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Structure and properties of weldment of rotor steels
Jech, David ; Jan,, Vít (referee) ; Foret, Rudolf (advisor)
The object of this thesis is to assess the structural stability of heterogeneous weld joint, which consists of two different base materials (16,537 steel and 16,236 steel) and weld metal NiCrMo2.5-IG with buttering layer P24-IG. All these materials belong to the group of low-alloyed creep-resistant steels that are to be used mainly in the power industry. The weld joint was made by application of the TIG hot wire welding method. Structural stability of this joint was evaluated by carbon redistribution and microstructural changes after annealing in temperature 300 °C and 400 °C during 500 hours. For modelling the phase composition of particular steels was used the ThermoCalc software. All gained results should be employed to appraise whether the heterogeneous weld joint of the steam turbine´s rotor is eligible for long-term operation in hard working conditions.
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Comparision of FEM models of joints
Hlaváč, Martin ; Hrůza, Václav (referee) ; Pokorný, Přemysl (advisor)
This thesis deals with the comparison of alternative models of the simplified joints used in the FEM models of complex models with detailed joint details. This is essentially a screw connection with dowel bolt and standard bolt, weld connection "T" and overlap weld connection. Individual connections are compared in the simulation results of matching models.
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Modelling of Phase Composition of Heat Resistant Steels and their Welds
Dvořáček, Ondřej ; Foret, Rudolf (referee) ; Jan, Vít (advisor)
This work deals with the effects of high temperature exposition of low alloyed creep resistant steels on their structural stability and structural stability of their weld joint. The theoretical part of this work gives an overview of creep resistant steels considering their chemical and phase composition and their connection to high temperature mechanical properties. The CALPHAD method is presented as generally accepted approach for equilibrated calculations and Thermo-Calc and DICTRA software packages are introduced as CALPHAD applications. Thermo-Calc software is used for calculation of phase composition of the examined materials and for calculation of the phase diagrams. Software DICTRA is used for simulations of diffusion controlled phase reactions in the analysed weld. Experimentally one weld joint of the steels 15 128 and 15 313 has been studied after four different annealing procedures. The experimental results include chemical profiles across the welds, microhardness profiles and metallographic analysis of significant regions of the welds. These experimental results are compared with the simulation results. The comparison shows a reasonable agreement between experimental and simulation data.
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Diffusion of carbon in welding joints of low alloys and high alloy steels.
Zdvořáček, Marek ; Rek, Antonín (referee) ; Stránský, Karel (advisor)
Content of a document result measurements and analysis carbon´s diffusion at welding joint created from hight alloyed austenitic steel CSN 417242 and not alloyed steel CSN 412 050. Samples have been put throught isothermal anneal in a temperature range 500 °C up to 1100°C. Aim one´s effort to metalographyic quantification carburized and uncarburized zone. The next part of the document content measuring x-ray energy through microanalysis, where has been record course of a carbon disintegration and selected replacements elements at whole length of the welding joint . At the end of experimental part has been gauged course microhardness HV 0,05 at whole lenght of welding joint, from an acquired data has been chose the most optimal temperature of isothermal anneal, to produce the smallest structural notch.
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Structural Stability of Creep-Resistant Steels and their Weldmets
Šohaj, Pavel ; Jan, Vít (referee) ; Foret, Rudolf (advisor)
The structural stability of creep-resistant steels P22, P91 and Eurofer´97 and structural stability of weld joint P22/P91 have been studied. The microstructural changes during annealing at temperatures of 500 – 900°C were examined. The state of equilibrium have been simulated using the ThermoCalc software. The computed results were compared with published data. A good agreement between the simulation and the published data was observed.
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Bridge crossing over Svitava river and railway track in Blansko
Smělíková, Petra ; Konečný, Vojtěch (referee) ; Křižan, Lukáš (advisor)
The aim of the Diploma Thesis is elaboration of study of bridge crossing over the Svitava river and ČD railway track in Blansko. It concerns a five-pole steel beam road bridge with through-span which carries road of the third category. The static system of the construction is solved as solid-web beam of 1.3 meters height which is in three middle spans reinforced by truss construction with top chord and system of diagonals without verticals. The height of the main beam where reinforced by trusswork is 4.75 meters. The width of spans in the road axis is 18.5 + 30.525 + 44.4 + 30.525 + 18,5 metres. The bridge deck consists of steel cross beams bonded with reinforced concrete slab of 200 millimeters of thickness. The drive-through width of the roadway is 7.0 meters. The bridge is fitted with right-sided walkway placed on steel cantilevers. The walk-through width of the walkway is 3.0 meters. Material used is S355 Steel, C30/37 Concrete and S460 Steel which is used for marginal spans of the bridge. Load-bearing construction is assessed in compliance with current technical requirements laid down by European Directives, so called “Eurocodes”. The calculation of inner powers is performed using the Scia Engineer 2013.1 software.
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The Sport Hall in Prostějov
Houška, Daniel ; Štrba, Michal (referee) ; Šmak, Milan (advisor)
The goal of the submitted thesis is a design and assessment of a steel load-bearing structure of a multipurpose sports hall situated in Prostějov. The floor plan measurements of the object are 38x54 m with the maximum ceiling height of 9,5 m. Final design variant was chosen on the basis of two preliminary drafts, both processed according to standard ČSN EN. The structure is designed with respect to ultimate and serviceability limit states. The construction consists of 10 cross-links spaced by 6,0 m. The spatial rigidity of the structure’s main load-bearing system is provided by spatial elliptic trussed girders, longitudinal and sway bracings. Roof cladding is carried by purlins placed on trusses. Steel columns are designed as a part of gable walls. The project was carried out in Scia Engineer 2014 software. Some particular elements were subsequently assessed by means of manual calculation. The thesis also includes assessment of joints, construction details and drawing documentation.
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Sport hall in Písek
Družbík, Jiří ; Štrba, Michal (referee) ; Šmak, Milan (advisor)
The theme of the master’s thesis is to design steel structures sports hall. The proposal is developed in three variants according to ČSN EN. The work addresses the static effect of the steel structure and design of parts and materials design. Plan dimensions are 60x38m, max. internal height is 9,3m. The structure is designed for ultimate limit states and serviceability. The supporting structure is designed as roof arches surround an elliptical girder. In both gable walls are designed steel columns. The work also details and solution design. Sports hall was solved in Scia Engineer 2011 and includes a drawing documentation.
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Non-destructive methods of control of welded joints
Černický, Martin ; Šlais, Miroslav (referee) ; Dohnal, Ivo (advisor)
The thesis elaborated in frame of bachelor studies branch mechanical engineering. The thesis is submitting research of present methods of non-destructive control of welded joints. Pursuant to of the literary pursuit the present methods of control of welded joints were written. First it mentioned problematics of defect of welded joints. After it is mentioned a summary of principles and application of methods of non-destructive control of welded joints.
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Structure and properties of welded joints of steam turbine rotor
Machala, Jan ; Hutařová, Simona (referee) ; Juliš, Martin (advisor)
This thesis deals with the assessment of the structural-mechanical properties of welded joints of steam turbine rotor. Experimental weld material is low alloy steel 30CrMoNiV5-11 in the state after the artificial degradation. The theoretical part of the literary researches the issue, focusing on the weldability of different types of steel used in the energy industry, the metallurgical processes in welding and provides an overview of the most important methods of welding. Great attention is paid to the evaluation of weld quality in accordance with relevant standards and destructive and non-destructive testing of welded joints. In the experimental part of this work was carried out measurements of hardness and microhardness of the weldment by Vickers and evaluation of the microstructure by light microscopy. The obtained values and information about the properties of the material after artificial degradation were compared with previously obtained experimental results in the default state (after annealing).
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