National Repository of Grey Literature 70 records found  1 - 10nextend  jump to record: Search took 0.00 seconds. 
Robotic welding case of linear fluid motor produced from high-strength steel
Hejduk, Stanislav ; Slováček, Marek (referee) ; Sigmund, Marian (advisor)
The theses deals with the welding of high-strength steels S690 QL using the MAG method. The aim of the work was to conduct a feasibility study for welding VP steels. Welding took place in a robotic workplace. Welding parameters were calculated, and subsequently, a pWPS was created based on these parameters, according to which a test sample was welded. The welding was performed without preheating or post-weld heat treatment. The welded samples were then evaluated using non-destructive and destructive testing. No unacceptable surface defects were detected through non-destructive testing. Destructive testing verified the size of the heat-affected zone (HAZ), with the most significant influence observed in the cover layer, and a value of 2.5 mm was determined. The hardness test according to Vickers also yielded successful results, with the highest measured value being 377 HV0.2. The tensile test resulted in failure within the HAZ, but the mechanical properties were comparable to the base material. Therefore, the weld on the test sample was evaluated as successful.
Evaluation of the quality of laser cutting surfaces
Krejčiřík, Marek ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
As the title implies, the topic to be solved in this diploma thesis was describing and evaluating the CO2 and fiber laser cutting technologies and their comparison with plasma and oxygen cutting, described in the standard ČSN EN ISO 9013. Samples of IMEX 700 high-strength fine-grain steel with a yield strength of 690 MPa were used and subjected to a final quality assessment. The diploma thesis is divided into two parts – theoretical and experimental. The theoretical part is mainly focused on a laser. Among other things, the principle of plasma and oxygen cutting was discussed. The cutting edges of samples cut by these methods were analyzed and compared in an experiment. Last but not least, the surface roughness, material hardness, and their measurement methods were discussed in the theoretical part. The final cuts after laser, plasma, and oxygen cutting were evaluated and compared in the experimental part. The roughness of the individual cuts was compared, and measured values were classified into the relevant quality classes specified by the standard EN ISO 9013. The thermal influence of the cutting joint, the width of the thermally influenced area and the hardness history were further evaluated parameters. The obtained results were discussed and summarized in the conclusion. Studied technologies were compared. Based on the experiment, fiber laser cutting was determined as the best choice regarding quality and economics.
Welding of aluminum alloys with using SKS welding equipment
Šaloun, Jan ; Slováček, Marek (referee) ; Sigmund, Marian (advisor)
This thesis focuses on robotic MIG welding of aluminum alloys using welding processes from SKS Welding. The main task was to fine-tune the welding process to produce a weldment composed of profiles made of EN AW-6061 T6 alloy with a complicated cross-section connected by two fillet welds. Due to the limited number of profiles reserved for debugging, the welding process behavior was first tested on filled and overlap joints of 3 and 5 mm thick sheets made of EN AW-5754 H22 alloy with similar weldability to the alloy of the profiles. Both alloys could be welded using Argon 4.6 shielding gas and AlMg5 filler wire with a diameter of 1.2 mm. Fine-tuned KF-Pulse DP welding processes of sheets were used to initially set the welding parameters for the profiles. Variables were then gradually adjusted until acceptable visual and internal quality verified by metallographic cuts at the desired locations was achieved. A major challenge was to achieve the necessary penetration in areas where there were ribs. This requirement was achieved through a combination of different welding speeds, current values, and wire feed rates. Pores were reduced using the special Dual Pulse function.
Replacement of nickel alloy overlay by manganese alloy overlay
Hlobil, Albert ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The thesis is focused on the issue of tuning the welding process of the 18.8. Mn alloy using the method 152. The welded component is the cylindrical throat of a Venturi tube made of ASME SA-106 Grade C carbon steel. A series of welds were performed, which were qualitatively evaluated and compared. Metallographic sections were made, and the dilution, excess, and width of the heat-affected zone were determined. Evaluation of microstructure and microhardness were also performed. Based on the tests performed, suitable welding process parameters were used. For comparison, a test for chemical and salt mist corrosion was undertaken, where the corrosion resistance of the 18.8. Mn alloy weld was compared to Inconel 625 alloy.
The effect of aluminum age on welding and other technological processes
Hanáková, Anna ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with the investigation of changes in the properties of aluminium alloys with respect to the age of the material. Aluminium alloy EN AW 6060 of different ages was chosen as the tested material. The alloy was in form of shaped or flat extruded profiles provided by company Pars Komponenty, s.r.o. First, a theoretical basics about the properties and division of aluminium and its alloys were presented, their heat treatment and welding options were presented as well. The theoretical part concerning welding focuses mainly on the problems of welding aluminium alloys and defects of the welded joints. In connection with this issue, material tests of basic materials and welded joints are described as a tool for detecting defects and determining the mechanical and technological properties of the material. In the experimental part, the profiles were TIG welded. Next, hardness, tensile, bending and macroscopic tests were performed. The results were technically and economically evaluated.
Comparison of manual laser and TIG welding
Černý, Jan ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The diploma thesis deals with the comparison of TIG welding methods (141) and unconventional methods of manual laser welding (51) of thin sheets of stainless steel X5CrNi 18-10. The goal of the thesis is to determine the difference in quality between the selected methods on the welds made and to develop a technical and economic evaluation. At the beginning of the diploma thesis, a literary study is analyzed with a focus on the principle of individual welding methods, possible defects arising during welding and the weldability of individual types of stainless steels. In the experimental part, the design of the experiment is discussed, which consisted in welding samples of selected weld joints using individual technologies. The welds were then evaluated using non-destructive and destructive tests. Finally, the economic evaluation of both technologies and the return of the equipment were also calculated.
Robotic welding case of linear fluid motor
Střechovský, Jan ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The work deals with the feasibility study of robotic welding of a linear actuator cover. The first part includes a literature review focusing on the specifications and impact of individual welding process components on the appearance and properties of the weld. Some basic calculations necessary for the proper progress of the experiment are also included. The experimental part of the work focuses on finding suitable welding parameters and subsequent evaluation of the welded samples in terms of resulting defects. The following section compares the efficiency of manual and robotic welding. The conclusion of the work summarizes the achieved results and the decision on the feasibility of robotic welding for the given joint.
Laser surface cleaning
Macháček, Martin ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
This thesis covers feasibility of laser cleaning applied to various types of surface contaminations and treatments. In theoretical part of the theses are described basic principles of laser, a machine used in practical section (M200 by 4Jet) is introduced and corrosion and surface treatments are depicted. In practical part of the theses is described the preparation process of testing samples, the cleaning procedure and the results thereof are evaluated with emphasis on feasibility of the operation. The last section of the thesis focuses on comparison between conventional cleaning technologies and that of laser cleaning. Conclusion of the thesis summarises gained insights.
Issues of the LaserHybrid welding method
Znášik, Samuel ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The thesis deals with the issue of using LaserHybrid welding for the energy industry where the combination of laser and arc could facilitate higher quality welds resistant to aggressive environments, corrosion and oxidation. The methods that the hybrid process produce as well as possible replacements for the MIG and MAG methods are explored, as well as the different configurations and their possible impact on the process. The possible use of the technology for hyperbaric welding is also presented. The experimental part is devoted to the welding of refractory martensitic steel used in the power industry for the production of steam turbines. Weld structures at different parameters were investigated and hardnesses were compared.
Use of torch swing for butt weld welding of stainless steel MAG method
Gago, Matúš ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
Diploma thesis of arc welding of stainless steels focused on the MAG method, with a literature study on the issue. The geometries of the butt weld with the preparation of the bevel "Y" and the thickness of materials that are often used on structures used in the energy and food industries (6, 8 and 12 mm) were selected. An experimental study of the effect of MAG welding was performed, with and without oscillation of the welding torch for the "Y" weld. Experimentally verified sample welds of individual types were supplemented by the evaluation of results with fillet welds and submerged arc welds for comparing the consequences of welding with high heat input. The materials used were theoretically evaluated, the possible resulting theoretical material structure was analytically calculated and the results were included in the Scheaffler and WRC 1992 diagram. The mutual weldability of the materials with the equivalent of Crom and Nickel was assessed. And evaluated macrostructure of weld patterns, developed tensile tests and hardness tests to assess the impact of mechanical properties. In the end, recommendations for practice and recommendations for the prevention of errors, which were observed on experimental samples, were set.

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