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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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Use of laser-TIG hybrid technology for boron-doped high-strength steels
Kachlíř, Jaromír ; Šebestová, Hana (referee) ; Mrňa, Libor (advisor)
This thesis deals with the usage of arc preheating for welding high strength boron enhanced steel 22MnB5 using hybrid technology known as laserTIG and also its impact on the final weld compared to welds welded by only the laser or the arc method. During the experiment I welded five sheets of the above mentioned steel 1,3 or 1,9 milimeters wide. Except for the welds fabricated by the laser and the TIG method was the only variable the electric current of the arc (I = 20, 40, or 60 A). Welds welded this way were compared based on strength limits measured by the tensile tests. Additionally were they compared according to the metalographic survey and the progress of weld hardness, calculated using the Vickers hardness test.
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Use of laser-TIG hybrid technology for welding of different materials used in power engineering
Žák, Tomáš ; Beran, David (referee) ; Mrňa, Libor (advisor)
Thesis is focused on analyzing the influence of preheating process parameters using electric arc from TIG torch during laser welding on weld properties of stainless steel and carbon steel with higher strength. In this thesis experiment was done in which metal sheets 3 mm thick from X12Cr13 and S355 steels were welded. Welding was done first with using only laser, then laser with TIG preheating and lastly laser with preheated material by induction heater. When TIG preheating was used than set welding current was changed on the power source. The welds were subsequently evaluated based on macrostructure, microstructure and Vickers hardness test.
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Study of properties of laser welds of Hardox 450 material using arc preheating
Debs, Martin ; Kubíček, Jaroslav (referee) ; Mrňa, Libor (advisor)
In this thesis is studied the influence of arc TIG preheating during laser welding of 2 mm Hardox 450 material sheets. This material achieves its good mechanical properties by processes of heat treatment. That causes problems during welding because of heat degradation. Experimental sheets were welded within various configurations of welding parameters and positions of TIG nozzle. Testing specimens were cut out by laser and were used for tension testing, Vickers hardness testing and metallographical testing (macro and microstructure). The results of using the second heat source are: wider heat affected zone, smoother transitions among its zones, reduction of toughness and hardness, finer grain structure and occurring ferritic microstructure. This hybrid technology, combination of laser welding and TIG preheating, is very productive creating joints with greatly good quality. The thesis also contains a comparison with common MAG welding method.
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Use of the preheating by electric arc during laser welding of steels with higher carbon content
Mach, Martin ; Sigmund, Marian (referee) ; Mrňa, Libor (advisor)
The thesis is focused on the study of the use of electric arc preheating, in this case source WIG, during laser welding of steel with a higher carbon content, specifically for this work steel 1.1191 thickness 2 mm. Based on the calculation of the carbon equivalent, the preheating was determined to 208 °C. The welding parameters were selected on the basis of the first experiments. In the experimental section, the samples were welded with laser with preheating using a source WIG, which were then made to a tensile test, Vickers microhardness, macrostructure and microstructure. By using a second heat source, the heat-affected area of the samples was expanded. Samples that cracked in the middle of the weld during the tensile test were heat influenced by cutting samples. The remaining samples was broken in the base material, thus the weld produced was of good quality. Combination of laser welding with WIG electric arc preheating is a very productive method over conventional methods and one of the few pre-heating solutions for laser welding. These are the initial experiments for the use of the WIG arc for preheating in laser welding, to be followed by further research, mainly for the automotive industry.
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Welding of the framework from aluminium alloys
Rašek, Ondřej ; Daněk, Ladislav (referee) ; Kubíček, Jaroslav (advisor)
For TIG welding of transformer fame is important enough weld root fusion, however exposed surfaces must remain unaffected. Three types of test were made to determine properties of welds under different conditions. Tests were macroscopic inspection, tensile test and fracture test. Next was economic evaluation of different methods. Best results were for single layer weld with pre-heated material.
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Solder Wave Process Optimization
Procházka, Martin ; Brno, Martin Štěpánek HONEYWELL (referee) ; Starý, Jiří (advisor)
This work describes solder wave process and it‘s optimalization. It informs us about wave soldering and describes it’s fragments. Next it is described partition of fluxes and their properties. In practical part is described researching of defects on PCB’s and analysis of possible reason of defects, measurement of the weight of sprayed flux and measurement of solderable profile.
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Elektrická rezistivita podstechiometrického TiO2 vyrobeného plazmovým nástřikem
Ctibor, Pavel ; Sedláček, J. ; Neufuss, Karel
The work is concentrated on electric resistivity of plasma sprayed titania TiO2. Synthetic conventional TiO2 powder and powder prepared by agglomeration of nanopowder particles were sprayed and measured. Spraying was carried out using the water-stabilized plasma system (WSP®) and resistivity measurement was applied on TiO2 layers detached from the substrate. Variations in basic spray conditions – spray distance, feedindg distance and substrate preheating temperature were commented from the point of view of their influence on electric resistivity.
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Elektrická rezistivita podstechiometrického TiO2 vyrobeného plazmovým nástřikem
Ctibor, Pavel ; Sedláček, J. ; Neufuss, Karel
The work is concentrated on electric resistivity of plasma sprayed titania TiO2. Synthetic conventional TiO2 powder and powder prepared by agglomeration of nanopowder particles were sprayed and measured. Spraying was carried out using the water-stabilized plasma system (WSP®) and resistivity measurement was applied on TiO2 layers detached from the substrate. Variations in basic spray conditions – spray distance, feedindg distance and substrate preheating temperature were commented from the point of view of their influence on electric resistivity.
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