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Welding of aluminum alloys using high-power semiconductor laser
Mikeš, David ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
Thesis deals with the optimization of process parameters during laser welding of aluminum alloys 5000 series. The theoretical part describes the types of lasers and their applications in industry, further discusses the properties of aluminum alloys, laser welding theory and principles of monitoring and diagnostics of laser process. In the experimental part the samples were welded using a semiconductor laser. For those samples were evaluated mechanical properties, welded defects and structure depending on the process parameters. Using the photodetector was observed stability of laser process by sensing the plasma plume. The link between stability and the formation of structural defects in the weld joint was observed from the measurement results.
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Assessment of heterogeneous properties butt welds in laser welding and electron beam welding
Rozsypal, Oldřich ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
The project was developed within the engineering degree in engineering technology, and is focused in welding together of two different materials. Welds will be done on a high strength steel Domex 420 MC and deep drawing steel DC01 using laser welding, and will be compared with the method of electron beam welding. Part of this project is a scientific research describing the basic physical principles of both methods, different types of lasers, welding material properties and inspection of welds. In the experimental part was carried tensile test, macroscopic and microscopic examination. Finally, work is to evaluate the individual tests.
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Repairs of lattice parts of ion filtres at NPP
Kloboučník, Martin ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The thesis focuses on repair preparation of Ion Filters at nuclear power plants cleaning units. The thesis shortly describes cleaning units of primary and secondary circuit where Ion Filters and Ion Catchers are implemented. The thesis introduces summary of convenient method for welding of thin filtration plates from austenitic materials to collecting pipe including convenient technology for fabrication of narrow loop holes in filtration plates. The aim of thesis is to propose convenient execution of repair and manufacturing of spare parts after different kind of damage of filter internals. Part of the thesis is welded joints quality verification on the testing sample including result of provided test, its evaluation and Ion Filters repair economical evaluation as well.
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Weldig of the different type of steel by the Yb-YAG laser
Chlád, Luboš ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The master's thesis presents an experiment of welding of high strength steel Docol 1200 M and of steel DC01 by the fiber Yb-YAG laser. The experiment is based on testing welds which were made during the experiments. The lasers, laser technologies of welding, steels of higher strength, tailored blanks technology and testing of welds are described in the theoretical part. The practical part contains description and evaluation of tests of welds – transverse tension test, Vickers hardness test, Erichsen cupping test and macrostructure and microstructure test. The final evaluation results of the experiment are presented in the conclusion of the master's thesis.
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Welding of finegrain steel from range of DOMEX steel by YbYAG fiber laser.
Němeček, Tomáš ; Daněk, Ladislav (referee) ; Mrňa, Libor (advisor)
The project elaborated within the engineering studies of the branch Manufacturing technology presents an experiment of welding of high strength steel by fiber laser. The project includes a theoretical study, which deals with the welding material properties, principles and types of lasers and laser welding technology. The practical part contains a verification of the welding parameters according to the standard ČSN EN ISO 15614-11. The final evaluation results of the experiment at the close of the project are presented.
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Weldig of the different type of steel by the Yb-YAG laser.
Kopecký, Lukáš ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
Diploma theses is focused on welding experiment of maraging steel by use Yb-YAG laser. Experimet is based on testing of combination steel 11321 and maraging steel. Domex420MC, Domex720MC a QSE380. In theoretical part there are described laser technology of welding, weld defect, maraging steel and inspection of welded joints. In experimental part there are porposed test and made mechanical test of weld as transverse tensile test, bend tests, Erichsen cupping test, Vickers hardness test and makroscopic and microscopic examination of welds. In conclusion there are analysis of the experiment results.
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Trends of development LASER technology
Zlesák, Jakub ; Kalivoda, Milan (referee) ; Osička, Karel (advisor)
The basic acquaintance with laser technology principles. The consideration and evaluation of this technology present state in engineering. The possibilities of applying new knowledge and discoveries in this field for using in engineering. The estimation of laser technology development within further 5 years and consideration of this technology economical demands.
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Comparison of properties parameters of laser solid state
Bazalová, Lucie ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The bachelor thesis deals with the characteristics, properties, parameters and application areas of solid-state lasers. It provides the explanation of the principle of laser beam and the associated individual types of lasers. This is followed by a more detailed division of solid-state lasers and their individual applications. Among these applications, more space is devoted to laser welding, where the main objective is to design a laser welding facility for steel welding up to a thickness of 10 mm.
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Laser welding of steels
Křivan, Miloš ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The project elaborated within the bachelor‘s degree field of B-STI Mechanical Engineering is focused on the problems of laser welding of steels. The theoretical part of this project deals with lasers, methods of laser welding, effects of welding parameters on weld quality and the weldability of steels. In the practical part sheets that were made of S355J2G3 and S355J2C+N steels were butt welded. The aim of the practical part was a determination of such welding parameters as the welded joints meeting the quality requirements according to ČSN EN ISO 13919-1 standard and the hardness requirement less than 380 HV10 according to ČSN EN ISO 15614-11 standard. The tests of the macrostructure of the welded joints were conducted and assessed and the hardness of the welded joints was measured.
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