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Interaction Core - Melt by Casting of Cylinder Heads from Al Alloys in Semi-Permanent Moulds
Hlavsa, Petr ; Roučka, Jaromír (referee) ; Tegel, Michal (referee) ; Rusín, Karel (advisor)
This dissertation thesis deals with interactions on the interface core - melt by casting of cylinder heads from Al alloys in semi-permanent moulds and solves a specific problem with sticky sand after decoring of a diesel cylinder head casting. It describes in detail the process of core production using the Cold-Box method and process of casting using the progressive technology Rotacast. It theoretically analyses the reaction on the interface core-melt and presents a classification of surface defects by Al castings produced by gravity casting into semi-permanent moulds. It also states the results of technological tests of binders, core mixtures and cores (Cogas analysis). By solution of a problem with sticky sand in intake and exhaust ports of diesel cylinder head casting is used methodology for problem solving DMAIC. All experimental tests are solved in laboratory and production conditions of an international company dealing with casting of cylinder heads from Al alloys in semi-permanent moulds.
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Manufacture and properties of SiMo cast iron
Abramova, Elizaveta ; Král, Vojtěch (referee) ; Roučka, Jaromír (advisor)
While using iron castings behind temperature of 500 oC namely at cyclic heat straining, degradation of structure and breaching iron castings. For this purpose introduce cast iron with content of Si and Mo. Focusing on improvement of SiMo51 for increased high-temmperature corrosion-and fatigue life in exhaust-gas temperatures up to 800 oC. Thesis set up survey types alloys, properties, and way of casting production.
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Heat treatment of aluminum casting alloys
Holátko, Petr ; Roučka, Jaromír (referee) ; Kaňa, Václav (advisor)
This bechelor thesis deals with the description of the heat treatment of aluminium casting alloys and is particularly focused on the frequent heat treatment, which is hardening. The first part describes the properties of aluminium alloys and are further explained the different kinds of heat treatment. The second part describes the experiment, which were cured, two different aluminium alloys. Here, the work focuses on change in hardness before and after hardening.
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Comparative performance of late stream inoculants in grey cast iron using thermal analysis
Chyla, Ondrej ; Bouška, Ondřej (referee) ; Roučka, Jaromír (advisor)
This diploma thesis in the theoretical part deals with classification of cast iron, problems of gray cast iron production, methods of inoculation and valuation of the gray iron quality by means of thermal analysis. The aim of practical part was to investigate effectiveness of inoculation of two different inoculants using thermal analysis. In terms of mechanical properties, hardness and ultimate tensile strength were measured. Metallographic specimen were evaluating by means of image analysis software.
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Analysis of non-metalic inclusions in motor heads castings and suggestion on their remove
Dratnal, Lukáš ; Lána, Ivo (referee) ; Roučka, Jaromír (advisor)
Improving the quality of metal castings for serial production of automotive industry, leading to improvements in the properties of casts and their lower costs. This publication analyzes the non-metallic inclusions contained in casts of heads of internal combustion engines, molded of Nemak Czech Republic, Ltd. Tackling includes analysis of size, shape, chemical composition and hardness of the specific non-metallic inclusions. The thesis describes the purity metal holding furnaces and proposals to eliminate inclusions from metal.
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Influence of exothermic sleaves on solidification of aluminium alloys
Zajíček, Roman ; Krutiš, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master’s thesis deals with the influence of the exothermic risers on the solidification of aluminum alloys. The work is divided into three parts. The first theoretical part describes the differences of properties of cast aluminum alloys compared to other based metals, especially iron alloys. It also describes the methodology of designing risers, composition of exothermic mixtures and finally gives an overview on the simulation programs on the market, their application in foundry practice and briefly explains how to define the material in the simulation program ProCAST. The second part describes the experimental measurement of the solidification time of aluminum alloy AlSi7Mg0,3 in the sand form with exothermic riser. The final section describes the simulation of experimental measurements. Further with help of simulation software it is tried to find the general principles that have an influence on feed module rate of exothermic riser.
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Influence of modification and inoculation on structure and mechanical properties of aluminium alloys
Janošťák, Jan ; Lána, Ivo (referee) ; Roučka, Jaromír (advisor)
This thesis examines the influence of inoculation and modification on the internal structure and properties of aluminium-silicon alloys. The effect of inoculation by titanium and boron and modification by sodium and strontium is investigated in experimental part of the thesis. All these metallurgical interventions in the melt are tested on three types of hypoeutectic Al-Si alloys (AlSi10Mg(a), AlSi8Cu3, AlSi7Mg0,3). The experiment was carried out in cooperation with the foundry of non-ferrous metals, Aluminium Group, a.s. in Sloup.
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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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