National Repository of Grey Literature 94 records found  previous11 - 20nextend  jump to record: Search took 0.00 seconds. 
Production of spacious thin wall castings from aluminium alloy
Meduna, Radek ; Talián, Viktor (referee) ; Roučka, Jaromír (advisor)
The diploma thesis deals with the production of spacious thin-walled castings of aluminum alloys with a good surface quality. During the casting process, different types of molding sands and aluminum alloys are used. The target of the diploma thesis is to evaluate the casting surface quality, to analyse the defects and to evaluate the results.
Influence of filters on running of metal flow
Makalouš, Jakub ; Veverka, Aleš (referee) ; Roučka, Jaromír (advisor)
This study deals with influence of filters on running of aluminum metal flow. The main objective was to describe hydraulic resistances of assorted filters and running of silting filters by inclusions. Theoretical part generally describes filtration process and also filtration from the point of view of aluminum alloys and the most important characteristics of each type of alumina inclusions. Experimental part deals with flow rate tests, influence of filters on gassiness of melt and metallographic analysis. It was find out, that filter GEPHAL made minimal hydraulic resistance, on the other hand ceramic foam filters type LD made the maximal hydraulic resistance. It is necessary to reduce filtration surface for study running of silting filters by inclusions. Metallographic analysis showed amorphous alumina film inclusions, spinell Al2O3.2MgO, sludge and carbide of silicon.
Influence of thermal treatment regime of Al-Si alloys on mechanical properties
Letovanec, Juraj ; Kolmačka, Marek (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis is influence of precipitation hardening regime, specifically quench rate, on mechanical properties of aluminium alloy A356 (AlSi7Mg0.3). Samples were after solution treatment quenched into water with different temperatures and age hardened. Tensile strength tests, hardness tests and microstructure observations were done after heat tretment.
Thermo-physical parameters of exo-sleeves and their application in simulation programmes
Zajíček, Roman ; Kuzma, Zbyněk (referee) ; Roučka, Jaromír (advisor)
Thesis discusses exothermic sleeves. The first chapter briefly described the defects can occur during solidification. Further, there are provided methods for removing these defects. The method is described in detail using risers with an emphasis on the exothermic sleeves and thermo-physical parameters characterizing these sleeves. It also describes the influence of these parameters on the accuracy of computer simulations. In the final part of the work is done measuring of the real casting, which is then simulated in the Quikcast.
The Al-Mg alloys in technical use
Hotař, Jan ; Střítecký, František (referee) ; Roučka, Jaromír (advisor)
Score casting alloys Al-Mg-type and their characteristics and usesing. Developing this kind of alloys with high strength and elongation, which are suitable for casting automobile casts.
Optimalisation of casting and solidification behaviour axial turbo wheels to achieve fine-grained structure in the castings
Matoušek, Roman ; Ňuksa, Petr (referee) ; Roučka, Jaromír (advisor)
The aim of this thesis is to investigate the influence of the structure of castings from the nickel superalloy Inconel 713 LC using rotation and cycling by casting table. The aim is to achieve a fine-grained structure and the best mechanical properties through varying the oscillation parameters during casting crystallization. Six castings of axial turbine wheel were initially casted for the purpose of this thesis. After evaluating their macrostructure, microstructure and mechanical properties, four additional axial turbine wheels were casted in order to validate the results.
Influence of repair welding by elevated temperatures on structure and hardeness of lamelar grafite iron castings
Procházka, Jan ; Bouška, Ondřej (referee) ; Roučka, Jaromír (advisor)
The master‘s thesis deals with the influence of the thermal cycle of welding with preheat on castings made of grey cast iron to change the hardness. The thesis deals with the classification of graphitic cast irons, their structure, properties and influences they have on the formation and transformation of the structure. Emphasis is placed on chemical composition and structure stability at elevated temperatures. The practical part deals with the investigation of the effects of casting repair on the decrease of hardness measured in the foundry Heunisch Brno.
Optimation of inoculation process of ductile iron
Ulm, Daniel ; Pecina, Vladimír (referee) ; Roučka, Jaromír (advisor)
The master‘s thesis deals in theoretical part with the casting classification, ductile iron casting, its inoculation and modification and quality evaluation using thermal analysis, image analysis and testing of mechanical properties. The aim of the practical part was to test the effects of preconditioning on the properties of ductile iron and to find out whether it is able to replace the current method of inoculation or to increase the mechanical properties of ductile iron castings. The state of the ductile iron was under control by spectral and thermal analysis. The mechanical properties and image analysis were checked on finished casting.
Influence of degasing on casting quality by high pressure casting
Míšek, Jakub ; Kolmačka, Marek (referee) ; Roučka, Jaromír (advisor)
This thesis examines the influence of the degassing process on hydrogen contend and on the quality of part casted by high pressure casting technologies. The type of defects occurring in the casting is analyzed based on macrostructure and microstructure observations. For the overall assessment is used the statistical observation of the evolution trend of scrapping during the experiment. The results show that shortening of the degassing time may affect the incidence of porosity defect.
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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