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Porosity during welding aluminous alloys
Hájková, Alena ; Daněk, Ladislav (referee) ; Sigmund, Marian (advisor)
This thesis deals with the problem of occurrence of porosity in aluminous alloys and the methods of their repair in the company IFE. Theoretical part is aimed on the current state of porosity and the ways in which the be pores can be repaired. Used technologies of repairs are TIG welding and cementing. The practical part consists of experiment in which is used a method of cementing on specific part.
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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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Evaluation of quality welds on chains for harvester
Teuer, Tomáš ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The diploma thesis examines the influence of setting welding parameters and welding process on the resulting structure and strength of the welded joint of harvester chains. The theoretical part discusses the problem of weldability of pine steels by using method “135” with the possibility of destructive or non-destructive testing of welded joints. In the practical part, this matter is examined on a specific weldment, the harvester chain. Cross member with a cube welded in two ways by method 135, followed by an assessment of the performance of welds. The results of the evaluation are written down in the manual.
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Weldability problems of duplex mixer blades
Bryksí, Petr ; Záděra, Antonín (referee) ; Sigmund, Marian (advisor)
The diploma thesis deals with the analysis of the causes of fracture of axial stirrer blades made of duplex material 1.4462 for gypsum suspension in Ledvice Power Plant. The theoretical part deals with the problem of welding of duplex steels. The practical part of the work includes the procedure from the preparation of the sample for metallographic, fractographic observation, chemical composition and hardness test. For our experiment, areas at the fracture point were cut out from the supplied blades and then measurements were made on them. Subsequently, we then evaluated the measured data at the fracture site of the blades and the weld joint area. Based on the analysis, technological and design recommendations for further blade production were made.
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Compared HAZ the methods of welding TIG, MAG and CMT
Šoulák, Petr ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
The bachelor thesis was to compare the HAZ size for the TIG, MAG and CMT methods. The welded materials were low carbon steel and austenitic stainless steel. Samples of 250x50 mm size and 2 mm thick were welded with butt weld without a gap. In the first part of experiment, samples were welded at the same welding speed. The second part concerned only CMT, where the optimal welding speed was used. For selected samples, the HAZ size was measured and compared in macroscopic images.
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Non-destructive testing of welds
Šaloun, Jan ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
This thesis describes non-destructive testing (NDT) of fusion welds of metals. There are five fundament methods of NDT discussed in the theoretical part – visual and magnetic particle inspection, ultrasonic, radiography and penetrant testing. Principles of methods, examining procedures and their evaluations are described. The methods are compared with each other. In the experimental part of the thesis two samples of welding joints were welded and tested by selected methods. To verify correctness of the indicated defects, metallographic samples were made. At the conclusion practical results are compared with theoretical statements.
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Analysis of Influence of Manufacturing Technology on Utility Properties of a Reducing Valve Part
Novotný, Michal ; Sigmund, Marian (referee) ; Řiháček, Jan (advisor)
The present work is focused on the comparison of the currently used technology for the production of reducing resistors, i.e. electroerosive machining in combination with soldering on one side and the use of a suitable additive technology on the other hand. In addition to the purely technological aspects, such as the individual production processes or their preparation, economic aspects are also compared, supplemented by an assessment of the delivery times of the finished parts. The analysis is carried out The environmental impact of both production approaches is also analysed. The individual comparisons form the basis for to assess whether the replacement of the conventional manufacturing approach by additive manufacturing is advantageous in this case. The results of this assessment can then be used for future applications of the considered additive manufacturing approaches for similar components.
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Implementation of automatic welding machine to production of fittings
Cícha, Tadeáš ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The Diploma Thesis is focused on the implementation of FCAW welding technology to the manufacturing process of a mechanical engineering company. One part of implementation is partial automation of manufacturing process with positioner machine which is connected to the welding source. Practical part of Diploma Thesis includes the verification of the weldability of used materials and assigning of pWPS for subsequent qualification of the welding process WPQR with the welding technology FCAW.
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Influence of shielding gas on weld properties of conductive laser welding of sheet from carbon steel
Kotrík, Marcel ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
In the thesis are analysed influences of three shield gases, based on literary pursuit. Compared was influence of the gas consisting of pure Ar, mixture Ar with 3vol.% CO2 and the mixture Ar with 18vol.% CO2 on mechanical properties of conduction laser welded blunt welds made from structural steel DC01 and S235JR with thickness 3mm and 2mm. Compared were strength properties of the welds in tension, weld hardness and hardness of the heat affected area under the low stress. Further was observed and compared stream of the gases during welding process and its influences on the appearance of the trial welds. On the metallographical cuts of the welds were evaluated mistakes and dimensions of the welds.
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