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Influence of sand size of core mixtures on surface quality of cast iron castings
Brůža, František ; Krutiš, Vladimír (referee) ; Záděra, Antonín (advisor)
The diploma project deals with the mechanisms of burn-on casting defects on castings made of spheroidal graphite cast iron. It discusses the elimination of their occurrence in the conditions of the German foundry MAT Ueckermünde by changing the granulometry of the core sand. Subsequently, the thesis deals with the influence of this change on the greensand. Furthermore, the thesis compares three refractory coatings supplied by the foundry. The coatings are compared both by laboratory measurements and by experimental tests during casting in conditions simulating the operation of this foundry. Finally, the individual tests are evaluated, including the effect of the individual measures in the case of their use in MAT Ueckermünde.
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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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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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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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Mechanical Properties of the Casting from Ductile Iron
Semrád, Lukáš ; Andres, Jan (referee) ; Věchet, Stanislav (advisor)
Graduation theses consist of two parts. The first one, theoretical is focused on piece of knowledge regarding nodular iron history, its mechanical properties, chemistry, production and heat treatment. Theoretical part also includes information relating to graphite and white irons that relate closely with nodular iron. Important chapter is description of isothermal refining which is the subject of these theses. The second, experimental part is focused on isothermal refining of nodular iron casting. Description of the casting introduces this section, material specification, production and application. Following chapters describe preliminary conditions for isothermal refining that is applied on every single specimen made of the casting. These specimens have been tested mechanically. Optimal procedure of isothermal refining is applied on whole the casting and characterized final mechanicals. Final mechanical properties after casting isothermal refining has been analyzed and confronted with literature.
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Application of Homogenization Annealing to Suppress Silicon and Nickel Segregation in Ductile Iron
Pavloušková, Zina ; Zemčík, Ladislav (referee) ; Vřešťál, Jan (referee) ; Švejcar, Jiří (advisor)
This doctoral thesis deals with the comparison of different methods of alloying elements’ concentration measurement based on energy dispersive spectroscopy and also with the suitability of particular methods of quantitative assessment of heterogeneity of the spheroidal graphite cast iron matrix. The segregation curves construction, distribution coefficient and heterogeneity index formulation is also discussed. The notion “normalized distribution coefficient” is introduced newly. The goal of the thesis, which is to be achieved by means of evaluation of large experimental data sets, is the evaluation of applicability of homogenization annealing of spheroidal graphite cast iron with the aim to eliminate segregation of silicon, and mainly nickel, as pearlite- and carbide-forming agent at the border of an eutectic cell. The result is an optimized homogenization annealing schedule maximizing the suppression of silicon and nickel segregation while taking into account the minimization of financial expenses and risk of grain coarsening.
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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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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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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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