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Wyszukujesz frazę "degradation of microstructure" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Assessment of Microstructure and Mechanical Properties of the Slag Ladle after Exploitation
Autorzy:
Kalandyk, Barbara
Zapała, Renata
Sobula, Sebastian
Tęcza, Grzegorz
Piotrowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/2049657.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
slag pots
cast steel
mechanical properties
degradation of microstructure
Opis:
The results of tests and examinations of the microstructure and mechanical properties of cast steel used for large-size slag ladles are presented. Castings of this type (especially large-size ladles with a capacity of up to 16 m3) operate under very demanding conditions resulting from the repeated cycles of filling and emptying the ladle with liquid slag at a temperature exceeding even 1600°C. The changes in operating temperature cause faster degradation and wear of slag ladle castings, mainly due to thermal fatigue.The tests carried out on samples taken from different parts/areas of the ladle (flange, bottom and half-height) showed significant differences in the microstructure of the flange and bottom part as compared to the microstructure obtained at half-height of the ladle wall. The flange and bottom were characterized by a ferritic-pearlitic microstructure, while the microstructure at the ladle half-height consisted of a ferritic matrix, cementite and graphite precipitates. Changes in microstructure affected the mechanical properties. Based on the test results it was found that both the flange and the bottom of the ladle had higher mechanical properties, i.e. UTS, YS, hardness, and impact energy than the centre of the ladle wall. Fractography showed the mixed character of fractures with the predominance of brittle fracture. Microporosity and clusters of non-metallic inclusions were also found in the fractures of samples characterized by low properties.
Źródło:
Archives of Metallurgy and Materials; 2021, 66, 2; 351-358
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Microstructure and Degree of Degradation of ZnO Varistors in Surge Arresters Due to Operation
Autorzy:
Papliński, P.
Wańkowicz, J.
Ranachowski, P.
Ranachowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/356415.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surge arrester
MO varistor
microstructure of ceramics
ceramic material degradation
Opis:
The paper presents the test results for the microstructure of ZnO varistors comprising high voltage gapless surge arresters. The tests were performed on varistors produced in different periods and by various manufacturers. The research was inspired by different characteristics of changes in values of current flowing through surge arresters as a function of changes in values of system voltage in a 220 kV substation, and the temperature in a multi-year cycle. Furthermore, the effects of varistor microstructure degradation following a failure of an unsealed surge arrester were investigated. The results provided the grounds for assessment of ZnO varistor microstructure parameters in terms of their durability and resistance to degradation processes.
Źródło:
Archives of Metallurgy and Materials; 2018, 63, 3; 1267-1273
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Microstructure of ZnO Varistors Taken From Surge Arrester Counters
Autorzy:
Papliński, P.
Wańkowicz, J.
Ranachowski, P.
Ranachowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/355223.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surge arrester counter
ZnO varistors
microstructure of ceramics
ceramic material degradation
Opis:
The paper presents investigations of microstructure of varistors of damaged surge arrester counters. A similar ZnO varistor, not subjected before to operation, was a point of reference in this research. The results of investigations of the ZnO varistors show an untypical phase composition of their material, which was characterized by unsatisfying homogeneity and cohesion. The degradation processes of varistor material in the subsequent stages were recognized and described. A harmful impact of humidity inside the untight surge arrester counter on its operation and its ZnO varistors was proved. Some conclusions being the result of the operation checking of surge arrester counters were presented too.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 191-196
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Studies on Degradation of Varistors Subjected to Operation in Surge Arresters and Surge Arrester Counters
Autorzy:
Papliński, P.
Wańkowicz, J.
Śmietanka, H.
Ranachowski, P.
Ranachowski, Z.
Kudela, S. jr.
Aleksiejuk, M.
Powiązania:
https://bibliotekanauki.pl/articles/351611.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
surge arrester
surge arrester counter
MO varistor
microstructure of ceramics
ceramic material degradation
Opis:
The paper presents results of investigation of microstructure and micro-hardness for material of ZnO varistors applied to 110 kV surge arrester and surge arrester counter. The research combined two pairs of varistors, each consisted of one varistor subjected before to operation, while the other one was brand new unit and constituted a reference. All varistors were made of the same material by the reputable manufacture. The tests revealed a different degree of the material degradation for varistors subjected before to operation. This also refers to different degradation mechanism observed for the material of these varistors, if typical effects of degradation of aged ZnO varistors were considered as a reference. Physical state of spinel in the microstructure had a significant impact on the material degradation, however a considerable loosening of the microstructure associated with bismuth oxide was observed too. It was surprising, since the precipitates of the bismuth oxide phase most often showed very good binding to the ZnO matrix and high resistance to associated electrical, thermal and mechanical effects. The degradation effects in the ZnO matrix proved to be limited only.
Źródło:
Archives of Metallurgy and Materials; 2020, 65, 1; 367-374
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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