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Corrosion resistance of cast duplex stainless steels
Müller, Peter ; Záděra, Antonín (referee) ; Pernica, Vítězslav (advisor)
The master’s thesis deals with corrosion resistance of cast duplex steels. In the first part the corrosion mechanisms and their individual types are described, the second part characterizes the types of stainless steels in terms of their properties, use, structural components, and their impact on mechanical and corrosion properties of steels. Individual chapter is dedicated to duplex steels. In the experimental part the resistance of 1.4517 steel against pitting corrosion depending on the alloy contents and the PREN value was investigated. Four specimens graded according to PREN were cast. Supplemented with sample stirrer blade which was affected by corrosion during service they were subjected to corrosion test according to ASTM G48-11 standard in 6% FeCl3 solution. Cast specimens were subjected to tensile test and impact test.
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Thermal spray by electric arc
Eliáš, Vojtěch ; Sigmund, Marian (referee) ; Kubíček, Jaroslav (advisor)
This thesis deals with the issue of thermal spraying by means of an electric arc. First of all, a theoretical part is processed using a literary study dealing with corrosion and thermal spraying technology. The experimental part contains a description of the technological procedure and evaluation of four thermally sprayed samples. Zinacor 850, consisting of 85% zinc and 15% aluminum, was used as a coating. The evaluation involves measurements of thickness, adhesion and roughness as well as the macro-structural analysis of the coating. Two samples showed unusually low adhesion, and all samples also had a large fluctuation of the measured thicknesses. This was also confirmed by the macro-structural analysis, which showed that the sample with low adhesion also had high porosity. These defects may have multiple causes, but the recommendation for further practice is to reduce the spraying distance from the base material.
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Structure and properties of martensitic stainless steels
Rimko, Marcel ; Čamek, Libor (referee) ; Záděra, Antonín (advisor)
The final thesis deals with martensitic stainless steel and their mechanical properties. The theoretical part consists of information about corrosion, chemical composition, heat treatment and mechanical properties of various types of steel. The practical part deals with the influence of the cooling rate during heat treatment and nickel content on the mechanical properties and microstructure of the GX4CrNi13-4 steel.
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Manufacture of gastronomic equipment of stainless steel
Macková, Ivana ; Varhaník, Matúš (referee) ; Kalivoda, Milan (advisor)
The bachelor thesis seals with corrosion, stainless steels and surface treatments of steels, which prevent corrosive disruption of the material. Furthermore, the work deals with the design of the production of non-rotating component with a flange made of austenitic stainless steel X5CrNi 18-10. A blank is cut out on sheet shears. A blank is formed into the desire shape on a CYS 320 press by deep drawing technology, and later a flange is cut on LEXN 100 C press. The economic evaluation of production is set at a model situation of 100 000 pcs/year.
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Monitoring Of Bridges Corrosion Level
Krejčí, Jakub
Corrosive damage level of bridge constructions becomes high discussed topic with regard to some recent incidents. Current system of inspections is based mostly only on visual inspections in the Czech Republic. Our solution proposes to build-in a humidity sensor inside a bridge structure to detect leaking water and damage level during long period. Text focuses on description of basic principles of humidity measurement and performed experiments with sensors implemented in porous material showing possibility of measurement inside a structure. Finally, a market research of commercially available sensors is documented with narrowing selection suitable for this application.
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Materials For Biodegradable Bones Based On Fe
Hrabovský, Jan
The thesis deals with biodegradable bone implants which must have good mechanical properties and also good compatibility with the human body. The thesis contains literary research in the area of bone physiology, biogenic materials and implants for the human body. The thesis focues on the selection of suitable materials for biogenic implants.
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Diagnostics of bridge structure
Nápravník, Petr ; Žítt, Petr (referee) ; Láník, Jaromír (advisor)
This bachelor´s thesis deals with construction-technical survey of a highway bridge no. D1-243 across Ripska street at suburbs of Brno. Theoretical part contains bridge terminology, inspections, problematics of prefabricated beams I-73, construction-technical survey and description of laboratory tests. Practical part deals with making of a construction-technical survey, evaluation of construction parts and a summary of results.
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Survey and Diagnostics of Reinforced Concrete Structure
Haloun, Jan ; Heřmánková, Věra (referee) ; Anton, Ondřej (advisor)
The first part of this diploma thesis is about late and current methods used in Engineering surveys. The theoretical part is focused on description of individual testing methods and their evaluation based on relevant standarts. Detailed description of diagnostic methods is dependent on methods used in a practical part. The practical part is focused on defining of material characteristics of used materials and way of reinforcing of reinforced concrete elements. Based on those defined pieces of information the static recalculation of girder and pile was made.
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Plasma cleaning of corroded plumb objects
Bubnová, Kateřina ; Grossmannová, Hana (referee) ; Krčma, František (advisor)
This bachelor thesis deals with the application of low-pressure hydrogen plasma to lead corrosion products. There are many historical objects and these objects require careful removal of corrosion layers. Therefore, it is necessary to optimize the treatment process in order not to destroy real historical artefacts in the future. This work is focused on lead, which has not been explored by this method yet. Model samples with corrosion were prepared for comparison and these samples corrode in vapors of concentrated acetic acid and formic acid. There were three working temperatures for plasma chemical treatment because of the low lead melting point and the atomic heating. Argon-hydrogen plasma and hydrogen plasma was applied to 12 corroded samples during the experiment. Process progress was monitored by optical emission spectrometry and surface analysis was performed by SEM, XRD and EDX analysis. The results of these analyzes showed that the most appropriate temperature for plasma chemical treatment was 130 ° C. Based on the obtained results many suggesstions and ideas were obtained for the future research like using of pulse mode and gas composition.
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Preparation of historical binders with high resistance to ambient influences
Nehybka, Josef ; Palovčík, Jakub (referee) ; Opravil, Tomáš (advisor)
This master’s thesis is focused on preparation of the mortar mixtures inspired by roman cement with a great resistivity against the corrosion environment, especially a seawater. There were prepared samples of a roman cement containing of pure lime and various artificial pozzolans and natural tuff which were used as pozzolan admixtures. The task of this work is to explore possibility of using pure lime and for example pozzolan admixture which can resist against the corrosive environment like a roman cement. There were prepared a lot of various samples which were tested separately on their mechanical characteristics before and after their exposure of the influence of the corrosive environment. There were used X-ray diffraction analysis for the characterization of a phase composition of the raw materials and some selected samples.
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