Browsing by Subject "scale"

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Access status: Restricted ,
Analiza wpływu deniwelacji terenu na niejednorodność skali pionowego zdjęcia lotniczego
(Data obrony: 2013-01-19) Markowicz, Anna
Wydział Geodezji Górniczej i Inżynierii Środowiska
Access status: Open Access ,
Development and verification of the scale growth model during high temperature oxidation for S235 steel
(Wydawnictwa AGH, 2020) Przyłucka, Aleksandra; Cebo-Rudnicka, Agnieszka; Rywotycki, Marcin; Augustyn-Nadzieja, Joanna; Malinowski, Zbigniew
Every year rapid industrialization and the following urbanization fuel the global demand for steel. The use of steel products contributes to the sustainable development of society. The scale growth mechanism accompanies the high-temperature plastic working of metals and alloys. The article focuses on the thickness of the scale formed as a result of annealing steel samples in a furnace. Samples made of S235 (A283C) steel were heated at two temperatures, 1100°C and 1200°C, for 8 minutes. The amount of scale formed was determined on the basis of photos taken with a light microscope. The transformed equations of steel oxidation kinetics were used in the computational part. The scale thickness obtained numerically corresponded to the scale formed in real conditions. The aim of the research was to adjust the scale growth model on steel so that it gives correct results in relation to the actual thickness of the formed oxidized layer.
Access status: Open Access ,
Scaling behaviour of Si-alloyed steel slabs under reheating conditions
(AGH University of Science and Technology Press, 2021) Mikl, Gregor; Höfler, Thomas; Gierl-Mayer, Christian; Danninger, Herbert; Linder, Bernhard; Angeli, Gerhard
Reheating of steel slabs for further processing such as hot rolling usually takes place in gas-fired pusher furnaces. Temperatures well above 1000°C, combined with an atmosphere containing $H_{2}O$, $CO_{2}$, and $O_{2}$, lead to substantial oxidation of most steel grades. Newly developed advanced steels often contain significant amounts of Si. This element plays a dominant role in the scaling behaviour near the steel-scale-interface, since fayalite $(Fe_{2}SiO_{4})$ forms a eutectic with wuestite $(Fe_{1-x}O)$ that melts as low as 1177°C. To better understand the high temperature oxidation behaviour, lab-scale trials were performed with different steel grades containing up to 3 wt.% Si. Possible interactions of Si with other alloying elements present in the samples such as Cr, Mn and Al were also of interest. The atmosphere contained 20% $H_{2}O$, 7% $CO_{2}$, and 3% $O_{2}$, resembling reheating conditions in pusher furnaces, and temperatures ranged from 1100 to 1240°C. For metallographic investigation, the oxidised samples were cold mounted under vacuum using taper section angles. After preparation, the sections were examined through light microscopy, SEM/EDS, XRD, and TEM. The local distribution of the alloying elements could be mapped efficiently, and phase identification was successful in most parts. Under the applied experimental conditions, the elements of interest were present in their oxidic form either as pure or as mixed oxides. Higher Si-contents led to an increased build-up of eutectic melting phase at the steel-scale-interface at temperatures above 1177°C, which in turn further accelerated the oxidation.