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Structure and properties of high silicon ductile iron
Paták, Daniel ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
The diploma thesis was focused on the production of solid solution strengthened ductile iron. In the first part, research dealing with nucleation embryos and nucleation mechanisms of graphite was developed. Furthermore, the mechanical properties of high silicon ductile irons, their tendency to form chunky graphite and its effect on mechanical properties were described. In the experimental part, 3 melts with 4; 4.5 and 4.1% Si content were cast. Tensile tests, metallographic samples and numerical simulations were performed to compare the mechanical properties, microstructure and chunky graphite appearance as a function of solidification time and silicon content.
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Shrinkage prediction of graphitic cast iron
Blažek, Petr ; Kaňa, Václav (referee) ; Krutiš, Vladimír (advisor)
The thesis deals with the shrinakage prediction of graphitic cast iron. In the theoretical part, volume changes and influences on graphene expansion are described in detail. Furthermore, pouring methods and simulation parameters related to schrinkage and pouring are broken down in the work. In the practical part, thermophysical data and metallurgical quality of the metal are optimized in the simulation. For the specified casting, the risers were designed according to theoretical methods and the simulation optimization module. Using optimized risers, it was possible to save the volume of metal per raw casting by about 25 %. For castings from the soft bentonite mold and from the mold from the GEOPOL® (a self hardening mixture), the volume was measured using a 3D scan. When they were compared, an uneven increase in the volume of the bentonite mould casting was 1.2 %. The increase was due to the strain of the mold in the graphite expansion.
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Influence of the metallurgical quality of the aluminum alloy melt on the properties of investment castings
Urban, Antonín ; Krutiš, Vladimír (referee) ; Kaňa, Václav (advisor)
The thesis focuses on the influence of shell temperature, wall thickness, and metallurgical treatment of the melt on the mechanical properties and structure of the AlSi10Mg aluminum alloy processed using the investment casting technique. The experimental part was conducted in the school foundry. Prior to the experiment, a series of simulations were performed to verify the feasibility of the experiment. The thesis describes the experimental design and conditions under which the experiment was conducted. Furthermore, it presents the evaluation of mechanical properties based on wall thickness, shell temperature, and modification. In the conclusion of the thesis, the effect of strontium modification is assessed with respect to wall thickness and shell temperature during casting, using micrographs from metallographic samples.
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Improving the internal quality of aluminum alloy castings by the optimization of foundry technology
Mátl, Vojtěch ; Krutiš, Vladimír (referee) ; Kaňa, Václav (advisor)
This master’s thesis deals with the topic of improving the internal quality of aluminium alloy castings using foundry technology optimization. Theoretical part of this thesis consists of five chapters. These chapters deal with topics of internal defects in castings, solidification of aluminium alloys, numerical simulations in foundry, feeding and use of chills. The second part of this thesis is experimental. It focuses on defect analysis of investigated castings, casting technology simulation and suggestions for its improvement, with consideration for liquid metal utilization.
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Influence of Mn and Cu on the structure and mechanical properties of cast iron
Musil, Ivo ; Pernica, Vítězslav (referee) ; Kaňa, Václav (advisor)
This bachelor’s diploma thesis deals with the influence of various factors, especially the chemical composition, on the structure and properties of graphitic cast irons. In the practical part, a planned experiment verifying the influence of manganese and copper on the mechanical properties and structure of graphitic cast irons is carried out, in which samples of cast iron with flake graphite alloyed with different manganese and copper contents are cast, the resulting hardness is measured and their structured is examined.
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Color metallography of foundry alloys
Nekuda, Pavel ; Záděra, Antonín (referee) ; Kaňa, Václav (advisor)
The theoretical part of the diploma thesis deals with the preparation and application of the most common color etchants and in the practical part, the applicability of selected reagents is tested. The obtained results are compared with the findings obtained from previous research works. Attention was mainly focused on etching samples of alloyed cast irons with Beraha's I, Beraha-Martensite and Beraha's CdS reagents in order to find the optimal method of color etching of austempered ductile iron. These samples differed in their chemical composition and wall thickness of the initial Y-block. Image analysis was also performed, where the sizes of the individual color areas, obtained by the Beraha's I reagent, were determined on the microstructures. The practical part of the thesis also deals with the application of Weck's reagent on two samples of AlSi7Mg silumin, while only one of them was heat treated.
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Production of castings from Cu-Ni based alloys
Kelbl, Michal ; Kaňa, Václav (referee) ; Záděra, Antonín (advisor)
This master thesis is focused on melting of Cu-Ni based alloys and production of castings from these alloys. The theoretical part includes introduction of Cu-Ni based alloys and their properties and application. At the end of this part is production foundry technology of Cu-Ni alloys described. In the practical part two proposed melt controls for cupronickel (Cu-Ni) and for monel (Ni-Cu) have been performed. From these melts trial castings, castings of blades and bearings have been produced. The trial casting and the casting of bearing have been produced by using sand moulds and the casting of blade by using ceramic shell. According to internall quality of produced castings the performed melt controls have been evaluated. In addition to the internal quality of the castings, the chemical composition, microstructure and mechanical properties were evaluated.
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Production of castings from aluminum alloy Unifont 90
Chvátal, Pavel ; Lána, Ivo (referee) ; Kaňa, Václav (advisor)
The diploma project deals with the aluminum foundry alloy Unifont-90. The aim of the project was to observe the effect of different pouring temperature and wall thickness of the casting on the mechanical properties and microstructure of the material. The theoretical part of the project describes selected properties of aluminum foundry alloys and foundry processes used in their casting. In the experimental part, measurements of mechanical properties and microstructure of the material of the investigated Unifont-90 alloy took place.
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