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High temperature corosion of SiMo type ductile iron
Viskupič, Adam ; Kaňa, Václav (referee) ; Roučka, Jaromír (advisor)
While using iron castings behind temperature of 500 C namely at cyclic heat straining degradation of structure and breaching iron castings. For this purpose introduce cast iron with content of Si and Mo. Focusing on improvement of SiMo51 for increased high-temmperature corrosion-and fatigue life in exhaust-gas temperatures up to 800 C. Thesis set up chemical microheterogeneity, properties, high temperature corosion and microhardness
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Influence of zinc loss during the sintering on permeability/inductance of ferrite ceramics
Kvapilová, Vendula ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The diploma thesis is focused on the investigation of the effect of zinc release during ferritic sintering on the permeability/inductance of ferrite ceramics. The theoretical part deals with the position of ferrites among other ceramic materials. It describes the basic characteristics of ferrites, their crystal structure and finally the problems that are directly related to their production and which fundamentally affect the magnetic properties of ferrites. In the second part of the work, the influence of the temperature and time of sintering and the position of the cores in the furnace during firing on the loss of zinc from the sample and subsequently on the electromagnetic properties of the prepared test specimens from industrial raw material mixtures was investigated. These are initial experiments, which will be followed by further research aimed at eliminating the problem of zinc loss in the production of Mn-Zn ferrites.
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Mechanical properties of Nodular Cast Iron prepared by method Tundish and process Initek
Vítek, Radovan ; Hotový, Ivan (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis deals with a properties and production of nodular cast iron. The first section describes the classification, distribution and structure of nodular cast iron. The second part is focuses on the description of nodular cast iron, modification, inoculation and production. A strong effort is made on the production of nodular cast iron using the Tundish Cover method and the Initek process. In conclusion, the structure of the material is evaluated on samples that were delivered for metallographic analysis. The final evaluation of the structure of the material is used to compare the mechanical properties of a nodular cast iron produced by Tundish Cover method and Initek process.
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The study of degasing process during thermal treatment of advanced ceramic
Kocián, Karel ; Šoukal, František (referee) ; Ptáček, Petr (advisor)
This bachelor thesis deals with mechanism and kinetics of the burnout of additives during thermal treatment of ferrite ceramics. In order to establish this process thermal analysis were used, specifically: simultaneous thermogravimetric determination, differential thermal analysis and thermal analysis with evolved gas analysis (TG-DTA and EGA), high-temperature microscopy (HM), burning test in kiln with controlled atmosphere and high-temperature X-ray diffraction (HT-XRD). To determine the elemental composition after sintering and characterization of the sample, scanning electron microscopy (SEM) was used.
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Heat processing principle of operation thermal resistance annealing.
Špičková, Petra ; Humár, Anton (referee) ; Kalivoda, Milan (advisor)
The project assigned for the bachelors study program B 2307 analyses the theory of heat processing in general and furthermore resistance annealing with the focus on the technology developed by the company Heatmasters. Examples of processing methods used at other technology providers are presented, inclu-ding documentation and datasheets. Resistance annealing is based on the heat transfer from a resistive wire, which heats up by electrical current. The thermal energy is then transferred to the target material through heat radiation or con-ductance. The resistance heat processing is used both for welding and for an-nealing. Nowadays is the documentation and recording of the heat processing of significant importance. Possibilities exist that allow recording of temperature during the entire cycle of the heat processing and subsequently providing the result evidence in a form of a certificate.
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Metody tavného svařování pro výrobu ocelových nádrží na užitkovou vodu
Nevěděl, Jan
The folowing pages of bachelor thesis are talking about utilisation of fusion welding in water tank manufacture process. Due to the most frequent use of MIG, MAG and TIG welding types, this thesis will be largely focused on the above mentioned methods. Because of dynamical development of welding technologies thesis will look at economical side of fusion welding. Also will be talking about other fusion connecting types. In the other part of the thesis we will look at basic principles of welding and then its application in at technological processes, focused on behaviour at water tanks. The last part of the thesis will be centralized on rust protection and flaw detectection in welds. Whole labor is supported with photographs from water tank manufacture process.
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Influence of zinc loss during the sintering on permeability/inductance of ferrite ceramics
Kvapilová, Vendula ; Ptáček, Petr (referee) ; Šoukal, František (advisor)
The diploma thesis is focused on the investigation of the effect of zinc release during ferritic sintering on the permeability/inductance of ferrite ceramics. The theoretical part deals with the position of ferrites among other ceramic materials. It describes the basic characteristics of ferrites, their crystal structure and finally the problems that are directly related to their production and which fundamentally affect the magnetic properties of ferrites. In the second part of the work, the influence of the temperature and time of sintering and the position of the cores in the furnace during firing on the loss of zinc from the sample and subsequently on the electromagnetic properties of the prepared test specimens from industrial raw material mixtures was investigated. These are initial experiments, which will be followed by further research aimed at eliminating the problem of zinc loss in the production of Mn-Zn ferrites.
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Hyperfine Interactions in Ferrites with Spinel Structure
Chlan, Vojtěch
Title: Hyperfine Interactions in Ferrites with Spinel Structure Author: Vojtěch Chlan Faculty of Mathematics and Physics, Charles University in Prague Supervisor: Prof. RNDr. Helena Štěpánková, CSc. Abstract: Ferrite systems with spinel structure, manganese ferrite, lithium ferrite and magnetite, are studied experimentally by nuclear magnetic resonance (NMR) spectroscopy and from the first principles by electron structure calculations based on density functional theory (DFT). Manganese ferrites with various degrees of manganese-iron inversion and with different manganese contents are investigated, with respect to magnetic structure and cationic arrangement. An approach for NMR spectra interpretation is elaborated on ordered lithium ferrite, consisting in matching the calculated hyperfine field anisotropy with experimental results. This method is then applied to low temperature structure of magnetite, showing a promising path towards solving its complicated structure, orbital and charge ordering. The switching of magnetic easy axis induced by external magnetic field is observed in magnetite and the accompanying structural changes are studied by means of magnetic and NMR measurements. Magnetite with cationic vacancies is investigated by analyzing satellite structure induced by the vacancies; it is shown that...
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Vliv uhlíku na tepelné zpracování ocelových součástí
Šťastný, Vojtěch
Bachelor´s thesis deals with problematic of heat treatment and influence of carbon on properties of iron alloys. The beginning of the work describes the production process, input materials and equipment for the production of pig iron, cast iron and steel. There are also described elements influencing properties of steels, definition and distribution of cast iron and steel. The thesis deals with heat treatment and its types. In the thesis thereis also described diagram iron-iron carbide (Fe-Fe3C) and its individual structural phases. The next part of the thesis deals with problematic of transformaci on diagrams. The last part of the thesis deals with the transformations of cooled austenit and its individual species.
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