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Růst krátkých trhlin ve feriticko-perliticko-bainitické oceli
Polák, Jaroslav
The initiation and the growth of short cracks were studied in ferritic-pearlitic-bainitic steel. Short cracks initiate preferably in persistent slip markings in areas of proeutectoid ferrite. The kinetics of short crack growth is characterized by exponential growth. Crack growth coefficient was found to be a function of plastic strain amplitude. The comparison of the short crack growth kinetics with Coffin-Manson law allows determining the parameters of the short crack growth law from the low cycle fatigue experiments
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Magnetic local measurement of state of thermal refined steel
Skrbek, B. ; Tomáš, Ivan
Magnetic methods application (coercitive force measurement, magnetic induction, MAT, magnetic spot method) investigation of steel structure in the world and Czech Republic. New knowledge of magnetic spot method for application on steels. Principle of magnetic spot method. Results comparison obtained on machined, non-heat-treated, heat-treated and corroded surface. Determination of boundary application conditions. Particular results at appropriation of hardness checking of hardened and tempered sheets and forgings at hardening shop. Recommendation.
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The redistribution of carbon and manganese in weldments of manganese steels
Král, Lubomír ; Zlámal, B. ; Million, Bořivoj
In this paper, the results of diffusion C and Mn measurements in diffusion couples in steels with content of manganese in range 0-15 wt.% are discussed. The diffusion and thermodynamics characteristics were evaluated by using stationary model (SM). The ratio n does not agree with condition of quasistationary model (QSM) n=2 for solution of diffusion in these diffusion couples. In the paper, the results of carbon redistribution for n=2 a n= 2,8-3,7 for diffusion couples shown above are confronted each other. The part of this paper attend to more detailed description of structure changes on weldments interface in diffusion couples 0.28C-0.04Mn/0.31C- 5.01Mn a 0.28C-0.04Mn/0.34C-15.04Mn (wt.%).
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LONG-TIME OXIDATION OF .gamma.Fe AND LH15 STEEL AT HIGH TEMPERATURES IN AIR
Kučera, Jaroslav ; Adamaszek, K. ; Jurasz, Z.
The investigation of long-time oxidation of gFe and of low alloyed steel LH15 in ambient air is reported. The specimens of gFe had the form of wires with diameter f = 3.0 mm. The relative weight gain Dw/w of these specimens grows in the course of oxidation anneal due to the oxides FeO, Fe3O4, Fe2O3 formation. The weight gain is stopped at very long time period t of oxidation anneals. This phenomenon is denoted as saturation effect. The same effect was observed in the case of oxidation of specimens made from low alloyed steel LH15. The specimens had the form of cylinders with diameter .fi. = 10 mm.
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Steel industry in the european region.
David, Tomáš ; Kašpar, Václav (advisor) ; Vošta, Milan (referee)
The topic of this diploma thesis is "Steel industry in european region". It is divided into four main parts. The first part is concerning the history of smelting industry, its general characteristics on worldwide basis and organizational structure associating the companies of steel industry. The second part is following the situation of steel industry in the european region and specifically in its most important regions. Next part is focusing on the worldwide situation on steel market, actual fininacial crisis and the consequnces and impact of these factors on the status of european smelting industry. The last part is describing the process of the merger of one of the world largest steel companies, concerns Arcelor and Mittal Steel in 2006, preceding circumstances and results of this incorporation. At the end I am trying to outline the perspectives of steel industry in nearest future and summarizing the knowledge acquired during writing this diploma thesis.
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Finanční analýza Moravia steel a.s.
Fertaľová, Zuzana ; Kopalová, Helena (advisor) ; Metzlová, Hana (referee)
Nižší podiel výsledku hospodárenia ku základnému kapitálu v roku 2001 zapríčinili kurzové rozdiely, ktoré spôsobili zníženie pridanej hodnoty a provozného hospodárskeho výsledku. Naopak v roku 2004 bol výsledok hospodárenia podielovo najvyšší, tento rok môžeme charakterizovať ako najúspešnejší v hospodárení firmy. Výroba v odvetví napredovala z celosvetového hľadiska. Vyrobená oceľ po prvýkrát v histórii dosiahla hranice jednej miliardy ton, čo predstavovalo 8,8 % celosvetovej produkcie ocele. Zároveň bol rok 2004 rokom vstupu Českej republiky do Európskej Únie, a z toho vyplývala rada podstatných zmien. Konkrétne bola jednou z nich reorganizácia predaja, ktorá viedla k zjednodušeniu a sprehľadneniu vzťahov so zákazníkmi. K pozitívnym zmenám došlo aj v oblasti logistiky a dopravy, firme sa tak podarilo napĺňať stratégiu ? Just In Time? .
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