Wyniki wyszukiwania - Biblioteka Nauki

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Rozwój uszkodzeń wewnętrznych w stalach chromowo-molibdenowych do zastosowań w energetyce konwencjonalnej

100%

Sroka M.

Stal, Metale & Nowe Technologie

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2020

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tom nr 1-2

62--68

PL

W artykule pokazano możliwość zastosowania metod metalograficznych do oceny stopnia uszkodzenia wewnętrznego stali chromowo-molibdenowych eksploatowanych w warunkach pełzania. Wykorzystanie obrazów struktur metalograficznych uzyskanych w wyniku badań w skaningowym mikroskopie elektronowym lub w mikroskopie konfokalnym pozwala zaklasyfikować materiał pod względem stopnia uszkodzenia wewnętrznego. Stanowi ono jedno z istotnych kryteriów dopuszczenia elementu do dalszej eksploatacji lub też podstawę do wymiany elementu instalacji ze względu na zbyt duże jego zniszczenie w wyniku równoczesnego działania podwyższonej temperatury i naprężenia.

EN

The article presents the possibility of using metallographic methods to assess the degree of internal damage to chromium-molybdenum steels operated in creep conditions. Using images of metallographic structures obtained as a result of scanning electron microscopy or confocal microscopy enables classifying a material in terms of the internal damage degree. It is one of the important criteria for approving an element for further operation or is the basis for replacing the element of an installation due to its excessive destruction as a result of the simultaneous action of elevated temperature and stress.

2

Rola Amerykańskiego Stowarzyszenia Bibliotekarzy (ALA) w odbudowie zbiorów bibliotecznych w Polsce i Czechosłowacji w latach 1945–1948

100%

Sroka M.

Biuletyn Biblioteki Jagiellońskiej

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2017

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tom 67

389-404

EN

The role of the American Library Association (ALA) in the post-war restoration of Polish and Czechoslovak library collections is still relatively unknown. This article discusses the ALA assistance program – organized in collaboration with the Rockefeller Foundation – whose aim was to help those libraries which had suffered during the Second World War. It concerned scientific journals and books published in the United States between 1939 and 1946. Selected titles were sent to libraries and research institutes in 31 countries, including Poland and Czechoslovakia. Special attention was given to individual requests received by the ALA from Polish and Czechoslovak librarians, scholars and students.

PL

Tematyka udziału Amerykańskiego Stowarzyszenia Bibliotekarzy (ALA) w powojennej odbudowie zbiorów bibliotecznych w Polsce i Czechosłowacji pozostaje mało znana. Niniejszy artykuł zajmuje się programem pomocy dla bibliotek dotkniętych działaniami wojennymi, który ALA zorganizowało we współpracy z Fundacją Rockefellera. Program zajmował się dwoma rodzajami wydawnictw: czasopismami naukowymi oraz książkami opublikowanymi w Stanach Zjednoczonych w latach 1939–1946. Wybrane tytuły zostały wysłane do placówek naukowych i bibliotek w 31 krajach, w tym Polski i Czechosłowacji. Szczególną uwagę poświęcono indywidualnym prośbom o amerykańskie książki i czasopisma naukowe, które ALA otrzymywało od polskich i czechosłowackich bibliotekarzy, naukowców i studentów.

3

Mechanical properties of Super 304H steel after long-term ageing at 650 and 700°C

51%

Zieliński A. , Sroka M. , Purzyńska H. , Novy F.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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tom Vol. 71, nr 2

art. no. e144612

EN

The paper shows the degradation process of the modern austenitic Super 304H (X10CrNiCuNb18-9-3) steel which was subjected to long-term aging for up to 50,000 h at 650 and 700°C. The investigations include microstructure examination (SEM), identification and analysis of the precipitation process, and mechanical properties tests. The Super 304H steel has a structure characteristic of austenitic steels with visible annealing twins and single primary NbX precipitates. Long-term aging in the steel leads to numerous precipitation processes of M23C6, MX carbides, σ phase, Z phase, and ε-Cu phase. Precipitation processes lead to a decrease in plastic properties and impact energy as well as alloy over aging. Yield strength and tensile strength values after 50,000 h of aging were similar to those as delivered. The yield and tensile strength value strongly depend on the applied aging temperature.

4

Problemy adaptacyjne zabudowań pałacowych na przykładzie budynku kordegardy w Bojadłach

51%

Sroka M. , Urbańska K. , Urbański P.

Materiały Budowlane

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2022

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tom nr 11

195--197

PL

Adaptacja budynku zabytkowego zobowiązuje projektanta do bardzo starannego przygotowania dokumentacji remontowej. Projektowane nowe funkcje nie mogą niszczyć zabytkowych detali, charakteru obiektu lub wnętrza. W artykule przedstawiono problemy adaptacyjne zabytkowego budynku kordegardy w barokowym zespole pałacowo-parkowym zlokalizowanym w Bojadłach. Nowa funkcja budynku ma być dostosowana do wymagań dotyczących pomieszczeń przeznaczonych na cele mieszkalne z zachowaniem historycznego charakteru budynku.

EN

Adaptation of a historic building obliges the designer to very carefully prepare renovation documentation. Designed new functions may not destroy the historic details, character of building or interior space. The article presents the problems of adaptation of the historic guardhouse in the baroque palace and park complex located in Bojadla. The new function of the building will be adapted to the requirements of rooms intended for residential purposes, while maintaining the historical character of the building.

5

Analysis of the precipitation process of secondary phases after long-term ageing of the S304H steel

51%

Zieliński A. , Wersta R. , Sroka M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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tom Vol. 69, nr 5

art. no. e137520

EN

S304H steel is used in the construction of pressure components of boilers with supercritical operating parameters. The paper presents the results of research on the microstructure following ageing for 30,000 hours at 650 and 700°C. Microstructure examination was performed using scanning and transmission electron microscopy. The precipitates were identified using transmission electron microscopy. The paper analyses the precipitation process and its dynamics depending on the temperature and ageing time in detail. MX carbonitrides and the ε_Cu phase were proved to be the most stable phase, regardless of the test temperature. It was also showed that the M₂₃C₆ carbide precipitates in the tested steel and the intermetallic sigma phase (σ) may play a significant role in the loss of durability of the tested steel. This is related to their significant increase due to the influence of elevated temperature, and their coagulation and coalescence dynamics strongly depend on the ageing/operating temperature level. The qualitative and quantitative identification of the secondary phase precipitation processes described in the study is important in the analysis of the loss of durability of the tested steel under creep conditions.

6

The study of the evolution of the microstructure and creep properties of Super 304H austenitic stainless steel after aging for up to 50,000 h

51%

Zieliński A. , Wersta R. , Sroka M.

Archives of Civil and Mechanical Engineering

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2022

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tom Vol. 22, no. 2

art. no. e89, 1--24

EN

The paper discusses several aspects of degradation of Super 304H steel subjected to long-term aging up to 50,000 h at 650 and 750°C. The study includes microstructure examination by scanning and transmission electron microscopy along with X-ray microanalysis of a wide range of precipitates. The Super 304H steel has a structure characteristic for austenitic steels with annealing twins and single primary NBX precipitates of various sizes. Long-term aging leads to precipitation of several phases such as M23C6, MX carbides, σ phases, Z phase and ε-Cu phase. The precipitation processes lead to changes in the creep strength of the tested steel, the value of which strongly depends on the aging temperature used, which is measurably shown by the creep tests carried out with the elongation measured during the test.

7

Structure of 22Cr25NiWCoCu Austenitic Stainless Steel After Ageing

45%

Sroka M. , Zieliński A. , Puszczało T. , Sówka K. , Hadzima B.

Archives of Metallurgy and Materials

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2022

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tom Vol. 67, iss. 1

175--180

EN

The 22Cr25NiWCoCu austenitic stainless steel was developed by AB Sandvik Material Technology in Sweden. Due to its high creep strength and good corrosion resistance, this material is well suited for use in superheaters in advanced coal-fired power boilers as well as in other types of steam boilers using various types of fuel. The examined material was subject to long-term ageing for the time of annealing up to 20 000 h at 700 and 750°C. Precipitation processes and microstructure stability as-received and after ageing were investigated. Examination of the microstructure was conducted using scanning electron microscopy. The identification of secondary phases was carried out by X-ray phase composition. Using the results of the investigations of precipitation processes in the microstructure, both within the grains and at the grain boundaries, their statistical analysis was carried out. To illustrate this impact, the following parameters were used: surface area and equivalent diameter of precipitates. Based on the surface area measurements, the percentage of the phase in the reviewed photo’s total area was calculated.

8

Structure of the S304H Steel after 20,000 Hours of Ageing

45%

Wersta R. , Zieliński A. , Sroka M. , Puszczało T. , Sówka K.

Archives of Metallurgy and Materials

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2022

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tom Vol. 67, iss. 2

487--493

EN

The S304H steel is used in the construction of pressure components of boilers with supercritical operating parameters. The paper presents the results of the research on the microstructure after ageing for 20,000 hours at 650 and 700°C. The microstructure examination was performed using scanning and transmission electron microscopy. The precipitates were identifies using transmission electron microscopy. The influence of ageing time on microstructure changes and the precipitation process of the tested steel is described. The presented research results are an element of material characteristics of the new generation of steel, which are used in the design work of pressure devices of steam boilers and in diagnostic work during operation.

9

Microstructure and Properties of Dissimilar Joints of AISI 430 Steel with Inconel 625 Obtained by Electron Beam Welding

45%

Dziekońska M. , Jonda E. , Sroka M. , Węglowski M. S. , Jung T.

Advances in Science and Technology. Research Journal

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2022

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tom Vol. 16, no 4

232--242

EN

Electron Beam Welding (EBM) is a high-energy density fusion process where joint is bombarded to be welded with strongly focused beam of electrons. This method is often used for advanced materials and complex, critical parts, like turbine rotors, but it can also be used for many simpler processes involving large production runs. It is very suitable for butt welding materials of different thicknesses. The aim of this work was to study the microstructure, hardness, and electrochemical corrosion behavior between the dissimilar welds were investigated. Electron Beam Welding of dissimilar steel alloys Inconel 625 and AISI 430 was studied. In welding process there was used only welded materials without filling material. Results showed the microstructure of the weld solidified in dendritic morphology. The microstructure of fusion zone showed that dendrites grew in different directions for each grain. The dendrites and columnar grains are mainly exposed to the fusion boundary with some equiaxed grains. The hardness of the overall joint was non-uniform. The highest hardness of the HAZ/Inconel 625 (the heat-affected zone) was 258 HV, and the lowest weld zone hardness was 178 HV. The decrease in weld hardness may be due to the linear welding energy, which led to grain growth and excessive cooling. HAZ/AISI 430 steel has the lowest current density and the highest corrosion potential. Steel has a more negative corrosion potential and a lower corrosion current density than joints, likely due to higher levels of chromium. In this study, a metallographic investigation of the joints revealed no defects such as microcracks or pores. The melting temperatures of the two materials were quite different, but with the help of gravity, stainless steel acts as a permanent joint, like a rivet.

10

Możliwość prognozowania stanu procesów wydzieleniowych w stalach austenitycznych

38%

Golański G. , Klimaszewska K. , Purzyńska H. , Zieliński A. , Sroka M. , Pawlyta M.

Energetyka

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2023

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tom nr 11

649--650

PL

Procesy wydzieleniowe w żarowytrzymałych stalach austenitycznych są głównym mechanizmem degradacji ich mikrostruktury i właściwości użytkowych. Przewidywanie składu fazowego wydzieleń za pomocą wykresów czas – temperatura – wydzielanie, może być pomocne przy oszacowaniu czasu bezpiecznej eksploatacji elementów wykonanych z tych materiałów.

EN

Precipitation processes in creep-resisting austenitic steels constitute the main mechanism of degradation of their microstructure and functional properties. Predicting the phase composition of precipitates using the time-temperature-precipitation curve can be helpful for the estimation of safe service time for elements made of these materials.

11

Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia

38%

Razim N. L. , Sheng F. T. S. , Karim A. R. A. , Nabialek M. , Abdullah M. M. A. B. , Sroka M.

Archives of Civil Engineering

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2022

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tom Vol. 68, nr 3

323--338

EN

Steel-wood-steel connection is widely seen in many applications, such as timber structures. The stiffness of steel-wood-steel connection loaded parallel to grain for softwoods originated from Malaysia was investigated in this study. Numerical models have been developed in ABAQUS to study the stiffness connection. Softwoods of Damar Minyak and Podo have been selected in this analysis. The comprehensive study focused on the effect of bolt configurations on stiffness. Numerical analysis is carried out and the developed model has been validated with the previous study. Further investigations have been made by using the validated model. From this model, numerical analysis of the stiffness values have been made for various bolt configurations, including bolt diameter, end distance, bolt spacing, number of rows and bolts and edge distance. The result shows that the stiffness of bolted timber connections for softwood depends on the bolt diameter, number of rows and bolts, end distance and edge distance. Based on the result, stiffness increased as the diameter of the bolt, end distance, number of rows and bolts and edge distance increased. It is also discovered that the stiffness equation in Eurocode 5 (EC5) is inadequate as the equation only considered parameters which are wood density and bolt diameter. Other connection parameters such as geometry are not considered in the EC5 equation.

12

Properties of stone mastic asphalt incorporating nano titanium as binder’s modifier

32%

Zali N. S. S. M. , Masri K. A. , Jaya R. P. , Abdullah M. M. A. B. , Hasan M. , Hasan M. R. M. , Jeż B. , Nabiałek M. , Sroka M. , Pietrusiewicz P.

Archives of Civil Engineering

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2022

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tom Vol. 68, nr 1

653--666

EN

Stone mastic asphalt is a gap-graded mix and is usually related to its high bitumen content and its skeleton-like constitution. Although famous for its durability, high resistance to fatigue and rutting, issues such as bleeding and premature aging do occur in the mix since it has a high bitumen content and voids due to its gap-graded structure. In order to encounter these problems from affecting the mix, some instances such as adding additives, rejuvenators and stabilizers into the mixture has been implemented. Nowadays, nano materials are being used in the asphalt mixtures and nano titanium is being introduced as a modifier to the asphalt binder in order to improve the mechanical properties of the stone mastic asphalt mix. The related tests done in order to access the improvement are resilient modulus, dynamic creep, moisture susceptibility and binder drain down. The content of nano titanium used in this research are 1%, 2%, 3%, 4% and 5%. This study is done to assess the mechanical performance of stone mastic asphalt with nano titanium modified binder.