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Manufacturing of thin-walled castings
Hýža, Radek ; Petřík, Michal (referee) ; Myška, Martin (advisor)
The thesis deals with fluidity. It is a phenomenon in the production of thin walled castings. Grey cast iron is a material with exceptional fluidity suited for making thin-walled casting of solid fuel boiler lids. This paper discusses the production options, of which is selected gravity casting into a sand mould bonded with the Geopol system. Furthermore, the theoretical section provides a general overview of fluidity and explores the specifics of grey cast iron fluidity. Lastly, it mentions different approaches to producing thin-walled castings focused on the fluidity of alloys. The practical part of the thesis focuses on designing test castings of the lids, creating the model devices and fabrication of four castings - two lids with 7 mm and 5 mm walls and two tests of fluidity with variations in casting temperature. All castings are made from ČSN 42 2410. The thesis provides the inputs required to produce a functional thin walled casting, identifying defects that can be repaired by adjusting the technological parameters.
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Fading of the inoculation in graphitic cast irons
Doubrava, Jiří ; Jelínek, Radim (referee) ; Záděra, Antonín (advisor)
The bachelor thesis is focused on the structure and properties of cast iron with flake graphite. In the theoretical part the problems of crystallization of cast irons, grafting, methods of grafting of graphitic cast irons are discussed. In the practical part, the time course of grafting structure in cast iron with flake graphite was verified. Two inoculations were verified and the fading effect of the inoculations was also determined. For this purpose, samples were taken continuously at regular time intervals. To check the disappearance of the grafting effect, the method of turbidity test, thermal analysis, chemical analysis and then metallographic smear were chosen to observe the structure and evaluate the image analysis.
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Effect of lead and antimony on the degradation of graphite shape in cast iron
Hlobil, Albert ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
The bachelor thesis focuses on the effect of lead and antimony on the degradation of graphite in cast iron in relation to the lowered mechanical characteristics. This leads to the subsequent summary of the formation of degraded structures and unfavourable elements – the elements that are the cause of the formation. In the practical segment of the thesis, I will prove the effects of lead (or the combination of lead and antimony) on the degradation of graphite in cast iron with the focus lying at flake graphite. Furthermore, the thesis examines the mechanical characteristics and the attenuation of cast iron in relation to the formation of degraded graphite structures.
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The study of increase in efficiency of manufacturing preparation of technology
Šudoma, Michal ; Lána, Ivo (referee) ; Jurová, Marie (advisor)
This paper discusses different alternatives of more efficient preparation of spheroided graphite cast iron production. Secondary metallurgy and chemical heating technology are used to recast cast iron fused in copula furnace. The work applies the known physical-chemical rules used in the production of quality spheroided graphite cast iron in regular production conditions. Based on the previous developments, the aim was to prepare implementation of verified secondary metallurgy processes in adjusted casting ladle. The casting ladle was adjusted in order to allow execution of all processes required in order for the relevant standards and material lists requirements to be met in respect to spheroided graphite cast iron quality. Comments regarding the trends in ferroalloy metallurgy and related marketing approach of the company. The work is concluded by a summary of advantages brought in by the new approaches compared to the traditional ones from the economical as well as environmental perspective.
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Assessment of probable causes of corrosion damage of a mould made of cast iron
Sobola, Petr ; Pantělejev, Libor (referee) ; Man, Ondřej (advisor)
Bachelor’s thesis deals with solution of problems on glass moulds, which were exposed to the corrosion medium for up to two days causing their damage. The thesis contains theoretical analysis of the problem, layout for the corrosion experiment and its execution. Based on the experiment a conclusion was pronounced that the extent of damage which was observed was not able to be created by corrosion of initial surface without any previous defect.
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Prediction of mechanical properties of lamelar iron castings by means of numerical simulation
Filipek, Szymon ; Hrouzek, Petr (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis was to assess the degree of conformity between the mechanical properties evaluated by numerical simulation in software MAGMA5 and the measured values of hardness and ultimate tensile strength of lamellar graphite iron castings. The theoretical part of this thesis deals with the classification of cast iron, structural components of lamellar graphite iron, and the factors defining the resulting mechanical properties of the material. The practical part presents an attempt to find empirical dependencies between input parameters and results evaluated by simulation software. At the end, an analysis of the correlation between reality and simulation software is performed.
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Penetration of metal into green sand during pouring of iron castings
Ptáček, Tomáš ; Neudert, Alois (referee) ; Záděra, Antonín (advisor)
This diploma thesis deals with the creation of penetration of cast iron with graphite casting cast into bentonite molds. In the first part of the thesis is theoretically described the formation of penetration, its main causes, consequences and the elimination of this defect. The second part analyzes the causes of the defect with the Minitab statistical software and shows the possible connections of the input materials to the occurrence of the defect. Next, the experimental finding of the cause of the defect, which is focused on the measurement of the pressures in the form of the casting, is devoted to it.
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