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Analýza CMT svarových spojů
Doležel, Radek
Thesis on Analysis CMT welded joints simply describes welding process and CMT welding methods. Individual chapters deal with the emerging defects in the weld-ed materials and inform readers with selected non-destructive methods. An important chapter is the CMT welding process at the selected three pairs of material CMT and CMT welding evaluate the advantages for heterogeneous materials (aluminium and steel).
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Kvalita svarových spojů
Pénz, Attila
The thesis may be divided into two parts, the theoretical and practical part. In the theoretical part of my thesis describe the permanent connection in engineering includes soldering, gluing, riveting and welding and further describe the building-up and weldability tests as part of the technological tests. In the practical part of my thesis describe what and how I was doing. How I progressed in the production of individual samples and testing. We can find there a description of the tensile test, graphical display each tensile test, measured and calculated values and evaluation of tests. Further describe the detection of microstructure and microhardness. Each photo of microstructure I worked to the table and commented what can we see on them. At microhardness we can read about the gist and execution of the test. Obtained values I compiled to the chart and commented. According to the hardness can recognize a structural component and phases. In conclusion is a summary of the measured values and evaluation.
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Vliv teploty na pevnost svařeného a lepeného spoje z materiálu Resysta®
Hrabovský, Štěpán
This master thesis shortly deals with properties and usage of the Resysta material. The main objective of this thesis is to determine a temperature influence on tensile strength of welded and glued joints made from the material Resysta, for an usage such as an outdoor furniture, temperature influence analysis of the joints and to present the results of the analysis obtained by measurements. Further objectives are: tensile strength experiment of material Resysta and to determine influence of placing the pieces in a desk in different directions. Results will serve as a basis for a specific firm; as a basis for deciding between technology of gluing and a technology of welding and also for input for a custom made single purpose machine made for welding of material Resysta. Tests were performed in exposure temperatures -30 °C, 20 °C and 60 °C. We will perform two tests; first test will focus on the tensile strength of glued and welded joints and second one will try to test of tensile strength of Resysta material. Experiments were conducted according to standards ČSN EN 205 and ISO 527-1 on the Instron 3365 testing machine. Laboratory tests showed that values of tensile strength were decreased while increasing the exposure temperature and this was consistent in every test performed. A statistical significance was also confirmed in work piece direction influence on a board. There were higher values of the tensile strength in longitudinal direction than in the transverse.
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Význam nedestruktivního zkoušení v oblasti hodnocení kvality svarů během procesu
Koucký, Miloslav
The diploma thesis The significance of nondestructive testing in the area of evaluation of the welds quality during the process is focused on the area of creating a material weld joint that cannot be disassembled. In the theoretical part the area of fusion welding, methods of fusion welding and defects of weld joints are analysed. Assessment of current practice of verification of the weld joint quality using nondestructive testing is analysed, too. In the experimental part of the diploma thesis progressive examination for assessing the weld joint quality is suggested from the view of making an expert as-sessment. The suggested method of evaluating the making of welds is also verified in an experimental way and the gained results of the performed measurement are compared with the existing method of determining the weld quality. In the final part of the diploma thesis economical assessment of the benefit of the suggested method and its incorporation into the qualification of an expert engineer is carried out.
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Analýza jakosti „Cold Metal Transfer“ svarů
Polák, Vojtěch
This diploma thesis is focused on overall research of the quality of joining steel and aluminum alloy using the CMT welding process. The theoretical part describes the principle and the technology of the welding system that allows joining dissimilar materials by an electric arc. Attention is also given to other modes such as CMT Advanced, CMT Pulse and CMT Advanced Pulse, which further improve the innovative process. These modifications include an efficient tandem method CMT Twin that uses two electric arcs in various combinations. The main aim of the experiment is assessment of the quality of created CMT joints. Individual tests are conducted to evaluate the corrosion resistance in an aggressive environment (salt fog). The testing subsequently evaluates mechanical properties by a destructive tensile test to determine the tensile strength. Part of the quality assessment is metallographic analysis including determining the elemental composition of the weld.
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Design modification and CFD simulation of the filling valve
Klíma, Štěpán ; Kohút, Jiří (referee) ; Klas, Roman (advisor)
This thesis deals with the design of a filling valve guide using a metal 3D printing method for application in a hydraulic press. The production of a filling valve guide using traditional forms of manufacturing in terms of labour, production, technology and time-challenging processes and the metal 3D printing method can help to overcome some of these challenges. The introduction of this paper is concerned with explaining the function of filling valves in the hydraulic press mechanism and a brief introduction to valve guide manufacturing technologies, including metal 3D printing technology. This is followed by an explanation of the new design in terms of the technology used. A strength analysis using FEA is then developed to determine the functionality of the valve guide and to optimise its shape. In this section, an iterative procedure was used to reduce the reduced stress in the ribs to 68 % of the reduced stress of the original design by changing the valve guide geometry. At the same time, a theoretical introduction to FEM is written, including an explanation of the non-linearities in FEM. This is followed by a comparison of the hydraulic losses due to oil flow through the original valve and the valve with the modified valve guide. Similar to the FEM chapter, a theoretical section is also written introducing CFD, mesh generation for CFD and turbulence models.
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Use of torch oscillation for butt and fillet weld welding of high-strength steels using the MAG method
Umlauf, Petr ; Slováček, Marek (referee) ; Kubíček, Jaroslav (advisor)
The first part of the thesis deals with the research on high-strength steels, their structural effects, weldability, metal transfer methods and common weld defects occurring in these steels. In the practical part, an experiment is designed to investigate the effect of weaving on butt and fillet welds, two specimens are prepared for each type of weld, one with weaving and the other control without weaving. The macrostructure, microstructure, hardness was evaluated on the specimens and tensile test was performed on the butt joint and a fracture test was performed on the fillet joint.
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