|
|
Studying the effect of the gap on the properties of laser butt welds
Holub, Matyáš ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
This thesis studies the impact of gaps on the properties of laser butt weld performed. For experiment was chosen DC01 ordinary steel and stainless steel X5CrNi18-10 (1.4301) with different thicknesses. The welding parameters depending on the gap between the welded plates remain constant. In the experimental part of the samples were welded using the Yb:YAG laser and compared to the tensile test, macrostructure, microstructure and Vickers hardness. At the end of the thesis are drawn experimental results.
|
|
|
Study of properties of laser welds of Hardox 450 material using arc preheating
Debs, Martin ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
In this thesis is studied the influence of arc TIG preheating during laser welding of 2 mm Hardox 450 material sheets. This material achieves its good mechanical properties by processes of heat treatment. That causes problems during welding because of heat degradation. Experimental sheets were welded within various configurations of welding parameters and positions of TIG nozzle. Testing specimens were cut out by laser and were used for tension testing, Vickers hardness testing and metallographical testing (macro and microstructure). The results of using the second heat source are: wider heat affected zone, smoother transitions among its zones, reduction of toughness and hardness, finer grain structure and occurring ferritic microstructure. This hybrid technology, combination of laser welding and TIG preheating, is very productive creating joints with greatly good quality. The thesis also contains a comparison with common MAG welding method.
|
|
|
Influence of shielding gas on weld properties of conductive laser welding of sheet from carbon steel
Kotrík, Marcel ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
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.
|
|
|
Thickness of sheet and hardness of welded joins
Valášek, Daniel ; IAE, Michal Loskot, IWE, (referee) ; Molliková, Eva (advisor)
Theme of this bachelor’s thesis is to determine the effect of material thickness, laser beam power and the material itself on hardness of the weld joint created by laser welding of construction steels. In addition to description of welding technology, this thesis also includes description of the undertaken experiment and its results which include photographs of microstructure from all weld joint zones and photograph evaluation.
|
|
|
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.
|
|
|
Visual inspection of transparent products
Matus, Gabriel ; Horák, Karel (referee) ; Honec, Peter (advisor)
This project deals with the optical control of welding glass blank. The blank consists two small parts of made of special glass. This blank is an essential part of the measuring device density of oxygen. Measuring device algorithm is based on paramagnetic properties of oxygen. It is a small and precise piece of the whole mechanism therefore the precision and perfection made strict criteria. For checking compliance with those criteria, developed a computer program written in C# programming language. Its task is to rule on perfection produced parts. It also serves to back up data on individual production units.
|
|
|
Laser welding of plastics
Nováková, Eliška ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The bachelor presents a brief characteristics of thermoplastics welding methods followed by a more detailed description of laser welding of thermoplastics, i.e. laser description, division and types. Then, conditions and parameters of welding are defined. The experimental part is focused namely on visual welding tests on a test sample. The sample consists of two types of material – pure polymethyl methacrylate and black polycarbonate – which are used in car headlamp production. For welding, a diode laser designed for thermoplastics welding was used. The main target of inspection were flaws that were visible on macroscopically enlarged images. The tested welds mostly showed porosity and air bubbles. Finally, an evaluation of the experiment is conducted.
|
|
|
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.
|
|
| |
|
|
Modification of a laser welding system for welding materials releasing excessive amounts of fumes
Kohout, Jaroslav ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
The thesis deals with the implementation of a suction system for laser welding. The specific product is grate used for outdoor drainage. The original GMAW production technology is to be replaced by a laser. During the welding of S235JR steel, a significant development of exhaust gases was observed, which subsequently made the actual process impossible. Practical experiments were performed and evaluated using tensile testing and metallographic cut. Based on the results, the optimal position of the suction nozzle and welding parameters were recommended. The obtained values were re-verified by experiment. Furthermore, a suitable extraction device was proposed and an economic evaluation was performed.
|
guest ::
