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Influence of degassing parameters on quality of Al castings
Jeřábek, Petr ; Horenský, Jiří (referee) ; Vašťák, Patrik (advisor)
This master’s thesis is focused on optimalization of degassing parameters in the foundry plant and effect of these parameters on mechanical properties of Al-Si alloys. In practical part is used factorial experiment to research effect of degassing parameters on mechanical properties and dichte index. After optimalization the new process is validated by comparing with the previous one. This experiment was taken on AlSi7Mg0,6 alloy in foundry plant MESIT foundry, a.s.
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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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Decarburisation and degassing of high-alloyed Cr steels under vacuum
Ertelt, Tomáš ; Pernica, Vítězslav (referee) ; Záděra, Antonín (advisor)
The work deals with the investigation of the effects of vacuum degassing and decarburization in high alloyed stainless steel. The reason for this is to increase corrosion resistance and mechanical properties. The theoretical part is devoted to the analysis of options to reduce carbon, nitrogen, hydrogen and manganese at atmospheric pressure and in vacuum. In experimental part there is the description of melting, calculation of conditions facilitating reduction of oxide inclusions as a function of the gas pressure in the furnace and the evaluation of the influence of vacuum on the content reduction of carbon, nitrogen and manganese.
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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.
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Optimization of metallurgical processes in aluminum alloys foundry
Halaška, Jan ; Lána, Ivo (referee) ; Kaňa, Václav (advisor)
Diploma thesis examines the influence of the preparation and metallurgical treatment on the mechanical properties and structure of aluminium alloys Al-Si. The experimental part was carried out at MSR Engines s.r.o. This part describes the current (sodium modification) and newly proposed (strontium modification) state of preparation and metallurgical processing of melt. There is state the course of experimental melting processes, testing of samples, evaluation of tests and observation of the impact of individual modifiers on the structure.
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Degassing of small amounts of aluminum alloy melt
Spáčil, Ivo ; Záděra, Antonín (referee) ; Kaňa, Václav (advisor)
The 40 kg melt was degassed by two methods: Immersion of a degassing tablet in a melt by an immersion bell and an argon degassing through a lance with a porous plug. Up-gassing tablets were also used during the experiment. The method of double weighing was used for evaluation. No technically significant degassing was achieved using degassing tablets. After degassing with tablets was observed a decrease in DI (Dichte Index) value with increasing residence time. Excessive dosing of the tablet does not ensure a higher degassing effect, it only ensures a higher turbulence of the reaction. Preheating the degassing tablets before use does not affect degassing. By preheating the up-gassing tablets, their reactivity is reduced. Two immersion bells with different proportions were tested. The bells do not ensure a homogeneous dispersion of bubbles in the melt. By argon degassing through the porous plug, the melt was degassed to a value DI = 1,87 %. The consumption of argon for degassing smaller amounts of melt is higher than for degassing larger amounts of melt. Argon refining is more efficient than using tablets.
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Secondary metallurgy in foundries
Klika, Jiří ; Šenberger, Jaroslav (referee) ; Pernica, Vítězslav (advisor)
The aim of this bachelor thesis is to write a literary research about various methods of secondary metallurgy. In the thesis is described principle of methods and its advantages and disadvantages after installation in the manufactory, especially principle of steelmaking methods. It mainly concerns advantages of secondary metallurgy as degassing, decarburisation, desulphurisation and chemical or heat homogenization of liquid metal in the ladle.
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Micropurity of steel manufactured in vacuum induction furnaces
Hořínek, Jakub ; Myška, Martin (referee) ; Záděra, Antonín (advisor)
During the production of steel, a certain proportion of non-metallic inclusions always arises, which significantly affects its final properties. The theoretical part of this thesis focuses on the effects of these impurities on the properties of steel and on ways to reduce their total content in steel. In the experimental part, the effect of vacuum melting, with casting in air, on the final micropurity of stainless steel was investigated. The results showed that the vacuum method was very effective as there was a significant reduction of the oxide inclusions content and oxygen content in the steel. Then, a part of the material from the first melting was remelted and the effect of repeated vacuum remelting of the material with casting in vacuum was investigated. The analysis showed a significant reduction in nitrogen content but the oxygen content remained almost the same.
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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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Micropurity of steel manufactured in vacuum induction furnaces
Hořínek, Jakub ; Myška, Martin (referee) ; Záděra, Antonín (advisor)
During the production of steel, a certain proportion of non-metallic inclusions always arises, which significantly affects its final properties. The theoretical part of this thesis focuses on the effects of these impurities on the properties of steel and on ways to reduce their total content in steel. In the experimental part, the effect of vacuum melting, with casting in air, on the final micropurity of stainless steel was investigated. The results showed that the vacuum method was very effective as there was a significant reduction of the oxide inclusions content and oxygen content in the steel. Then, a part of the material from the first melting was remelted and the effect of repeated vacuum remelting of the material with casting in vacuum was investigated. The analysis showed a significant reduction in nitrogen content but the oxygen content remained almost the same.
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