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Technology of high pressure die-castings and influences having effect on their quality
Štipl, Pavel ; Prášil, Tomáš (referee) ; Roučka, Jaromír (advisor)
This diploma thesis deals with the technology of high pressure die casting and especially influences having effect on their final quality. The aim of this thesis is to design the measures to convert casting of the cylinder for chainsaw into the serial production. The thesis contains a description of the production of castings by technology of high pressure die casting, theoretical analysis of the factors with effects on their final quality and practical description of the conversion casting of cylinder for chainsaw into the serial production. The problem of converting to serial production has been solved by several samplings and final test series. Part of each sampling is analysis of defects and design of measures leading to elimination or at least minimization of such defects. On the basis of the production process has been successfully optimized and casting of the cylinder for chainsaw was successfully converted into the serial production. The results of this work also allowed for a smooth conversion into the serial production of another type of cylinder, manufactured by company MOTOR JIKOV.
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Optimization of die casting technology for the casting of vacuum pump
Krňávek, Štěpán ; Kolmačka, Marek (referee) ; Roučka, Jaromír (advisor)
Diploma thesis deals with optimization of technological process casting a die cast, which is part of vacuum pump. The die cast is made from alloy AlSi9Cu3(Fe) in foundry KOVOLIT, a. s. There is a problem with inner defects at this cast. Solution of this thesis is to suggest suitable actions to minimize of incidence the defects in the cast. According to analysis of the defects in the cast these defects were classified as combination of shrinkages and gas holes. According to analysis causes of the defects are high temperature of die mould and closed air in die mould. As a result suitable actions were suggested – a change of the die mould tempering and a design adjustment of the cast. In case of implementing a new die mould in the manufacture a new gating system was designed. Suitability of the new gating system was assessed according to simulation of filling die cavity.
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Use of controlled gassing of Al-Si alloys during die casting
Jankes, Erik ; Kaňa, Václav (referee) ; Roučka, Jaromír (advisor)
This master thesis will cover the possibility of using directed gassing of Al-Si alloys in a high pressure die casting foundry. As a control gas, rotary degasser with gaseous 20 % H2 in N2 as a medium was used. Castings were casted via high pressure die casting machine. The aim of this research is to compare internal defect such as porosity or shrinkage of a casts made from degassed and control gassed melt.
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Optimization of macrostructure of nickel-based alloys castings
Šmíd, Michal ; Ňuksa, Petr (referee) ; Roučka, Jaromír (advisor)
This diploma thesis is focusing on possibilities of influencing casting’s structure of nickel superalloy Inconel 713LC by force effects caused by vibration and rotation during crystallization. In this research were cast three test castings of turbine wheels with different solidification conditions that have affected the size and distribution of the grains. The aim was to compare the different microstructure and macrostructure of castings and then compare the dependence of grain refinement on mechanical properties. Changes in the structure were analyzed by means of light and electron microscopy methods after the fracture of test bars.
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Controled crystallisation of aluminium alloys castings poured in shell moulds
Mašková, Lenka ; Střítecký, František (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis is to verify a possibility of controlling the crystallisation of aluminium alloys poured in shell moulds in order to achieve directional solidification. For this purpose, new cooling plant has been designed and fabricated. Several sample castings were produced under different initial conditions. Based on the evaluation of measured temperatures, a numerical simulation of heat transfer was created using the ProCAST software. Finally, the sample castings were sectioned into specimens that were, subsequently, metallographically polished and the evaluation of their structure with respect to the amount and types of defects was performed.
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Costs reduction in production of Al-alloy castings
Nováková, Lucie ; Lána, Ivo (referee) ; Roučka, Jaromír (advisor)
This thesis deals with solving the most serious internal defects in castings made of aluminum alloys which are cast in sand molds in Slévárna a modelárna Nové Ransko Ltd. The problem solving contains a description of the problematic castings with the investigation of the structure and phases and subsequent detailed analysis of their production. The Author of this thesis also examines the influence of Fe and Mn on a possible formation of the internal porosity with the help of test meltings with the evaluation of the internal structural change. The Author’s design solution is a close checking of chemical composition with regard to the ratio Mn / Fe present in the alloy, the purchase of Foundry Degassing Unit to reduce gassiness of melted metals and better control of gassiness with the help of the appropriate equipment for the density Dichte index.
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Solidification of castings by pouring into shell moulds in vakuum furnaces
Odložil, Jan ; Ňuksa, Petr (referee) ; Roučka, Jaromír (advisor)
Heat transfer during metal pouring and its solidification in the vacuum furnace have been investigated by experiments using model set of castings of different diameters and insulations. The pouring metal was Inconel 713LC alloy based on nickel. The found data have been used for optimization of the numerical simulation of the thermal regime during the both pouring and solidification phases of the process in vacuum. Numerical simulation of the alloy structure in individual castings has been made by the CAFE module of the ProCast software and obtained results compared with the real structure. The optimized boundary conditions can be used for simulation of real castings.
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Manufacturing of replica of Laurin-Klement engine
Krejčí, Kamil ; Zvěřina, Zdeněk (referee) ; Roučka, Jaromír (advisor)
The goal of the graduation thesis is building of a working replica of the motorcycle engine Laurin&Klement, type TB from 1902. The thesis focuses on the manufacturing of cast parts. The piece production of the engine has been based on extant original pieces, missing pieces have been manufactured according to period photographs and leaflets. This method can be applied for production of missing or damaged pieces of historical motorcycles‘ engines.
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