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1
Możliwość prognozowania stanu procesów wydzieleniowych w stalach austenitycznych
Golański Grzegorz, Klimaszewska Klaudia, Purzyńska Hanna, Zieliński Adam, Sroka Marek, Pawlyta Mirosława
Energetyka
|
2023
|
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.
2
Content available Mechanical properties of Super 304H steel after long-term ageing at 650 and 700°C
Zieliński Adam, Sroka Marek, Purzyńska Hanna, Novy Frantisek
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2023
|
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.
3
Content available remote Problemy adaptacyjne zabudowań pałacowych na przykładzie budynku kordegardy w Bojadłach
Sroka Marek, Urbańska Krystyna, Urbański Paweł
Materiały Budowlane
|
2022
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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.
4
Content available Structure of the S304H Steel after 20,000 Hours of Ageing
Wersta Robert, Zieliński Adam, Sroka Marek, Puszczało Tomasz, Sówka Karol
Archives of Metallurgy and Materials
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2022
|
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.
5
Content available Structure of 22Cr25NiWCoCu Austenitic Stainless Steel After Ageing
Sroka Marek, Zieliński A., Puszczało T., Sówka K., Hadzima B.
Archives of Metallurgy and Materials
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2022
|
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.
6
Content available Properties of stone mastic asphalt incorporating nano titanium as binder’s modifier
Zali Nur Syafiqah Shamimi Mohd, Masri Khairil Azman, Jaya Ramadhansyah Putra, Abdullah Mohd Mustafa Al Bakri, Hasan Muzamir, Hasan Mohd Rosli Mohd, Jeż Bartłomiej, Nabiałek Marcin, Sroka Marek, Pietrusiewicz Paweł
Archives of Civil Engineering
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2022
|
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.
7
Content available Effect of bolt configurations on stiffness for steel-wood-steel connection loaded parallel to grain for softwoods in Malaysia
Razim Nur Liza, Sheng Francis Ting Shyue, Karim Abdul Razak Abdul, Nabialek Marcin, Abdullah Mohd Mustafa Al Bakri, Sroka Marek
Archives of Civil Engineering
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2022
|
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.
8
Content available remote 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
Zieliński A., Wersta R., Sroka Marek
Archives of Civil and Mechanical Engineering
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2022
|
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.
9
Content available Microstructure and Properties of Dissimilar Joints of AISI 430 Steel with Inconel 625 Obtained by Electron Beam Welding
Dziekońska Małgorzata, Jonda Ewa, Sroka Marek, Węglowski Marek Stanisław, Jung Tymoteusz
Advances in Science and Technology. Research Journal
|
2022
|
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
Content available Analysis of the precipitation process of secondary phases after long-term ageing of the S304H steel
Zieliński Adam, Wersta Robert, Sroka Marek
Bulletin of the Polish Academy of Sciences. Technical Sciences
|
2021
|
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.
11
Content available remote Rozwój uszkodzeń wewnętrznych w stalach chromowo-molibdenowych do zastosowań w energetyce konwencjonalnej
Sroka Marek
Stal, Metale & Nowe Technologie
|
2020
|
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.
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