|
|
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.
|
|
|
Low Cycle and High Cycle Fatigue Properties of Austempered Ductile Iron
Zapletal, Josef ; Bokůvka, Otakar (referee) ; Kunz, Ludvík (referee) ; 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.
|
|
|
Production of Ductile Iron with Feritic Matrix
Blaha, Marek ; Šupálek, Milan (referee) ; Molliková, Eva (advisor)
This bachelor thesis deals with the properties and production of ductile cast iron with ferritic matrix. Theoretical part is focused on basic information about ductile iron, its chemistry, structure and mechanical properties. The production of ductile iron with ferritic matrix in JMA Hodonín Ltd is described in the next chapter of this thesis. In the experimental part the real cast is described together with its production technology and material. The practical part is concentrated on comparison of chemical composition, structure and mechanical properties of material of cast and keel blocks made of the same melt. Finally the results of experiments are summarized and the arrangements for improving conformity between material of cast and of keel block are suggested.
|
|
|
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.
|
|
|
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.
|
|
|
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.
|
|
|
The influence of cast iron inoculation with bizmut containing inoculant on structure and mechanical properties
Nyékyová, Dominika ; Navrátil, František (referee) ; Roučka, Jaromír (advisor)
The diploma thesis deals with the modification and inoculation of cast iron with spheroidal graphite, the influence of the chemical composition on the shape and size of the graphite nodules and ferrite/perlite ratio in the structure. The aim of the practical part was to determine the effect of inoculant containing bismuth (SMW 605) on microstructure and mechanical properties of ferritic ductile cast iron GJS 400-15. The dissolving time of mold inoculant was further investigated. The samples were subjected to a tensile test, Charpy impact test, hardness test and graphite morphology and ferrite/perlite examination using standard ČSN EN ISO 945-1.
|
|
|
Structure and mechanical properties of thin wall nodular iron castings
Chýlková, Adéla ; Mores, Antonín (referee) ; Roučka, Jaromír (advisor)
The purpose of this final thesis is experimental verification of the influence of graphitic inoculants containing different amounts of trace elements on the structure, mechanical properties and internal homogeneity of thin-walled ductile iron casting. This thesis describes the issue with casting of thin-walled ductile iron. Two melts of thin-walled test plates with thickenesses of 3-, 5- and 8 mm were done in experimental part. A total of six types of inoculations with different content of trace elements were tested. Subsequently, an X-ray irradiation analysis was performed on the samples and hardness, tensile strength and ductility were evaluated. Futhermore, the amount of graphite in structure, graphite shape, graphite size, nodularity, graphite nodule count and volume phases of ferrite and perlite in matrix were analysed in thin-walled ductile cast iron by computer-based image analyzer. Finally, the measurement data were processed into tables and charts and conclusions were formulated. An X-ray analysis proved, that all thin-walled test plates containned shrinkage porosity. Furthemore it was confirmed, that content of manganese in inoculant increases tensile strength and hardness. Also content of zirconium in inoculant increases graphite nodule count.
|
|
|
Structure and mechanical properties of thin wall nodular iron castings
Chýlková, Adéla ; Mores, Antonín (referee) ; Roučka, Jaromír (advisor)
The purpose of this final thesis is experimental verification of the influence of graphitic inoculants containing different amounts of trace elements on the structure, mechanical properties and internal homogeneity of thin-walled ductile iron casting. This thesis describes the issue with casting of thin-walled ductile iron. Two melts of thin-walled test plates with thickenesses of 3-, 5- and 8 mm were done in experimental part. A total of six types of inoculations with different content of trace elements were tested. Subsequently, an X-ray irradiation analysis was performed on the samples and hardness, tensile strength and ductility were evaluated. Futhermore, the amount of graphite in structure, graphite shape, graphite size, nodularity, graphite nodule count and volume phases of ferrite and perlite in matrix were analysed in thin-walled ductile cast iron by computer-based image analyzer. Finally, the measurement data were processed into tables and charts and conclusions were formulated. An X-ray analysis proved, that all thin-walled test plates containned shrinkage porosity. Furthemore it was confirmed, that content of manganese in inoculant increases tensile strength and hardness. Also content of zirconium in inoculant increases graphite nodule count.
|
|
|
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.
|
guest ::
