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Numeric simulation of surfacing turbine rotors pinot pins
Tkaný, Jan ; Mrňa, Libor (referee) ; Daněk, Ladislav (advisor)
The master´s diploma thesis elaborated as the master's degree M-STG Manufacturing Technology solves surfacing problems in the simulations of surfacing turbine rotors pinot pins. The work was seen as a preparatory work before the real surfacing. Topic commissioned by Siemens Industrial Turbomachinery Ltd. For welding plates test has been used the method of SAW and the base material was identical to turbine rotor material, X22CrMoV 12-1. Additional material was Fluxocord 42. Simulations were carried out in programs SYSWELD and Visual - WELD. The output of the simulation software are temperature and stress fields, material structures and creations of the CCT diagrams at the base material, filler material, and mixed area.
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Welding of turbine rotor materials
Cvoligová, Hana ; Kubíček, Jaroslav (referee) ; Daněk, Ladislav (advisor)
In the Visual - Weld and Sysweld programs, a simplified simulation of the welding process of the turbine rotor made of 27NiCrMoV 15-6 substance was performed. The numerical analysis took place at the equal temperature of preheating and it covered both minimal and maximal percent chemical composition. The simulation proved that the percent deviations of elements in the substance change the speed necessary for reaching of the bainitic structure. Simulation results were verified by a practical experiment. Two weld beads were welded to a base substance by MIG method: one bead at the temperature of 200°C, the other one at the temperature of 300°C, both with the same specific input caloric QS. Both micro and macrostructure of the base substance and TOO was evaluated, and the progression of the hardness was measured as well. The deviations fell within the acceptable 15% range.
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Numeric simulation welding of the turbine vane and rotor
Dohnal, Ivo ; Slováček, Marek (referee) ; Daněk, Ladislav (advisor)
Numeric simulation welding of the turbine vane and rotor - master’s thesis is ordered by the Siemens Industrial Turbomachinery ltd. company. Simulation welding is done in program SYSWELD. Used welding materials are X22CrMoV12-1 (turbine vane), 30CrMoNiV5-11 (rotor), TOPCORE 838 B (additional material). These are temperature-resistant and fire-resistant welding materials. The SYSWELD program works on the principle of finite elements method. By SYSWELD is done the evaluation of temperature and stress fields and material structure after welding. Here is a part , which deals with computations of welding crevices.
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Computational Modelling of Welding and Heat Treatment Process of Steel with Application of Elastic-Viscoplastic Material Model
Jarý, Milan ; Daněk, Ladislav (referee) ; Dymáček, Petr (referee) ; Junek, Lubomír (advisor)
This dissertation thesis deals with the improvement of computational approaches for prediction of residual stresses in welded joints of welded structures in order to ensure greater compliance of the calculated results with the real conditions of welding and heat treatment. The improvement of computational approaches is based on application of elastic-viscoplastic material models which are able (compared with elastic-plastic material models) to take into account the viscoplastic processes ongoing during welding and heat treatment. This leads to more accurate calculated results which enter into further assessment of limit states and directly decide on the safety and lifetime of welded structures. Performed computational and experimental works, confronted with results published in the world, confirm the influence and benefit of application of elastic-viscoplastic material models in the frame of welding and heat treatment numerical analyses. Therefore elastic-viscoplastic material model is further applied in solution of practical project solved by IAM Brno. Solution of this project, whose aim is the development of repair of dissimilar metal welds (without post-weld heat treatment) in Dukovany and Temelin nuclear power plants using "Weld overlay method", has confirmed that application of elastic-viscoplastic material model leads to more accurate calculated results. For this reason the elastic-viscoplastic computational approach will be included into all future tasks of IAM Brno.
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Welding of turbine rotor materials.
Richter, Tomáš ; Slováček, Marek (referee) ; Daněk, Ladislav (advisor)
Master’s thesis titled Welding of turbine rotor materials discusses evaluation of welding parameters by numerical simulation in software SYSWELD and Visual - WELD. Base material 23 CrMoNiWV 8-8 is welded by submerged arc welding technology. Used flux is F 26G and electrode is flux-cored wire TOPCORE 838 B. Material structures, hardness, values of residual stresses and distortion of weldment for this process are calculated by using the numerical analysis.
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Development of Models of Al Alloys Behaviour for Applications in Numerical Simulations of Welding and Heat Treatment
Vaněk, Mojmír ; Věchet, Stanislav (referee) ; Neumann, Heinz (referee) ; Daněk, Ladislav (advisor)
The thesis deals with methodology for computational approaches for numerical simulations of welding and heat treatment of aluminium alloys. The thesis describes improvement of the current methodology for metallurgical part of the numerical analysis of welding, which is important mainly for prediction of dimensions of the heat affected zone (and deformations). The improvement was carried out based on CHD diagram that describes precipitation and dissolution of phases during continuous heating. The thesis also describes carried material measurements (measurement of chemical composition, dilatometric tests, tensile tests of several conditions of materials at temperatures up to 500 °C and measurement of aging curves), which allowed to significantly refine analysis results for the alloys EN AW-5083 and EN AW-6082. Based on an evaluation of the measurements, several conclusions were made. They can be useful for creation of material databases of other aluminium alloys. The thesis also describes quantification of dependence between tensile strength and yield strength on the Vickers hardness for different conditions of EN AW-6082. There is also methodology for numerical simulation of the heat treatment process of heat treatable Al alloys in the dissertation. The methodology is completely new approach which has never been published so far. Application of this method is based on user changes of the material database in software Sysweld after relatively easy measurement of aging curves. Therefore, the methodology can be considered as promising for application in industrial practice.
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Prediction of welding joint distortion by computer simulation.
Vaněk, Mojmír ; Slováček, Marek (referee) ; Daněk, Ladislav (advisor)
In this master’s thesis there are set down dependencies of distortion of T-joints on the size of heat input and welding speed. Dependencies were found for single- and double-fillet welds, for single- and multiple-pass welding. The computer simulations were carried out in programs Visual-Weld and SYSWELD. The size of the melted zones, stress fields, material structure and hardness of the weld specimens were specified. Simulation results were compared with experimentally detected values.
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Development of Models of Al Alloys Behaviour for Applications in Numerical Simulations of Welding and Heat Treatment
Vaněk, Mojmír ; Věchet, Stanislav (referee) ; Neumann, Heinz (referee) ; Daněk, Ladislav (advisor)
The thesis deals with methodology for computational approaches for numerical simulations of welding and heat treatment of aluminium alloys. The thesis describes improvement of the current methodology for metallurgical part of the numerical analysis of welding, which is important mainly for prediction of dimensions of the heat affected zone (and deformations). The improvement was carried out based on CHD diagram that describes precipitation and dissolution of phases during continuous heating. The thesis also describes carried material measurements (measurement of chemical composition, dilatometric tests, tensile tests of several conditions of materials at temperatures up to 500 °C and measurement of aging curves), which allowed to significantly refine analysis results for the alloys EN AW-5083 and EN AW-6082. Based on an evaluation of the measurements, several conclusions were made. They can be useful for creation of material databases of other aluminium alloys. The thesis also describes quantification of dependence between tensile strength and yield strength on the Vickers hardness for different conditions of EN AW-6082. There is also methodology for numerical simulation of the heat treatment process of heat treatable Al alloys in the dissertation. The methodology is completely new approach which has never been published so far. Application of this method is based on user changes of the material database in software Sysweld after relatively easy measurement of aging curves. Therefore, the methodology can be considered as promising for application in industrial practice.
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