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Production of thinwall iron castings
Kryštůfek, Tomáš ; Kaňa, Václav (referee) ; Roučka, Jaromír (advisor)
This diploma thesis is focused on production and problems in production of thin-walled ductile iron castings, especially in the inoculation process. The focus is on the influence of elements on the structure and mechanical properties of ductile iron and as well as the influence of some elements, that are commonly used in inoculation alloys. Furthermore, the factors that affect the production technology are written, i.e., solidification rate, wall thickness, cooling rate, and factors used for affecting the thin-walled castings production, i.e., the use of insulating moulding compounds and increasing the graphite nodule count. At the end of the theoretical part, important production processes are analysed, namely inoculation and spheroidization. The experimental part is focused on influencing the structure and mechanical properties using several types of inoculants of different chemical compositions, whereas the tested thicknesses of the test plates are 3-, 5- and 8-mm. Hardness, tensile strength and ductility are evaluated on these plates. Finally, the volume of ferrite in the structure, shape and size of the graphite nodules were examined.
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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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Modification of graphitic cast irons and fading of the modification effect
Paták, Daniel ; Bořil, Petr (referee) ; Kaňa, Václav (advisor)
The thesis presents a literature research concerning the production of cast irons with globular graphite. Emphasis is on the clarification of the modification principle and the fading of modification effect. Within the scope of the thesis, an in-house experiment investigating the issue has been carried out with a description of the modification method itself and an evaluation of the decay of the modification effect.
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Surface quenching of ductile cast iron
Neduchal, Bronislav ; Roučka, Jaromír (referee) ; Záděra, Antonín (advisor)
This diploma thesis is focused on the surface hardening of cast irons with spheroidal graphite. The work describes a theoretical analysis of the structure and properties of cast irons and individual methods suitable for surface hardening. The practical part describes the production of cast iron castings with spheroidal graphite, on which the surface hardening is performed, tensile test, hardening of produced castings by induction and laser surface hardening, preparation of samples for measuring microhardness and metallographic analysis of metal structures.
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Optimation of inoculation process of ductile iron
Ulm, Daniel ; Pecina, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master‘s thesis deals in theoretical part with the casting classification, ductile iron casting, its inoculation and modification and quality evaluation using thermal analysis, image analysis and testing of mechanical properties. The aim of the practical part was to test the effects of preconditioning on the properties of ductile iron and to find out whether it is able to replace the current method of inoculation or to increase the mechanical properties of ductile iron castings. The state of the ductile iron was under control by spectral and thermal analysis. The mechanical properties and image analysis were checked on finished casting.
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Quality control of the iron castings in the foundry
Krvač, Matěj ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
This bachelor thesis deals with the properties of castings with ductile iron and gray iron. The theoretical part was focused on knowledge related to chemical composition, mechanical properties and monitoring of internal defects. In the experimental part, the structure is evaluated in non-etched and etched state. It compares with the chemical component and the mechanical properties with the literature. X-ray frames are monitored for internal defects. In conclusion, the results of the experiments are summarized and measures are proposed to improve the casting quality.
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Cast Iron producing in foundry Slévárna a modelárna Nové Ransko and their charakteristics
Matulová, Anna ; Lána, Ivo (referee) ; Věchet, Stanislav (advisor)
This bachelor thesis deals with cast iron producing in foundry Slévárna a modelárna Nové Ransko and their characteristics in the form of literary research. In the first part graphite cast iron and its distribution is characterized. Furthermore, grey cast iron and ductile cast iron are described in detail in terms of mechanical properties, structure, chemical composition, production, heat treatment and use, and austempered ductile iron is specified. Then specific graphite cast iron, which foundry Slévárna a modelárna Nové Ransko used for production of castings, is listed and described. In conclusion, these materials are evaluated and their advantages and disadvantages are assessed.
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Surface melting of graphitic cast iron for hard layer preparation and its optimization
Adam, Ondřej ; Matlák, Jiří (referee) ; Jan, Vít (advisor)
The aim of bachelor thesis is description of microstructures, which were created by surface melting of ductile iron by using electron beam technology. The first part of bibliographic search deals with carbon and its effect on iron. The second part is focused on the general knowledge about cast irons, especially on graphitic cast irons. The last part of bibliographic search deals with electron beam technology. The practical part presents a microstructures, which were created by surface melting. Temperature cycles of the different material areas are described based on microstructures. In the end of bachelor thesis, there are chosen remelted layer with the best parametres and surface melting technology is optimized.
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Assembling the Technological Process for a Part of the Gearbox
Hoffmann, Jiří ; Osička, Karel (referee) ; Kalivoda, Milan (advisor)
The aim of my bachelor´s thesis is to create a technological process for manufacturing a gear housing component.. The chief output of my work is developing a technological process with the selection of appropriate tools for machining the casting. The thesis also deals with generating NC program, techno - economic comparisons, the design of worholding devices and recommends solutions of other identified issues.
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Low Cycle and High Cycle Fatigue Properties of Austempered Ductile Iron
Zapletal, Josef ; Věchet, Stanislav (advisor)
The thesis is focused on assessment of fatigue behaviour of austempered ductile iron with nodular graphite. Optimal period of transformation was determined based on the best combination of stress and strain characteristics established by tensile test. Cyclic response and low-cycle fatigue life were studied under both stress-control and longitudinal strain-control mode at room temperature. For both modes, shapes of cyclic hardening curves are dependent on stress amplitude. Cyclic deformation curves (CDC) were fitted by power regression function. Results were compared with CDC established by multiple step test in both modes with verification of the influence of cyclic creep (high stress levels, stress-control mode). Experimental data of S-N curves are in agreement with the Manson-Coffin and the Basquin law. Fatigue and cyclic parameters were compared. Fatigue life time in high-cycle fatigue region was determined. Experimental data were fitted by suitable regression functions. Regression parameters and fatigue limit were established by means of each regression function. Experimental data in low- and high-cycle fatigue regions were used to construct S-N curve and to determine relevant parameters. Discontinuity of experimental data was not observed. Low-cycle fatigue behaviour was predicted. Approximation of tolerance bands was realized in high-cycle and both high and low cycle fatigue regions.
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