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Effect of material thickness on the width and properties of the heat-affected zone
Horák, Tomáš ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
Thess deals with the welding of high-strength steel by the MAG method and the evaluation of structural and dimensional changes depending on the thickness of the material. CREUSABRO 4800 steel was chosen using MEGAFILL 742 M additive material. A weld was created with welding parameters of 130 A, 20.7 V and a feed speed of 35 cm/min with a swing of 7 m, on steel with a thickness of 3, 6, 10 mm. Subsequently, a weld was made on samples with a thickness of 10 mm with welding parameters of 300 A, 28.8 V, 35 cm/min with a swing of 7 mm, while one of the samples was preheated to the recommended temperature. The resulting macro structure, micro images and the thermally affected area were evaluated.
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Snow chains manufacturing
Bořek, Pavel ; Kubíček, Jaroslav (referee) ; Císařová, Michaela (advisor)
This thesis is aimed at investigating the snow chain manufacturing process with a closer focus on the problematic spot related to the heat affected zone, weld and base metal. In the theoretical part, the issue of resistance welding and the metallurgical processes involved in the formation of a resistance weld are described for a better understanding of the nuances in the practical part where a structural analysis of the weld area in terms of microstructure, macrostructure and hardness is carried out. For this part, chain samples after welding, carburizing, quenching, tempering and zinc electroplating are used.
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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.
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Electron beam welding technology
Skalka, Jan ; Vaněk, Mojmír (referee) ; Richter, Tomáš (advisor)
The bachelor thesis is devoted to analysis of electron beam welding technology. It is unconventional method of welding characterized by high quality weld and narrow heat-affected zone of welded parts. This technology, due to its development and qualities, has found its application in many industries, primarily in aviation and astronautics. The vacuum is limiting feature of this method and it is necessary for electron beam welding. However, even in this area, the development of new technologies have not stopped and generates concrete solutions to those problems. The thesis is also focused on elektron beam welding of rotary parts in the piece and serial production.
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Study of cutting defects in flame cutting of limit thickness of carbon steel by fiber laser
Králík, Petr ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
This thesis deals with research of cutting defects at laser cutting of 15 mm thick carbon steel by Bystronic fiber laser with emphasis on wide cutting gap, which causes enlargement of wide of cutting gap and deterioration of roughness of cutting edge and increase of creation fo heat. The introduction describes the main types of lasers used for cutting sheet of metal and compare their advantages and disadvantages. Also described is a cutting process and its parameters, and also the possible cutting defects. An experiment was conducted on steels S355MC and S235JR and cutting defects were analyzed in relation to the set of cutting parameters. Next part determines the extent of the recommended parameters that should be chosen for specific cutting conditions and is balanced recommendations regarding the choice of material to be cut, and technological adaptations parts. In the last part is measured roughness of a wide cutting gap, the width of the heat affected zone and micro-hardness of the material.
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Comparison of GMAW and Plasma Welding
Nejedlý, Tomáš ; Mrňa, Libor (referee) ; Daněk, Ladislav (advisor)
Developed thesis compares MAG welding and plasma welding, with the same input parameters. Based on the literature was reviewed weldability and welding of both methods. It was experimentally for both technologies specifically designed heat input, evaluation and macrostructure of the weld dilution, the dimensions of the heat affected zone and finally test the hardness in the transverse direction Vickers.
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Comparison of the thermal influence by TIG method
Pavlas, Jan ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The presented bachelor thesis deals with arc welding of stainless steels by welding method TIG. It compares the influence of pulse and DC current on the welded component. Introduction analyzes the influence of arc welding on metallic materials, heat introduced into the weld and the heat affected area. Two experiments on S235JR and 1.4301 steel were performed to verify theoretical assumptions. The effects of current on the material were evaluated using the analysis of the tests and the calculation and the conclusions were made. Finally I made recommendations for practice and possible further research on the issue.
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Optimalization of plasma cutting parameters.
Vacula, Jakub ; Mrňa, Libor (referee) ; Daněk, Ladislav (advisor)
VACULA Jakub: Optimization of plasma cutting parameters Diploma thesis of the attendance engineer´s study – Mechanical Engineering, specialization Machinery Technology. Academic year 2008/2009. Faculty of Mechanical Engineering of University of Technology in Brno, Institute of the Manufacturing Technology. The Diploma thesis is concerned with the thermal division of a material, concretely by the plasma cutting. It monitors the operational parameters influence of this process to the result quality of cut and the purpose is to optimize these parameters from the qualitative standpoint. The experiment was executed at the plasma cutting equipment Fine Focus 800 of the company KJELLBERG with the utilization of the material S 690 QL. On the base of the literary study of the thermal division of the materials problems it was also described the comparison of the plasma cutting with the method of the division of materials by the oxygen, both from the point of view of the quality, and from the economical point of view.
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Resistance spot welding
Kosinka, Jakub ; Kandus, Bohumil (referee) ; Daněk, Ladislav (advisor)
The project describes the principle of resistance spot welding and sets the parameters which the quality of the weld nugget depends on. Moreover, it compares the macrostructure and mechanical properties of the spot welds made by soft or hard welding mode. In the experimental part, there is evaluating the strength of weld, precisely said cohesiveness weldments depending on the number of spot welds and their mutual position.
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The repair procedure of the press frame
Švarc, Lukáš ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
The diploma thesis is dealing with the repair procedure of the cracked ram of the press – machine parts made from gray cast iron by casting. The ram is a part of the repaired forming press LET 160. The presented work contains an overview and analysis of the technologies of repair of cast iron by welding. On the basis of the theoretical part is designed the procedure of repairing. The aim of the experimental tests is selecting the most suitable additional materiál and verifying the proposed welding process. The welding method was selected by a low preheating manual metal arc. All the pWPS were prepared for the welding of all test specimens. Experimental samples were subjected to visual, macroscopic, microscopic analysis and hardness measurement. Based on the results of the experiments was suggested a welding repair procedure with a pWPS.
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