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Influence of shielding gas on weld properties of conductive laser welding of sheet from carbon steel
Kotrík, Marcel ; Sigmund, Marian (oponent) ; Mrňa, Libor (vedoucí práce)
In the thesis are analysed influences of three shield gases, based on literary pursuit. Compared was influence of the gas consisting of pure Ar, mixture Ar with 3vol.% CO2 and the mixture Ar with 18vol.% CO2 on mechanical properties of conduction laser welded blunt welds made from structural steel DC01 and S235JR with thickness 3mm and 2mm. Compared were strength properties of the welds in tension, weld hardness and hardness of the heat affected area under the low stress. Further was observed and compared stream of the gases during welding process and its influences on the appearance of the trial welds. On the metallographical cuts of the welds were evaluated mistakes and dimensions of the welds.
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The Imaging Of A Schock Wave Within A Supersoniclow-Pressure Gas Flow Using Opticalmethods
Bayer, Robert
Using Environmental Scanning Electron Microscope (ESEM), which uses high gas pressure within the specimen chamber instead of vacuum, allows us to study samples containing water, samples with high capacity and live biological samples. It is because of the lack of the need to freeze the sample to sublimate the water from it. However, the behavior of the pumped gas in low pressures is not well mapped to be the low-pressure gas flow simulations considered adequately precise for applying on ESEM. To increase the precision of simulations, it is possible to use optical methods for imaging the shock wave within the differentially pumped chamber because of its uniqueness.
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Influence of shielding gas on weld properties of conductive laser welding of sheet from carbon steel
Kotrík, Marcel ; Sigmund, Marian (oponent) ; Mrňa, Libor (vedoucí práce)
In the thesis are analysed influences of three shield gases, based on literary pursuit. Compared was influence of the gas consisting of pure Ar, mixture Ar with 3vol.% CO2 and the mixture Ar with 18vol.% CO2 on mechanical properties of conduction laser welded blunt welds made from structural steel DC01 and S235JR with thickness 3mm and 2mm. Compared were strength properties of the welds in tension, weld hardness and hardness of the heat affected area under the low stress. Further was observed and compared stream of the gases during welding process and its influences on the appearance of the trial welds. On the metallographical cuts of the welds were evaluated mistakes and dimensions of the welds.
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Využití šlírové metody pro zobrazení proudění v laserových technologiích
Mrňa, Libor ; Pavelka, Jan
Při laserovém svařování je důležitá znalost proudění plynu ochranné atmosféry kvůli stupni ochrany svarové lázně před atmosférou a kvůli interakci mezi plynem a obláčkem plazmatu vystupujícím z keyhole. Při laserovém dělení materiálu má proud plynu z trysky významný vliv na kvalitu výsledného řezu. V obou případech je šlírová metoda velmi užitečným nástrojem pro pochopení dynamiky proudění plynů. Bylo provedeno více experimentů, které objasnily proudění různých druhů plynu (argon, helium, dusík) a jejich dynamiku.
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