated under different climatic conditions.
Preparation of cast metallic foams with irregular and regular inner structure
(MDPI, 2021) Kroupová, Ivana; Gawronová, Martina; Lichý, Petr; Merta, Václav; Radkovský, Filip; Janovská, Kamila; Nguyenová, Isabel; Beňo, Jaroslav; Obzina, Tomáš; Vasková, Iveta; Lána, Ivo; Rygel, Jiří
The aim of this paper is to summarize the possibilities of foundry methods for the production of metallic foams. At present, there are a number of production technologies for this interesting material, to which increasing attention has been paid in recent years. What is unique about metallic foams is the combination of their physical and mechanical properties. As part of our research, we designed and verified four main methods of metallic foam production by the foundry technology, whose products are metallic foam castings with regular and irregular arrangements of internal cavities. All these methods use materials and processes commonly used in conventional foundry technologies. The main idea of the research is to highlight such technologies for the production of metallic foams that could be provided by manufacturing companies without the need to introduce changes in production. Moreover, foundry methods for the production of metallic foams have the unique advantage of being able to produce even complex shaped parts and can thus be competitive compared to today's established technologies, the output of which is usually only a semi-finished product for further processing. This fact was the main motivation for the research.
Innovative inorganic binder systems for the production of cores for non-ferrous metal alloys reflecting the product quality requirements
(MDPI, 2021) Merta, Václav; Beňo, Jaroslav; Obzina, Tomáš; Radkovský, Filip; Kroupová, Ivana; Lichý, Petr; Folta, Martin; Janovská, Kamila; Nguyenová, Isabel; Dostal, Miroslav
The aim of this study is the evaluation of the parameters of core mixtures using different binder systems with regard to the collapsibility of cores after casting and the resulting product quality of castings reflecting surface requirements based on non-ferrous alloys. The research compares organically bonded core mixtures based on phenol-formaldehyde resins for the production of cores with the shell molding (resin coated sand), currently used in the production of aluminum alloy castings in the Brembo Czech s.r.o., and mixtures using innovative inorganic binder systems based on geopolymers; GEOPOL(R) W. The aim of the research is to compare the advantages and disadvantages of these binder systems in order to evaluate the potential of inorganically bonded mixtures to replace organically bonded mixtures, which would lead to a significant reduction in the environmental impacts of industrial production of castings.
Design of proven technology of metal foam and porous metal casting production
(Polska Akademia Nauk, Oddział PAN w Katowicach, 2021) Radkovský, Filip; Merta, Václav; Obzina, Tomáš
The article describes the design of a proven technology for the production of metal foam and porous metal by the foundry. Porous metal formed by infiltrating liquid metal into a mould cavity appears to be the fastest and most economical method. However, even here we cannot do without the right production parameters. Based on the research, the production process was optimised and subsequently a functional sample of metal foam with an irregular internal structure - a filter - was produced. The copper alloy filter was cast into a gypsum mould using an evaporable model. Furthermore, a functional sample of porous metal with a regular internal structure was produced - a heat exchanger. The aluminium alloy heat exchanger was cast into a green sand mould using preforms. Also, a porous metal casting with a regular internal structure was formed for use as an element in deformation zones. This aluminium alloy casting was made by the Lost Foam method. The aim is therefore to ensure the production of healthy castings, which would find use in the field of filtration of liquid metal or flue gases, in vehicles in the field of shock energy absorption and also in energy as a heat exchanger.
Some possibilities of using statistical methods while solving poor quality production
(Polska Akademia Nauk, Oddział PAN w Katowicach, 2021) Lakomá, Renáta; Čamek, L.; Lichý, Petr; Kroupová, Ivana; Radkovský, Filip; Obzina, Tomáš
This paper presents an overview of a research on six practical cases that were solved in a precise casting company where parts are cast by the mean of the low-wax casting method (investment casting) in order to decrease poor quality production. The steel cast parts production technology by the lost-wax method requires the detailed work procedures observation. On the base of statistical processing data of given types of casting products, it was possible to assess the significance of each particular checking events by using the statistical hypothesis testing. The attention was focused on wax and ceramic departments. The data in technological flow were compared before and after the implementation of the change and statistical confirmative influences were assessed. The target consisted in setting such control manners in order to get the right conditions for decreasing poor quality parts. It was evidenced that the cast part defect cause correct identification and interpretation is important.
Modelling of technological parameters of aluminium melt refining in the ladle by blowing of inert gas through the rotating impeller
(MDPI, 2021) Walek, Josef; Michalek, Karel; Tkadlečková, Markéta; Saternus, Mariola
The presented paper deals with the use of physical modelling to study the degassing process of aluminium melts in the refining ladle by blowing inert gas through a rotating impeller. For the purposes of physical modelling, a plexiglass model in a scale of 1:1 is used for the operating ladle. Part of the physical model is a hollow shaft used for gas supply that is equipped with an impeller and two baffles. The degassing process of aluminium melt by blowing of inert gas is simulated at physical modelling by a decrease of dissolved oxygen in the model liquid (water). This paper is aimed at the evaluation of laboratory experiments that were obtained by the method of physical modelling. Attention is focused on the assessment of relevant parameters for the degassing process-rotary impeller speeds, volume flow rate of inert gas, the distance of the impeller from the bottom of the refining ladle, and impeller variant. The preliminary results of physical modelling show that the optimal results of the refining process are achieved by using the F2A 190 impeller.
Numerical analysis of RTD curves and inclusions removal in a multi-strand asymmetric tundish with different configuration of impact ad
(MDPI, 2020) Tkadlečková, Markéta; Walek, Josef; Michalek, Karel; Huczala, Tomáš
To effectively remove non-metallic inclusions from the steel during the flowing in a five-strand asymmetric tundish, the novel configuration of the impact pad was developed. For analysis, complex numerical modelling in the programme ANSYS Fluent was used. The Lagrangian Discrete Phase Model of inclusion tracking was applied. The distribution of inclusions, with sizes ranging from 2 mu m to 100 mu m and density from 2500 to 3500 kg center dot m(-3), was considered only through the shroud tube. The residence time distribution (RTD) curves and inclusion removal efficiency were used for evaluation of steady state steel flow character depending on internal configuration of a tundish with an impact pad in two design modifications (Modification 1-M1, Modification 2-M2). The preliminary results showed that in the case of asymmetric geometry plays a role the computational mesh independency. The assembly method with cut cell approach was satisfactory even when the tundish geometry was changed. The RTD curves with an M1 showed a huge dead volume in the tundish. In the case with an M2, the RTD curves are more or less uniform for all casting strands, and the removal of inclusions to slag increased from about 55% up to 70% in comparison with M1.
Refining aluminium-alloy melts with graphite rotors
(Inštitut za kovinske materiale in tehnologije, 2020) Lichý, Petr; Bajerová, Markéta; Kroupová, Ivana; Obzina, Tomáš
The presented paper is focused on the study of refining aluminium-alloy melts. The quality of castings is determined by the basic material, i.e., the input material (furnace charge), its subsequent melting and subsequent metallurgical modifications. To allow the profitability of production, low-quality input materials are currently used, which, although they have the required chemical composition, may contain a large amount of impurities, coming not only from the original input materials, but also from their processing. To allow a cost reduction, in addition to rejected castings, the residues of gating and chipping from the machining are used as charge materials in foundries. However, the melt thus prepared is heavily contaminated with gases and inclusions.The aim of the research was, therefore, to verify the use of graphite rotors functioning as degassing units for refining aluminium melts. The experiments were conducted under laboratory and pilot-plant conditions using the plant equipment. The refining efficiency was monitored with respect to the type and shape of the graphite rotor and the refining medium used. The achieved purity of the resulting melt was evaluated to establish the density index and the final cast microstructure.
Use of numerical simulation in the production of porous-metal castings
(Inštitut za kovinske materiale in tehnologije, 2020) Radkovský, Filip; Merta, Václav
The article describes the design and optimization of the foundry production of porous metal. The formation of porous metal by infiltrating liquid metal into the mould cavity appears to be the fastest and most economical way. However, it is not possible to do it without proper production parameters. For this reason, a 3D model of a particular casting is first created in the Rhinoceros 4.0 software and then the entire production process is designed and optimized using the numerical simulation in the MAGMASOFT (R) 5.4 software. To create cavities in the casting, the use of sand cores is considered and the used unit bentonite mixture (UBM) becomes the mould material. With the simulations of pouring and solidification of the casting, the right conditions for the real production can be defined precisely; the time and financial costs connected with the production of non-conforming pieces can be saved. Thus, the aim is to ensure the production of sound castings that will find their use in the field of energy, specifically as heat exchangers.
Use of water-soluble precursors in the production of cast metal foams
(Inštitut za kovinske materiale in tehnologije, 2020) Kroupová, Ivana; Lichý, Petr; Lána, Ivo
The paper is devoted to the field of manufacturing cast metallic foams - porous metal materials - with a stochastic arrangement of the inner cavities. The mastering of inexpensive ways of manufacturing metallic foams is a prerequisite for a full utilization of such a material. That is why the experimental part was devoted to the casting technologies for the production of metal foams based on conventional foundry processes. In the experiment, the infiltration of molten metal into mould cavities filled with precursors was tested. Particular attention was paid to the use of water-soluble precursor materials. It is assumed that a thorough knowledge of the production parameters and conditions will contribute to the expansion of the foundry range, which can also increase the competitiveness of this industry on a global scale.
Manufacturing of cast-metal sponges from copper alloys
(Inštitut za kovinske materiale in tehnologije, 2020) Merta, Václav; Lána, Ivo
The paper deals with the topic of manufacturing metal sponges from copper alloys using a special foundry technology of "a two-stage investment-casting process using an evaporative polyurethane (PUR) pattern". Particular attention is paid to the study of castability as a technological characteristic, which is a limiting factor for the production of such castings. The castability of the CuSn12 copper alloy was observed in various production-process conditions (pouring temperature, mould temperature) with the aim to find dependence trends and set the optimal conditions of the manufacturing process. From the results, it is obvious that the crucial factor influencing the castability is the mould temperature, although the pouring temperature also has a smallish influence on it.
Numerical modelling of metal melt refining process in ladle with rotating impeller and breakwaters
(Polska Akademia Nauk, Instytut Metalurgii i Inżynierii Materiałowej, 2019) Sviželová, Jana; Tkadlečková, Markéta; Michalek, Karel; Walek, Josef; Saternus, Mariola; Pieprzyca, Jacek; Merder, Tomasz
The paper describes research and development of aluminium melt refining technology in a ladle with rotating impeller and breakwaters using numerical modelling of a finite volume/element method. The theoretical aspects of refining technology are outlined. The design of the numerical model is described and discussed. The differences between real process conditions and numerical model limitations are mentioned. Based on the hypothesis and the results of numerical modelling, the most appropriate setting of the numerical model is recommended. Also, the possibilities of monitoring of degassing are explained. The results of numerical modelling allow to improve the refining technology of metal melts and to control the final quality under different boundary conditions, such as rotating speed, shape and position of rotating impeller, breakwaters and intensity of inert gas blowing through the impeller.
Gas evolution of GEOPOL (R) W sand mixture and comparison with organic binders
(Polska Akademia Nauk, Oddział PAN w Katowicach, 2019) Vykoukal, Michal; Burian, Alois; Přerovská, Markéta; Bajer, Tomáš; Beňo, Jaroslav
The article deals with the gas development of the geopolymer binder system hardened by heal and provides the comparison with organic binder systems. The GEOPOL (R) W technology is completely inorganic binder system, based on water. This fact allow that the gas generated during pouring is based on water vapour only. No dangerous emissions, fumes or unpleasant odours are developed. The calculated amount of water vapour generated from GEOPOL (R) W sand mixture is 1.9 cm(3)/g. The measured volume of gas for GEOPOL (R) W is 4.3 cm(3)/g. The measurement of gas evolution proves that the inorganic binder system GEOPOL (R) W generates very low volume of gas (water vapour) in comparison with PUR cold box amine and Croning. The amount of gas is several times lower than PUR cold box amine (3.7x) and Croning (4.2x). The experiment results are consistent with the literature sources. The difference between the calculated and the measured gas volume is justified by the reverse moisture absorption from the air after dehydration during storing and preparing the sand samples. Minimal generated volumes of gas/water vapour brings, mainly as was stated no dangerous emissions, also the following advantages: minimal risk of bubble defects creation, the good castings without defects, reduced costs for exhaust air treatment, no condensates on dies, reduced costs for cleaning.
Influence of silica sand on surface casting quality
(Polska Akademia Nauk, Oddział PAN w Katowicach, 2019) Beňo, Jaroslav; Adamusová, Kristina; Merta, Václav; Bajer, Tomáš
The current casting production of castings brings increased demands for surface and internal quality of the castings. Important factors, that influence the quality of castal components, are the materials used for the manufacture of moulds and cores. For the preparation and production of moulds and cores, in order to achieve a low level of casting defects, then it used a high quality input materials, including various types of sands, modified binders, additives, etc. However, even the most expensive raw materials are not a guarantee to achieve the quality of production. It is always necessary to choose the appropriate combination of input material together with an appropriate proposal for the way of the production, the metallurgical treatment of cast alloy, etc. The aim of this paper is to establish the basic principles for the selection of the base core mixtures components - sands to eliminate defects from the tension, specifically veining. Various silica sand, which are commonly used in foundries of Middle Europe region, were selected and tested.
Use of precursors for the production of cast metallic foams
(Inštitut za kovinske materiale in tehnologije, 2019) Kroupová, Ivana; Lichý, Petr; Merta, Václav; Lána, Ivo
The presented work was devoted to the development of the production processes for metallic foams, which were based on conventional casting technologies. The use of the standard casting processes and standard materials made it possible to identify the range of metallic foams amongst affordable materials, thereby making a full use of their application potentials. The experimental part was focused on the development and subsequent optimization of the casting processes for manufacturing cast metallic foams with irregular inner-cell structures, and especially on the development of the technology of infiltrating molten metal into a mold cavity filled with precursors.
GEOPOL®. The innovated environment friendly inorganic binder system
(Polska Akademia Nauk, Oddział PAN w Katowicach, 2019) Vykoukal, Michal; Burian, Alois; Přerovská, Markéta
This paper deals with the complete technology of inorganic geopolymer binder system GEOPOL® which is a result of long term research and development. The objective of this paper is to provide a theoretical and practical overview of the GEOPOL® binder system and introduce possible ways of moulds and cores production in foundries. GEOPOL® is a unique inorganic binder system, which is needed and welcomed in terms of the environment, the work environment, and the sustainable resources. The GEOPOL® technology is currently used in the foundries for three basic production processes/technologies: (1) for self-hardening moulding mixtures, (2) sand mixtures hardened by gaseous carbon dioxide and (3) the hot box technology with hot air hardening. The GEOPOL® technology not only solves the binder system and the ways of hardening, but also deals with the entire foundry production process. Low emissions produced during mixing of sand, moulding, handling, and pouring bring a relatively significant improvement of work conditions in foundries (no VOCs). A high percentage of the reclaim sand can be used again for the preparation of the moulding mixture.
Production of cast porous metal
(Inštitut za kovinske materiale in tehnologije, 2019) Radkovský, Filip; Merta, Václav
The article deals with the foundry methods of manufacturing porous metal; it is focused on the materials with a regular arrangement of internal cells. Currently. there are many fields dealing with the problem of porous metals by either optimizing the already known technologies, developing new ones or using porous metals. The production of a porous metal with a regular structure of cells and the possibility of its functional usage are the main subjects of this article. Due to their shapes, sizes and distribution of internal pores, cast porous metals exhibit various properties including reduced weight, sufficient strength, an ability to absorb impact energy, a possibility to conduct heat, etc., that allow a wide range of applications in the areas such as construction. transport or power engineering.
Evaluation of properties of cast metal foams with irregular inner structure
(Polska Akademia Nauk, Instytut Metalurgii i Inżynierii Materiałowej, 2018) Kroupová, Ivana; Lichý, Petr; Ličev, Lačezar; Hendrych, Jakub; Souček, Kamil
Internal structure of metal foams is one of the most important factors that determine its mechanical properties. There exists a number of methods for studying the nature of the inner porous structure. Unfortunately most of these processes is destructive and therefore it is not possible to reuse the sample. From this point of view, as a suitable method seems to be the ability of using the so-called X-ray microtomography (also micro-CT). This is a non-destructive methodology used in a number of fields (industry, science, archaeology, medicine) for a description of the material distribution in the space (e.g. pores, fillers, defects, etc.). In principle, this technology works on different absorption of X-ray radiation by materials with changing proton number. The contribution was worked out in collaboration with experts from the Faculty of Electrical Engineering and Computer Science of the VSB-Technical University of Ostrava and it is focused on the analysis of internal structure of the metal foam casting with irregular arrangement of internal pores by using micro-CT. The obtained data were evaluated in the commercial software VGStudio MAX 2.2 and in the FOTOMNG system. For the evaluation of these data a new specialized module was introduced in this system. Several methods of pre-processing the image was prepared for the measurement. This preliminary processing consists, for example, from a binary image thresholding for better diversity between the internal porosity and the material itself or functions for colour inversion.
Optimizing of metal foam design for the use as a heat exchanger
(Polska Akademia Nauk, Instytut Metalurgii i Inżynierii Materiałowej, 2018) Radkovský, Filip; Gebauer, Marek; Merta, Václav
The work deals with possibilities of using this specific material. It is focused on cast metal foams with a regular arrangement of internal cells and it refers to already used casting technologies - the production of metal foamswith the aid of sand cores. Metal foamsare used in many industries, such as: automotive, aerospace, construction, power engineering. They have unique propertiesand due to lower weight with sufficient strength and greater contact surface can be used, for example, for the conduction of heat. This article deals with the useof the metal foam as a heat exchanger. The efficiency of the heat exchanger depends on its shape and size and therefore the study is focused first on the optimization of the shape before the proper manufacture.
Environmental life cycle assessment of electric vehicles in Poland and the Czech Republic
(Elsevier, 2018) Burchart-Korol, Dorota; Jursová, Simona; Folęga, Piotr; Korol, Jerzy; Pustějovská, Pavlína; Blaut, Agata
Electric vehicles (EVs) are the future of road transport in both Poland and the Czech Republic and offer significant potential for reducing air pollution and increasing life comfort, especially in crowded city centers. This paper presents a comparative life cycle assessment (LCA) of EVs in Poland and the Czech Republic, considering the life cycle from cradle to grave, with a special focus on the production of the electricity required to charge EV batteries. The analyses included the current and future energy systems (from 2015 to 2050) used to charge EV batteries in the both countries. A comparative analysis of EVs and passenger vehicles with internal combustion engines (ICEVs) was carried out. In addition, the analyses considered scenarios of smart grids from which the energy for the charging of EV batteries could be supplied exclusively from renewable sources. The results showed that the environmental burden of current and future EVs is higher in Poland than in the Czech Republic for all analyzed impact categories and that this result is primarily related to the type of electricity used to charge EV batteries. The comparative analysis of EVs and ICEVs showed that greenhouse gas (GHG) emissions and fossil fuel depletion in Poland and the Czech Republic, both at present and in the future, will be lower in the case of EVs than in the case of ICEVs. However, the acidification, eutrophication, human toxicity, and particulate matter formation caused by EVs are higher than those caused by ICEVs. The results showed that EVs coupled with renewable electricity sources offer the potential to reduce the negative impacts on the environment. It was concluded that the main determinant of the environmental impact of EVs is the type of electricity used to charge EV batteries. This is the first attempt at a comparative LCA of EVs in Poland and the Czech Republic. It is also the first approach that includes analyses of the LCA for both the present and future electricity production systems used for charging EV batteries.

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