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Evaluation of the fillet weld geometry on process parameters for laser welding of stainless steel
Polášek, Marek ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The present thesis deals with welding of samples to examine the resulting geometry of the weld in dependence on process parameters of the laser. Welding was carried out without additional material using a fibre laser. The material used was stainless steel ČSN EN 17 241. The values of regression coefficients of the resulting graphs show that the changes in the weld geometry - width and depth - vary quite linearly depending on the welding performance. Especially the weld depth is a common requirement in technical practice; the measured results of the experiment can be used to set the process parameters to achieve the desired depth of weld. Some welds exhibit weld defects such as porosity caused by formation of the keyhole due to a large dynamics of the process. The technical-economic evaluation offers a price estimate for one meter of weld for each welding speed used.
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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 welded joints after fatigue tests
Kučera, Ondřej ; Doubrava, Marek (referee) ; Havlík, Petr (advisor)
This bachelor thesis deals with analysis of welded joints after fatigue tests . The first part of this thesis, literary research, discusses weldability of carbon steels and low-alloy steels and effect of chemical composition on weldability of materials. Further there are zones of welded joints, their microstructure and mechanisms applied described in this thesis. There are defects occurring in welded joints and their common causes and remedies described in the part of literary research dealing with defects. And the final part of the literary research deals with material fatigue, fatigue of welded joints and effect of defects, fusion zone and heat-affected zone on the fatigue of welded joints. In the experimetal part of bachelor thesis there is described experimental material, results obtain process and discussion of results.
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Locating welds defects on cranes.
Zíka, Luboš ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The diploma thesis deals with the problematics of weld defects of cranes localisation and check. The aim is to analyse non-destructive methods, monitor the occurence of defects and their form and also to suggest the procedure of correction. The work is divided into a theoretical and practical part. In the theoretical part, there is an analysis of individual methods of non-destructive testing that are used for weld check on a particular girder. There is also an analysis of welding technologies used when making a crane girder. The practical part deals with evaluation of weld defects using two methods of non-destructive testing. Furthermore, statistics of defects is realised. In conclusion, the statistics outcome is resumed and evaluated.
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Hodnocení kvality svaru pomocí nedestruktivních technologií
Jakeš, Jakub
The bachelor's thesis deals with an analysis of individual non-destructive methods that are used in practice to check welds and welded structures. The introductory part discusses the principles of individual welding methods and the problems that may arise during the welding process. In the next chapter, individual methods of non-destructive testing are described, where their origin, principle and accessories for their application and their deployment in practice are specified. Much attention is paid to the acoustic emission method, for which the individual specifications are described in more detail. In the final of thesis, a verification experiment is performed, on which the functionality of the acoustic emission is demonstrated.
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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 welded joints after fatigue tests
Kučera, Ondřej ; Doubrava, Marek (referee) ; Havlík, Petr (advisor)
This bachelor thesis deals with analysis of welded joints after fatigue tests . The first part of this thesis, literary research, discusses weldability of carbon steels and low-alloy steels and effect of chemical composition on weldability of materials. Further there are zones of welded joints, their microstructure and mechanisms applied described in this thesis. There are defects occurring in welded joints and their common causes and remedies described in the part of literary research dealing with defects. And the final part of the literary research deals with material fatigue, fatigue of welded joints and effect of defects, fusion zone and heat-affected zone on the fatigue of welded joints. In the experimetal part of bachelor thesis there is described experimental material, results obtain process and discussion of results.
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Locating welds defects on cranes.
Zíka, Luboš ; Hála, Michal (referee) ; Kubíček, Jaroslav (advisor)
The diploma thesis deals with the problematics of weld defects of cranes localisation and check. The aim is to analyse non-destructive methods, monitor the occurence of defects and their form and also to suggest the procedure of correction. The work is divided into a theoretical and practical part. In the theoretical part, there is an analysis of individual methods of non-destructive testing that are used for weld check on a particular girder. There is also an analysis of welding technologies used when making a crane girder. The practical part deals with evaluation of weld defects using two methods of non-destructive testing. Furthermore, statistics of defects is realised. In conclusion, the statistics outcome is resumed and evaluated.
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Evaluation of the fillet weld geometry on process parameters for laser welding of stainless steel
Polášek, Marek ; Hála, Michal (referee) ; Mrňa, Libor (advisor)
The present thesis deals with welding of samples to examine the resulting geometry of the weld in dependence on process parameters of the laser. Welding was carried out without additional material using a fibre laser. The material used was stainless steel ČSN EN 17 241. The values of regression coefficients of the resulting graphs show that the changes in the weld geometry - width and depth - vary quite linearly depending on the welding performance. Especially the weld depth is a common requirement in technical practice; the measured results of the experiment can be used to set the process parameters to achieve the desired depth of weld. Some welds exhibit weld defects such as porosity caused by formation of the keyhole due to a large dynamics of the process. The technical-economic evaluation offers a price estimate for one meter of weld for each welding speed used.
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