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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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Materials change of parts for harvester chain production
Houdek, Radim ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The work is focused on the track element, namely the replacement of the crossbar material from steel 27MnCrB5-2 to steel 30MnB5 from which the other parts of the cell, the cubes, and the bar are made and welded by the GMAW method. Changing the material and omitting the preheating phase would reduce the production time of the cell by approximately half the time. The theoretical preheating temperature calculated according to the relevant standard for both steels exceeded 200 ° C. Test specimens imitating the weld between the crossbar and the cube were welded on which a qualitative evaluation was performed. These were weldments of 30MnB5 steel with preheating (sample 10), 30MnB5 steel without preheating (sample 11) and 27MnCrB5-2 steel with preheating (sample 9). In terms of macrostructure, non-penetrations were found on all samples. Martensitic structure was found in all areas by microstructural observation. When measuring the hardness according to the Vickers method, approximately the same hardness profile was obtained in all weld areas of samples 10 and 11. The highest value reached 450 HV1 and exceeds the maximum hardness recommended by the standard. Due to very similar test results for 30MnB5 steel weldments with and without preheating, it is possible not to perform preheating. However, the results may be skewed by the relatively small size of the test specimens. For a reliable evaluation and final decision, it is necessary to perform tests on a real crossbar after complete production.
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Manufacture of Fire-Extinguisher
Holub, Matyáš ; Kubík, Roman (referee) ; Kalivoda, Milan (advisor)
The aim of this work is to find methods how to save in the manufacture of fire extinguisher provided that there is no deterioration in the quality of the product. They are considered two methods. Method A is the current method. Method B is the proposed method. The part of the comparison of the two methods is the price calculation of the fire extinguisher, which has led to savings. In the proposed method time of returns is also calculated when new equipment is being bought.
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Materials change of parts for harvester chain production
Houdek, Radim ; Kubíček, Jaroslav (referee) ; Sigmund, Marian (advisor)
The work is focused on the track element, namely the replacement of the crossbar material from steel 27MnCrB5-2 to steel 30MnB5 from which the other parts of the cell, the cubes, and the bar are made and welded by the GMAW method. Changing the material and omitting the preheating phase would reduce the production time of the cell by approximately half the time. The theoretical preheating temperature calculated according to the relevant standard for both steels exceeded 200 ° C. Test specimens imitating the weld between the crossbar and the cube were welded on which a qualitative evaluation was performed. These were weldments of 30MnB5 steel with preheating (sample 10), 30MnB5 steel without preheating (sample 11) and 27MnCrB5-2 steel with preheating (sample 9). In terms of macrostructure, non-penetrations were found on all samples. Martensitic structure was found in all areas by microstructural observation. When measuring the hardness according to the Vickers method, approximately the same hardness profile was obtained in all weld areas of samples 10 and 11. The highest value reached 450 HV1 and exceeds the maximum hardness recommended by the standard. Due to very similar test results for 30MnB5 steel weldments with and without preheating, it is possible not to perform preheating. However, the results may be skewed by the relatively small size of the test specimens. For a reliable evaluation and final decision, it is necessary to perform tests on a real crossbar after complete production.
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Manufacture of Fire-Extinguisher
Holub, Matyáš ; Kubík, Roman (referee) ; Kalivoda, Milan (advisor)
The aim of this work is to find methods how to save in the manufacture of fire extinguisher provided that there is no deterioration in the quality of the product. They are considered two methods. Method A is the current method. Method B is the proposed method. The part of the comparison of the two methods is the price calculation of the fire extinguisher, which has led to savings. In the proposed method time of returns is also calculated when new equipment is being bought.
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Využití metody svařování v ochranné atmosféře aktivního plynu ve strojírenské praxi
Černý, Oldřich
The aim of this bachelor thesis is joining metals by welding, namely metal active gas welding. The first part is dedicated to different methods of welding in engineering practice and describes the best-known methods and principles in detail. The second part focuses on the selected welding process. It explains the principle of the method, metal transfer from the electrode to the parent material and describes the welding equipment used for this method. The final part deals with filler materials, active gases and parent materials used in practice.
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