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History of Iron and steelworks Třinecké Železárny
Niemczyk, Roman ; Němec, Karel (referee) ; Věchet, Stanislav (advisor)
The bachelor´s thesis is a technical summary and it is describing the history of Třinecké železárny since its creation in the 1850s to the present. The history of iron processing is briefly described. Furthermore, the thesis focuses to manufacturing process of Třinecké železárny and also to iron and steel production technology. At the last part are decribed typical products of Třinecké železány and future prospects of ironworks.
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Structure and properties of magnesium alloys Mg-Ca-Zn
Hlavnička, Jiří ; Pacal, Bohumil (referee) ; Doležal, Pavel (advisor)
This master’s thesis deals with design and preparation of a new biodegradable magnesium alloy based on Mg-Ca-Zn. Based on information from literature, the Mg-3Zn-2Ca alloy was designed. The base material was produced by gravity casting and the evaluation in the as-cast and heat treated state was performed. For preparation of the experimental material, following methods were designed: squeeze casting, hot rolling and the ECAP. During preparation by hot rolling, no optimal conditions were found and significant cracks occurred in both as-cast and heat treated material. In the case of experimental material, prepared by the ECAP method with back-pressure, better combination of stress-strain properties was observed. Also the squeeze casting method showed improvement; especially the amount of casting defects was eliminated. The evaluation of microstructure and mechanical properties was performed by the light and scanning electron microscopy, RTG phase analysis and the tensile and compression tests.
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Production of towing hook
Frýdl, Pavel ; Štroner, Marek (referee) ; Lidmila, Zdeněk (advisor)
Requirements for the creation of a new technological process of manufacturing of towing hooks were cost savings by optimizing the initial blank and by creating semi automatic workplace. Selecting longitudinal rolling technology for manufacturing preform piece occurs to shorten production times and substantial material savings. By rolling of blank are secured always the exact dimensions of the preform piece and through a chain conveyors is facilitated handling with material for workers and reduced production time of forging line. By introduction of the proposed manufacturing method of towing hooks depending on the size of the series 30000 hooks per year will be achieved annually savings of over 4.000.000 CZK. Return of investments for the acquisition and adjustment of forging rolls and conveyors is 2,2 years.
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Design of rolling mill for flexible single chamber tubes
Maštera, Lukáš ; Tůma, Jiří (referee) ; Blecha, Radim (advisor)
The Project is a masterpiece of Bachelor degree undergraduate of the Mechanical Engeneering at University of Technology in Brno and in general points out the basic problems associated with constructional plan of the forming machine for flexible pipe production. The Project contains the preview of production of the pipes and problems with designing the machine mainly the forming wheels draft
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Production of sleeper screw
Bartošek, Filip ; Štroner, Marek (referee) ; Lidmila, Zdeněk (advisor)
Bachelor thesis developed in the bachelor degrees addresses technological process of the production sleeper screw. The production uses technology volume thermoforming. The project was elaborated in cooperation with the company ŠROUBÁRNA KYJOV s.r.o. The screw will be made from material ČSN 11 503. This material is unalloyed construction steel with property of weld. Based on the literature study technology volume thermoforming was chosen tamping in closed instrument for the production of head screw. For the production of screw-thread was chosen technology of rolling. For the production head of screw was chosen horizontal fitting press machine. After the production there were used surfacing by galvanic zinc coating because of the better corrosion resistance.
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Production of seamless rings by technology radial-axial rolling
Zapletalová, Martina ; Lidmila, Zdeněk (referee) ; Podaný, Kamil (advisor)
The thesis is focused on the production of a seamless ring manufactured from low-alloyed steel 15 142, which fills the function as a large-dimensional bearing. On the basis of suitable production technologies analysis, the radial axial rolling method was chosen and a specific manufacturing process was proposed. During the manufacturing time, the creation of the forging defects in the transfers forms were occurred, which was totally undesirable. By changing the parameters of the machine, in particular the rolling curve and the temperature, the process was optimized and the production performed completely without defects.
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The role of lubricants in sheet metal forming
Čvanda, Petr ; Novotný, Karel (referee) ; Peterková, Eva (advisor)
This project which was elaborated in the bachelor education present summary of lubricants in technology of forming. Annotation was based on belles-lettres of problematic of these lubricants in technology of forming and include individual sorts of lubricants and their applications in variety of forming operations
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HEAT – MECHANICAL DEGRADATION OF SURFACES AT THE HIGH TEMPERATURES
Zahradník, Radek ; Hajduk, Daniel (referee) ; Čecho, Ladislav (referee) ; Toman,, Zdeněk (referee) ; Raudenský, Miroslav (advisor)
The Ph.D. thesis is focused on a surface degradation mechanisms under combined heat and mechanical load. The objects of examination are work rolls from hot rolling mill which suffer such a load. In first chapter, the hot rolling process, the design, the manufacturing process and present materials of work rolls are described. The state-of-the-art study of work roll surface degradation mechanisms – wear, oxidation, thermal and contact fatigue are described in the second chapter. The characterization, the formation, the mechanisms of progression and the effects of each surface degradation mechanism is described step by step. The state-of-the-art study of analytical and numerical models which are related to hot rolling process is described in third chapter together with their limitations and flaws. The next chapters contain design of an analytical, an optimized macroscopic and a microscopic model for study of the work roll stress state. The macroscopic and the microscopic model is based on finite element method and they are implemented in ANSYS Programming Design Language. The models are used to process several case study which are based on previous experimental work of the Heat transfer and fluid flow laboratory. The results from case studies specify and expand the knowledge of work roll stress state. The results show the portion of each loading factor on the whole stress state. In addition, time and depth depended distribution of stress state is presented. The results from macrosferic model illustrate the cause of spalling and a rupture of the work roll. The results from the microsferic model show the cause of creation of the to-surface-parallel cracks within carbides of high chromium irons. Last chapter summarized of all results gathered from case studies together with the goals for further research definition. The necessary steps for further cognition are stated. The thesis contains a large set of appendixes with deeper discussion of several related topics. These appendixes represent the one third of whole the thesis.
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Boundary Conditions in the Roll Gap during Hot and Cold Rolling
Luks, Tomáš ; Pernis,, Rudolf (referee) ; Hajduk, Daniel (referee) ; Horský, Jaroslav (advisor)
Boundary conditions in the roll gap play an important role in modelling of rolling processes. In the roll gap we can observe the following: changes of rolling pressure, changes of relative velocity, influences of oxides and lubrication, etc. When taking into account all conditions mentioned above the determination of the boundary conditions is not trivial and extensive measurements are necessary. Therefore, this thesis is dealing with design of temperature and force sensors specified for the determination of friction coefficient and heat transfer coefficient in contact. The temperature sensor with an installed thermocouple measures subsurface temperature for a given depth; and then the inverse heat conduction task is used to compute temperature and heat flux on the surface. Several temperature sensors were designed and used for measuring in pilot mill and industrial rolling mill as well. The thermal responses of different sensors were compared in the numerical simulations. The inverse calculations were tested for various rolling conditions. A durability of the sensors was also studied in industrial rolling conditions. The contact stresses in the roll gap were measured by a pin, which was in direct contact with the rolled material. The forces on the top of the pin were measured by a three-axes piezoelectric force transducer and recalculated to the contact stress and friction coefficient. The sensor was implemented in a work roll and tested when rolling aluminium and steel slab for different rolling conditions. The results were compared with the integrative force sensor ROLLSURF.
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Lubricants for forming technologies
Tollrian, Zdeněk ; Císařová, Michaela (referee) ; Šlais, Miroslav (advisor)
This thesis deals with the lubricants used in metal forming technology. Requirements for lubricant, grease and selection process of forming the necessary information to determine the desired properties of the lubricant. The thesis presents an overview of lubricants that are used in various forming processes, their distribution and use. In each chapter the types of lubricants that are used in engineering practice.
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