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Utilization of laser welding methods for fixation of electrotechnical sheet bundles
Adam, Tomáš ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
Thesis deals with individual technologies of packaging stator sheets and their use in practice. The greatest emphasis is placed on welding technologies, especially on the differences between the individual methods. The experimental part of the thesis is focused on finding suitable parameters for welding the stator package using a laser with a special wobling head. The samples were evaluated in terms of penetration depth, the number of defects, especially pores and grain coarsening.
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Accelerate handling strength in 2K PUR adhesives
Slatinská, Jana ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
This paper is devoted to accelerating the time to obtain the handling strength of two-component polyurethane adhesive, which was newly purchased by the company Magna Exterios (Bohemia) and had to be tested. In order to speed up the analysis of the problem, methods of IR emitters and temperature chambers were selected to be compared with curing using only the ambient atmosphere. In the second part of this paper, the maximum strength of the bond which withstand the test without damage was measured. The results show that the method of accelerating curing process using an IR emitter is the fastest, but the economic side of things must be taken into account, because it is also the most expensive option of acceleration. The temperature chamber is almost twice as slower, but cheaper. At the end of the thesis, the economic efficiency of the new adhesive line solution is evaluated and how much money can be ideally saved.
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Welding thin-walled pipes made of stainless steels
Naď, Tomáš ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The bachelor's thesis deals with technology of welding of thin-walled stainless steel pipes and the analysis of weldability of stainless steels. The theoretical part provides a basic description of the material's weldability and the basic defects in welding, the characteristics of stainless steels, their division, marking, alloying and a general overview of their weldability. The experimental part describes selected welding technologies used for the production of thin-walled stainless steel pipes (LBW, PAW, HFIW). Finally, the technology used to weld the presented samples of thin-walled pipes is ascertained and the macrostructure of the weld are compared.
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Welding the frame of the tandem bicycle
Rajm, Vojtěch ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
In the first part of thesis were compared frames of two different bicycles and according to this comparison was designed a geometry of tandem bicycle. In a next part were described the most common materials in cycling industry and theirs advantages and disadvantages. According to the comparison, the steel EN 25CrMo was considered as the most suitable material for its low prize and high strength. After that is described weldability of steels and types of cracks which are one of the most casual defects in welded materials. In another part of thesis are theoretically described kinds of suitable welding methods for bicycle frames. As the most suitable are methods in shielding gases MIG/MAG and TIG. As the best method was chose TIG welding. In a practical part of thesis are compared these methods experimentally. Tubes from selected material were welded by MAG and TIG. The TIG welding proved again as better because of deeper and tough welds.
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A comparison of different types of epoxy adhesives
Mihulka, Jan ; Žák, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
This thesis is focused on a bonding technology. The first part describes the theory of the bonding and it is discussed the main areas of this technology. The experimental part deals with the comparison of four two-component epoxy adhesives in terms of shear strength. For the experiment it had been selected adhesives: Bison Epoxy Universal, Pattex Repair Epoxy Ultra Strong 5 min, Ergo 7430 and Letoxit LH 232. After performing the experiment, it was shown that Bison Epoxy Universal and Pattex Repair Epoxy Ultra Strong 5 min achieved the strengths stated in the datasheet. The strengths of Ergo 7430 and Letoxit LH 232 adhesives was lower than stated in their technological products, thefore, did not meet our expectations. The reason for not achieving the declared strength was probably poor dosing or insufficient mixing of ingredients.
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Orbital welding assembly welds in the Nuclear Power by the TIG method
Lukášek, Zdeněk ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
The Bachelor's thesis looks at the possibility of using orbital welding by the TIG method on mounting welds in JE Dukovany. In the opening section, we deal with the issue of weldability, primarily carbon steels. Furthermore, the work focuses on TIG welding technology, both in the manual and mechanised way it details, including the advantages and disadvantages of both variants. In the experimental section, five test samples of ferric-perlithic material pipes were welded. The samples were assembled to simulate possible combinations that occur during pipeline assembly. Non-destructive and destructive controls followed, verifying the quality and mechanical properties of the resulting weld joints. In conclusion, the results of the trials were assessed and evaluated.
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Repair TS tubes of the steam generator by manual welding
Zeman, Tomáš ; Mrňa, Libor (referee) ; Kubíček, Jaroslav (advisor)
This bachelor thesis deals with repair of heat exchange tubes of steam generator of Dukovany Nuclear Power Plant. Defects in the material of the collector of the steam generator were to such an extent that it was necessary to proceed with manual repair by workers inside the collector. A number of inspection welds, thorough training and preparation were performed to obtain the qualification of the repair. The repair was followed by a series of tests and trials, which ended in a satisfactory result and the equipment was put into operation.
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Dependence of the laser weld geometry on the bevel size
Man, Antonín ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
This work deals with laser welding technology. It explains in more detail advantages and disadvantages, applications and direction in which this relatively young technology develops. The main topic of this work is welding of martensitic stainless steel with carbon structural steel. Components of this type can be found, for example, in the power industry, specifically the stator part of a steam turbine. Part of this work is also an experiment that will explain the dependence of the geometric dimensions of the material to be welded on the quality of the weld. The welded test specimens were subsequently tested by both the non-destructive and destructive methods. It can be stated from the results, that the size of the bevel does not affect the quality of the weld, nor geometry.
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Manual versus orbital GTAW piping welding
Hofbauer, Jan ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
In thesis are compared options of stainless steel piping welding, orbital and manual version of method GTAW and GMAW. At the beginning, these methods are described theoretically and after that there are described materials used for fabrication two test welds on austenitic steel piping of diameter 168 mm. The first weld was made by orbital method GTAW, the second one by manual method GMAW. Next, these two welds are compared based on defects, welding parameters and width of heat affected area. The conclusion is that both welds are defect-free and because of economical aspects is better to use orbital GMAW method for this diameter of piping.
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Electrophoresis coating
Holčapek, Jiří ; Kubíček, Jaroslav (referee) ; Žák, Ladislav (advisor)
This bachelor is based on a study of electrophoresis coating and corosion. The first part contains information about corrosion of metal and the importance of protecting metal parts. Then it deals with the technology of electrophoresis coating and technological process of creating electrophoresis coating. Finally, new trends in the field of electrophoresis coating are presented.
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