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Inclusions in steel castings
Kaněra, Miloš ; Šenberger, Jaroslav (referee) ; Pernica, Vítězslav (advisor)
This thesis presents basic knowledge and dividing about inclusions which, by their presence, influence quality and used property of steel casts. With focusing on basic group of exogenous and endogenous inclusions, the abstract of shapes was made as well as composition, condition for emergence and the reaction of melt which is in touch with surrounding impacts. The presence of characteristic inclusions influence technological dimension containing formability or fatigue behaviour falling into mechanical dimension. Constantly growing demands increase the importance of prevention, eventually reduction of impurity fraction with the help of steel refinement or inclusion modification. Success of suggested arrangements for quality improving is analysed by the following methods of identification.
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Manufacture of heavy steel castings
Klváček, Jan ; Pernica, Vítězslav (referee) ; Záděra, Antonín (advisor)
The aim of this bachelor thesis is perform a search on the topic of heavy castings of the steel. Production of heavy castings is a special part in manufacturing steel castings. Their properties are extremely influenced by a long time, which results in the creation of many metallurgical casting defects. Heavy castings are produced in small series or just a piece production. There-fore not possible remove defects during the manufacturing process. For the production of heavy castings are required specific requirements for this reason.
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Manufacture of bells
Dušek, Otakar ; Šenberger, Jaroslav (referee) ; Pernica, Vítězslav (advisor)
The bachelor thesis titled „Manufacture of bells” contains basic information about the historical development of bells, acoustic characteristics of the bells and particular processes accompanying their production. There are in detail particular phases of production and necessary equipment described in this work. The text also deals with the materials that are used for bells manufacturing. The analysis of the bell metal is the most discussed issue in this part, since it is the best and most widely used material for these purposes.
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Secondary metallurgy in foundries
Klika, Jiří ; Šenberger, Jaroslav (referee) ; Pernica, Vítězslav (advisor)
The aim of this bachelor thesis is to write a literary research about various methods of secondary metallurgy. In the thesis is described principle of methods and its advantages and disadvantages after installation in the manufactory, especially principle of steelmaking methods. It mainly concerns advantages of secondary metallurgy as degassing, decarburisation, desulphurisation and chemical or heat homogenization of liquid metal in the ladle.
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Furnaces used for manufacturing of castings from non-ferrous alloys
Jagošová, Adriana ; Pernica, Vítězslav (referee) ; Bořil, Petr (advisor)
This bachelor thesis focuses on the issue of furnaces used for casting non-ferrous alloys. The first chapter describes the properties of foundry alloys in general, the specific foundry properties of selected non-ferrous alloys and the principle of melt during their casting. The second chapter describes the criteria that are important for comparing furnaces work and for their selection. The third chapter lists the furnace distribution in terms of heating. The main part of the thesis is the fourth chapter, which includes the distribution and detailed description of the melting and maintenance furnaces, as well as the non-ferrous alloy heat treatment furnace.
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Production and properties of advanced Cu-based alloys castings
Kryštůfek, Tomáš ; Pernica, Vítězslav (referee) ; Kaňa, Václav (advisor)
This bachelor thesis is focused on well-arranged processing of production copper alloy castings. Following a brief historical introduction, a process of producing crude copper is first developed. Attention is paid to the sources of copper in nature and the subsequent melting of copper in furnace and converter. Furthermore, the technology of melting copper alloys is elaborated meaning melting devices, melting gases, melting directions and deoxidation. Very high purity copper can be produced by refining the crude copper in an electrolyte or by electroslag remelting and melted according to three technological processes. There are finally elaborated the processes of melting, properties and use of bronze and brass in detail - foundry copper alloys.
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Cleanliness of steels manufactured in vacuum induction furnaces
Pastyřík, Petr ; Záděra, Antonín (referee) ; Pernica, Vítězslav (advisor)
The topic of this thesis is the micropurity of steels manufactured in vacuum induction furnaces. The thesis describes 3 processes of steel melting using the same type of steel with different production parameters. Subsequently, samples were prepared and based on those samples the micropurities of the melting processes were evaluated. To obtain the results image analysis and electron microscope were used. Furthermore, elemental analyzer was used to measure the content of oxygen, nitrogen, sulphur and carbon. Afterwards, a discussion on micropurity and comparison of the melting processes is presented. In the conclusion section there are some possible suggestions concerning operation of the university foundry.
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Application of magnesium alloys castings
Pernica, Vítězslav ; Liškutín, Petr (referee) ; Roučka, Jaromír (advisor)
Magnesium alloys are still idle in technical applications because of their properties. The history of metal is not very old, the first application of its alloy started on the beginning of the 20th century. Magnesium is very light. Its weight is about one third less than the weight of aluminum and it is the third most frequented structural metal. However its preparation and processing can be problematical because magnesium has high affinity to oxygen. It causes intensive burning. During the century of stature have been improved both production and alloys. The usage of magnesium alloys took more importance and it is the most used alloy in automotive field sofar. Recently its demand expands mainly in electrotechnics. Next usage we can find in aeronautics, energetics, military and many other branches.
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Casting technology in bell founding
Šromota, Michal ; Pernica, Vítězslav (referee) ; Janský, Vojtěch (advisor)
The topic of the bachelor’s thesis, which comprises of theoretical and practical part, is campanology. The purpose was to summarize the technology of the bells’ manufacture from both, current and historical viewpoints. Basis of the theoretical part is literary recherche which describes the whole process of the bell’s manufacturing, material used for its casting, acoustic features of the bell, history of the industry and parts which are integral part of the bell. The recherche was composed mainly based on Czech academic literature, nonetheless, to a lesser extent, abroad resources were included too. Within the framework of the practical part a bronze bell was casted by a lost wax method with the contribution of 3D print.
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