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Friction welding of part chains for forest machines
Houdek, Radim ; Mrňa, Libor (referee) ; Sigmund, Marian (advisor)
The bachelor's thesis is focused on the condition of the weldment of the part of the track, specifically the welding of the cube to the crossbar made of steel 50CrV4 and 27MnCrB5-2. The parts were welded by linear friction welding. The first part of the work is a literature search on the topic of linear friction welding and joined materials. The second part of the work presents the results of a closer examination of weldments. Their macrostructure, microstructure, microhardness were examined in all areas of the welded joint, the amount of residual austenite was determined by X-ray diffraction analysis, the materials were tested for chemical composition and the weldment was tested for breakage.
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Welding of 22MnB5 steel using Laser-TIG hybrid technology
Krejčí, Adam ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
This thesis deals with usage of hybrid technology Laser-TIG for welding of boron enhanced steel 22MnB5. This thesis evaluates the influence of preheating using technology of TIG arc welding to a weld quality in comparison with laser welds. In practical part of thesis there were 1,8 mm metal sheets of 22MnB5 welded. This metal sheet specimens were welded by using constant parameters of laser with varying parameters of TIG technology. There were 12 specimens of sheet metal created including 3 specimens using only laser and 9 specimens using Laser-TIG hybrid technology while varying magnitude of current (I=20 A, 40 A a 60 A). Welds created this way were evaluated by tensile test and strength limits compared. Then metalografic survey was carried out examining macro and microstructure. Results of metalografic survey were confronted with Vickers hardness test.
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Plasma overlay welding of cobalt alloy
Paleta, Petr ; Daněk, Ladislav (referee) ; Sigmund, Marian (advisor)
The thesis deals with plasma overlay welding of cobalt alloys. In the theoretical part of the thesis, suitable cobalt alloys for plasma overlay welding were described, out of which cobalt alloy Stellite 21, was chosen for overlay welding for particular part. Subsequently, the plasma overlay welding machine PPC 250 PTM and the torch PHP 250 S, used in the practical part, were described. In the practical part were debug overlay welding parameters and suggest the suitable overlay welding procedure for particular part.
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The problems of welding stainless steel 1.4541
Šmarda, Vladimír ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
This thesis focuses on austenitic steel welding in the upper part of a steam generator at the nuclear power station Dukovany, and the suitable technology when replacing this part. Part of this thesis is dedicated to the progressive methods TIG, such as the use of hot wire or orbital welding of pipe parts. The experiment in this thesis project tests the optimal parameters setup when welding while using a modified TIG method; a motor-fed hot wire with a welding source from EWM manufacturer was used in this project. Number of NDT tests, along with destructive tests including metallographic tests, demonstrated and verified that the methods, the additional materials and the way the experiment was carried out were chosen correctly and proved effective. These tests also included the hardness of the welding point and TOO locations. The experiment assessment part summarizes the experiment execution, describes the results of the tests, and recommends further continuation in the process toward WPQR
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Welding of deep-drawing steels with a protective layer by means of an oscillating laser beam
Holub, Kamil ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
This thesis deals with the topic of procedural parameters influence on the properties of welded joint in zinc-coated deep-drawing steels in laser welding with wobbling. First part of the thesis serves as an overview of laser welding technology, welding of steel with protective zinc layer and weld quality testing. Second part is dedicated to a proposal, process flow and evaluation of an experiment. Seven trial lap welding joints of DC04+ZE steel have been welded using different welding parameters. Specimens from these trial welds were used for metallurgical testing by macro-etch examination and for tensile strength break testing to get mechanical properties of welded joints.
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Welding parameters optimalization of robotic welding for car industry
Soprunenko, Valeriia ; Mrňa, Libor (referee) ; Sigmund, Marian (advisor)
Thesis deals with individual technology of new welding processes "specifically FRONIUS TPSi". The greatest emphasis is on welding technology, especially on the differences between the individual methods. The experimental part of the thesis is focused on finding suitable parameters for welding filled welds.Everythingwith respect to required welds quality welded by robotic welding. The samples were evaluated in terms of penetration depth, amount of heat introduced and the number of defects.
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Preparation and welding of the pressure aluminium pipes
Kocák, Tibor ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The project is an analysis of technology production of pressure pipes made of aluminum alloys. The basis is a literary study of TIG technology, aluminum heat-tretable and non-heat-treatable materials. The flange-material is EN AW 5083 and the pipe is made of EN AW 6005A. The design of the welding is compromise between the preparation, the cleaning of the welding edges and the weld metal backing strip. Weld was made in real production. Examined impacts are evaluated on the basis of destructive and non-destructive welding test methods. After heating process of weldment material exhibits better mechanical properties. Using the economical and technological evaluation were selected sutiable proces parameters. The result is a suitable weld of the pressure vessel. Further optimization is possible through automation and robotics.
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Welding of pipes made of CrMo steel
Matějek, Martin ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The aim of this diploma thesis is to compare mechanical properties of welded joints on tubes from 32x2 mm. Tubes are made from 25CrMo4 steel, which is used for production of racing kart chassis. The steel has a tensile strength of Rm = 800 MPa and up to 1200 MPa after refinement. For welding of samples are used technologies MAG and TIG.
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Optimization of the laser cutting technology of tubes with a square cross section
Podaný, Petr ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
The master thesis deals with the design and manufacture of tabbed joint in the profile with a square cross section using laser cutting. They examine their suitability and impact on the following MAG welding operation in terms of efficiency and accuracy. The theoretical part provides basic information about lasers used in industry and laser cutting methods. There is also a section dedicated to laser apparatus for tube cutting along with problematic about the laser cutting profiles. The experimental part describes the procedure of designing tabbed joint, making samples and measuring them. In the end, the individual samples are compared in terms of angular deflection after welding. The thesis also contains a technical-economic evaluation, where the costs of individual operations are quantified.
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Optimizing of robotized tandem welding with availing of laser cameras
Paťha, Vladimír ; Mrňa, Libor (referee) ; Sigmund, Marian (advisor)
This bachelor thesis deals with efficiency of new robotic welding cell in terms of speed, quality and productivity. This new robotic welding cell use a tandem welding torch and laser offline sensor for setting position of the seam. This new robotic welding cell use also dual axis rotator for better positioning and loss risk of weld metal flow. For all robotic welding cells is the same welding technology acc. international standard EN ISO 4063, welding method 138 and the same shielding gas M 21, acc. international standard EN ISO 14175, mixture of 82 % argon plus 18 % carbon dioxide.
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