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1

Przemiany fazowe zachodzące w układach Fe/NH3/H2 oraz Fe-N

Michalski Jerzy, Frączek Tadeusz

Inżynieria Powierzchni

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2021

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nr 1

5--13

PL

W artykule omówiono na podstawie literatury przemiany fazowe w azotkach żelaza wytworzonych na proszkach żelaza i na próbkach litych. Przedstawiono przemiany fazowe podczas wyżarzania w atmosferze NH3/H2 oraz w atmosferach obojętnych. Wskazano podobieństwo przemian fazowych w różnych atmosferach zastosowanych podczas wyżarzania. Opisano warunki przemian fazowych w azotkach żelaza podczas wyżarzania w atmosferze NH3/H2, w argonie oraz próżni. Przemiany fazowe zachodzące podczas wyżarzania w atmosferze NH3/H2 są odwracalne, występuje w nich zjawisko histerezy. Podczas przemiany fazowej ɛ→γ’ w atmosferze NH3/H2 do momentu zakończenia przemiany ma miejsce emisja azotu do atmosfery. Natomiast niezbędnym warunkiem przebiegu przemiany γ’→ɛ jest strumień azotu z atmosfery do powierzchni. Przemiany fazowe podczas wygrzewania w próżni i argonie są nieodwracalne. Podczas ciągłego ogrzewania azotowanych proszków żelaza z szybkością 30 K/min w próżni i argonie mogą wystąpić dwie przemiany fazowe, którym nie towarzyszy ubytek masy. Pierwsza, (α+γ’)→γN w zakresie temperatur 540÷550°C w próżni i 620÷630°C w argonie oraz druga, (γ+γ’)→ɛ w zakresie 610÷620°C w próżni i 690÷710°C w argonie. W przypadku nagrzewania w argonie początek ubytku masy rejestrowano w temperaturze ok. 860°C, natomiast w próżni kończy się w tej temperaturze odazotowanie austenitu azotowego γN. Podczas wyżarzania w temperaturze 360ºC przemianie fazowej ɛ→γ’ w warstwie ɛ/γ’ towarzyszy wzrost grubości fazy γ’, który odbywa się kosztem grubości strefy ɛ, przy czym całkowita grubość warstwy po przemianie jest taka sama, jak jej grubość w stanie wyjściowym. W temperaturze 420ºC po zakończonej przemianie ɛ→γ’, utworzona monofazowa warstwa γ’ jest grubsza od warstw ɛ/γ’ w stanie wyjściowym.

EN

In the article, based on the literature, the phase changes in iron nitrides on iron powders and on solid samples were discussed. Phase transformations in NH3/H2 atmosphere and in inert atmospheres are discussed. The similarity of phase transformations in different atmospheres used during annealing were indicated. The conditions of phase transformations in iron nitrides during annealing in NH3/H2 atmosphere, argon and vacuum were discussed. Phase transformations occurring during annealing in the NH3/H2 atmosphere are reversible and there is a hysteresis phenomenon. During the phase transformation ɛ→γ' in the NH3/H2 atmosphere until the transformation is completed, nitrogen emission to the atmosphere takes place. On the other hand, the condition for the course of the transformation of γ'→ɛ is the nitrogen flow from the atmosphere to the surface. Phase changes during heating in vacuum and argon are irreversible. During continuous heating at a rate of 30 K / min in vacuum and argon, nitrided iron powders, two phase transformations may occur, which are not accompanied by weight loss, the first (α+γ') →γN in the temperature range 540÷550°C in a vacuum and 620÷630°C in argon and the second (γ+γ') →ɛ in the range of 610÷620°C in vacuum and 690÷710°C in argon. In the case of heating in argon, the onset of weight loss was recorded at a temperature of about 860°C. Whereas in vacuum the denitration of nitrogen austenite γN ends at this temperature. During annealing at the temperature of 360°C, the phase change ɛ→γ′ in the ɛ/γ′ layer is accompanied by an increase in the thickness of the γ′ phase, which is at the expense of the thickness of the ɛ zone, while the total thickness of the layer after the transformation is the same as its initial thickness. At the temperature of 420°C, after the completion of the γ′ transformation, the formed monophasic layer γ′ is thicker than the ɛ/γ′ layers in the initial state.

2

Profit optimization for multi-mode repetitive construction project with cash flows using metaheuristics

Sroka Bartłomiej, Rosłon Jerzy, Podolski Michał, Bożejko Wojciech, Burduk Anna, Wodecki Mieczysław

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

441--457

EN

The article presents the profit optimization model for multi-unit construction projects. Such projects constitute a special case of repetitive projects and are common in residential, commercial, and industrial construction projects. Due to the specific character of construction works, schedules of such projects should take into account many different aspects, including durations and costs of construction works, the possibility of selecting alternative execution modes, and specific restrictions (e.g., deadlines for the completion of units imposed by the investor). To solve the NP-hard problem of choosing the order of units’ construction and the best variants of works, the authors used metaheuristic algorithms (simulated annealing and genetic search). The objective function in the presented optimization model was the total profit of the contractor determined on the basis of the mathematical programming model. This model takes into account monthly cash flows subject to direct and indirect costs, penalties for missing deadlines, costs of work group discontinuities, and borrowing losses. The presented problem is very important for maintaining a good financial condition of the enterprise carrying out construction projects. In the article, an experimental analysis of the proposed method of solving the optimization task was carried out in a model that showed high efficiency in obtaining suboptimal solutions. In addition, the operation of the proposed model has been presented on a calculation example. The results obtained in it are fully satisfying.

3

Phase transformations in the nitrided layer during annealing under reduced pressure

Frączek Tadeusz, Michalski Jerzy, Kucharska Barbara, Opydo Michał, Ogórek Marzena

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

146--156

EN

The article presents studies of phase transformations taking place in surface layers of nitrided steels as a result of their annealing at 520 °C for 5 and 10 h. Two steel grades were tested, the unalloyed AISI 1085 and the low-alloy AISI 52100. As a result of glow discharge nitriding, at 570 °C/5 h and 540 °C/12 h, respectively, nitrided layers were produced on the steels, consisting of a surface layer of iron nitrides with the structure of ε + γ′ and γ′ and of similar thickness 25. The study showed that during 5 h of annealing at 520 °C, the iron nitride layer already decomposed, which was documented by the analysis of chemical composition and X-ray analysis of the surface layers of steel. Comparative studies on the hardness distribution of surface layers of nitrided as well as nitrided and subsequently annealed AISI 52100 steels showed that after both 5 and 10 h of annealing, the hardness depth profiles were very similar and the effective thickness of the diffusion layer did not change. The results obtained enabled the demonstration that the emission of nitrogen into the atmosphere during annealing of nitrided steels is not accompanied by diffusion of nitrogen into the base layer. This proves that the iron nitride layer is not a source of nitrogen for the diffusion layer during annealing at reduced pressure.

4

The affinity for dialysate species of thermally modified titania nanotubes under static and dynamic conditions

Jędrzejewska Aleksandra, Pasik Kamila, Nycz Marta, Arkusz Katarzyna

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 4

95--105

EN

Purpose: During the dialysis process, hemolysis is the most frequently occurring problem to solve. Titanium dioxide nanotubes (TNTs) can be considered as a material preventing hemodialysis or blood species deposition thanks to their unique properties, i.e., hydrophilicity, smooth surface, and antibacterial. The purpose of this work was the electrochemical, chemical, and morphological characteristics of the TNTs and the evaluation of the possibility of using them as filter parts in dialysis techniques. Methods: The tests were carried out on as-formed TNTs with a diameter of 50 ± 5 nm and 1000 ± 100 nm in height, and TNTs thermally modified in air atmosphere temperatures ranging from 350 to 550 °C. Electrochemical and microscopic analyses were performed both in the static and dynamic system of dialysis fluid (flow rate: 250 cm3/min). Additionally, deposition or damage of blood cells was specified during the ex vivo dialysis experiment. Results: Obtained results proved relationship between electrochemical properties of TNTs and the method of their modification. The results demonstrated that the TNTs annealed at 450 °C TNTs can be potentially applied for constructions dialysis membrane in the hemodialysis area due to their most stable stationary potential in dialysate, the highest value of impedance modulus, and the most favourable electrokinetic properties. Additionally, it was confirmed that annealed process causes improvement of corrosion resistance and protective properties for TNTs in the dialysis fluid. Conclusions: The result allowed for the conclusion that annealing is responsible for reduction of adsorption properties of TNTs, though this titanium dioxide nanotube still can be used as filter part in haemodialysis.

5

Deformation-induced martensite in austenitic stainless steels: A review

Sohrabi Mohammad Javad, Naghizadeh Meysam, Mirzadeh Hamed

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

382--405

EN

Recent progress in the understanding of the deformation-induced martensitic transformation, the transformation-induced plasticity (TRIP) effect, and the reversion annealing in the metastable austenitic stainless steels are reviewed in the present work. For this purpose, the introduced methods for the measurement of martensite content are summarized. Moreover, the austenite stability as the key factor for controlling the austenite to martensite transformation is critically discussed. This is realized by analyzing the effects of chemical composition, initial grain size, applied strain, deformation temperature, strain rate, and deformation mode (stress state). For instance, the effect of initial grain size is found to be complicated, especially in the ultrafine grained (UFG) regime. Furthermore, it seems that there is a critical grain size for changing the trend of α′-martensite formation. Decreasing the deformation temperature motivates the formation of α′-martensite, but there is a critical temperature for achieving the maximum tensile ductility. Afterwards, the modeling techniques for the transformation kinetics and the contribution of deformation-induced martensitic transformation to the strengthening of material and also strength-ductility trade-off are critically surveyed. The processing of UFG microstructure during reversion annealing, the effects of the recrystallization of the retained austenite, the martensitic shear and diffusional reversion mechanisms, and the annealing-induced martensitic transformation are also summarized. Accordingly, this overview presents the opportunities that the strain-induced martensitic transformation can offer for controlling the microstructure and mechanical properties of metastable austenitic stainless steels.

6

A review of recent progress in mechanical and corrosion properties of dual phase steels

Kalhor Alireza, Soleimani Maryam, Mirzadeh Hamed, Uthaisangsuk Vitoon

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

309--322

EN

New concepts proposed for processing of dual phase (DP) steels as one of the main classes of advanced high-strength steels (AHSSs) to enhance their mechanical properties (strength–ductility combination) and corrosion resistance were introduced. The current review covers (I) the processing routes to obtain the ferritic–martensitic microstructures, (II) parameters of intercritical annealing (IA) treatment, (III) primary thermomechanical treatments, and (IV) post processing. First, the principal heat treatment methods, i.e., step quenching, intermediate quenching, and intercritical annealing of ferritic–pearlitic steel, as well as the partitioning of manganese were critically discussed. Then, the effects of holding time at the intercritical annealing temperature on the austenitization, grain coarsening kinetics, abnormal grain growth, and volume fraction of martensite were summarized. Next, the importance of cold deformation (notably rolling) and heating rate for the development of fine-grained DP microstructures (with chain-networked martensitic islands) through recrystallization and modification of the preferred nucleation sites for the austenite phase was discussed. Moreover, the applications of severe plastic deformation techniques (such as constrained groove pressing), thermal cycling (multi-step or repetitive intercritical annealing), and spheroidization heat treatment were discussed. Finally, the impacts of tempering, quench aging, and bake hardening on the properties of DP steel were reviewed. This short overview shows the opportunities that the conventional and innovative processing routes can offer for the potential industrial applications of DP steels, especially in the lightweight car body for the automotive industry to address the safety, fuel consumption, and air pollution issues.

7

Influence of geometry and annealing temperature in argon atmosphere of TiO2 nanotubes on their electrochemical properties

Nycz Marta, Paradowska Ewa, Arkusz Katarzyna, Pijanowska Dorota Genowefa

Acta of Bioengineering and Biomechanics

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2020

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Vol. 22, no. 1

165--177

EN

In this paper, electrochemical properties of the as-formed and thermally treated titanium dioxide (TiO2) nanotubes with diameter in the range of 20–100 nm and height in the range of 100–1000 nm were presented. In addition, the effects of annealing temperature (450–550 °C) on the electrochemical characteristics of these structures, as well as the influence of diameter and height of TiO2 nanotubes on these properties were examined. The results were referred to a compact TiO2 layer (100 nm thick). Methods: The electrochemical test included open circuit potential, impedance spectroscopy and cyclic voltammetry measurements. The scanning electron microscope with energy dispersive spectroscopy analyser, x-ray photoelectron spectroscopy, and x-ray diffraction analysers were used for surface morphology characterisation as well as elemental, phase and chemical composition of TiO2 layers. Results: It was found that nanotubes with the diameter of 50 and 75 nm (height of 1000 nm) annealed at 550 °C exhibit the lowest impedance and phase angle values. However, the voltammetric detection of potassium ferricyanide indicated that the closest to 1 Ipc /Ipa ratio were shown by nanotubes with a diameter of 50 and 75 nm annealed at 450 °C. Conclusions: On the basis of performed analysis, it can be stated that the TiO2 layer with nanotubes of 50 nm in diameter and of 1000 nm in height, annealed in 450 °C may be indicated as the ones having the most favourable sensing and biosensing properties.

8

The effect of annealing and anisotropic behaviour on tensile and fatigue properties of AA 8090

Abass M. H., Mahmud F., Alali M. S., Abood A. N.

Archives of Materials Science and Engineering

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2019

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Vol. 99, nr 1/2

5--12

EN

Purpose: This paper aims to assess microstructures and mechanical properties of annealed and un-annealed Al-Li alloys (AA8090) and provide valid information regarding influence of anisotropy on tensile properties, fatigue lives. Design/methodology/approach: The methodology included investigating the influence of annealing on grain size, tensile strength and fatigue lives of AA8090. Optical microscope, scanning electron microscope and X-ray diffraction were utilized to analyse the crystallographic texture. Findings: The results showed that the un-annealed alloy exhibited much finer grain structure in three directions, namely longitudinal (L) rolling direction, L-45° and Long transverse (LT) combined with stronger crystallographic texture. Regarding to mechanical properties, un-annealed alloy presented superior tensile strength with strong anisotropic behaviour. L and LT grains direction showed highest tensile strength value of 550 MPa and L-45° showed lowest tensile strength value of 420 MPa. Results of fatigue test revealed that annealed Al-Li alloy has lower fatigue lives with high influence of test direction on fatigue properties. Higher variation in fatigue life to failure links with un-annealed alloy over annealed alloy. Examination of fractured surface showed that the morphology of fractured surface is a mixture of ductile and brittle fractures in both annealed and un-annealed alloys with more brittle behaviour in un-annealed alloy. Research limitations/implications: The main challenge of this work is the determination of the test direction (test angle in respect to rolling direction), which is necessary to provide correct information regarding mechanical properties. Further study of low cycle fatigue can be done in future, which will be an excellent indication to mechanical properties of this alloy since it provides more understanding to the behaviour of the material and better comprehend crack propagation and strain stress concentration. Practical implications: AA8090 alloy is an important candidate for aerospace and aircraft industries. Influence of annealing heat treatment and rolling direction on mechanical properties of AA8090 alloy provides more accurate information to the manufacturers who deal with this alloy. Originality/value: This study is affording a significant information regarding the effect of annealing and anisotropic behaviour on mechanical properties of AA8090. To our knowledge, there are few reports that study this combination of factors on AA8090 alloy.

9

The Influence of Lamellar Graphite Cast Iron Annealing on Hardness and Structure

Roučka J., Prochazka J., Kana V., Krutis V., Nedelova K.

Archives of Foundry Engineering

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2019

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iss. 4

105--112

EN

An analysis has been carried out of the influence of annealing time at the preheating temperature of 650 °C on the change in hardness and alloy structure of lamellar graphite cast iron in the working as well as in the laboratory conditions. This preheat temperature is common during reclaiming welding of castings with complex shapes. The changes in unalloyed cast iron EN-GJL 200 to EN-GJL 300 according to ISO 1690 standard and cast iron with low amount of elements such as Sn, Cu, Cr, and Mo and their combinations were assessed. It was found that the cast iron of higher strength grades has better hardness and structural stability. Cast iron alloyed with chromium or its combinations has the highest stability. In unalloyed cast iron, a partial degradation of pearlite occurs; in alloyed cast iron the structural changes are not conclusive.

10

Soft-Sensing in Batch Annealing Based on Finite Differential Method and Support Vector Regression

Kačur Ján, Durdán Milan, Laciak Marek, Flegner Patrik

Advances in Science and Technology. Research Journal

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2019

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Vol. 13, no 4

70--86

EN

The temperature of annealed steel coils is a determining variable of the future steel sheets quality. This variable also determines the energy consumption in operation. Unfortunately, the monitoring of coil inner temperature is problematic due to the furnace environment with high temperature, coil structure, and annealing principle. Currently, there are no measuring principles that can measure the temperature inside the heat-treated product in a non-destructive manner. In this paper, the soft sensing of inner temperature based on the theory of non-stationary heat conduction and approach based on Support Vector Regression (SVR) was presented. The results showed that a black-box approach based on the SVR could replace an analytic approach, though with lesser performance. Several annealing experiments were performed to create a training data set and model performance improvement in the estimation of inner coil temperatures. The proposed software based on non-stationary heat conduction can calculate the behavior of inner coil temperature from the measured boundary temperatures that are measured by thermocouples. The soft-sensing principles presented in this paper were verified under laboratory conditions and on the data obtained from a real annealing plant.

11

Mechaniczne i strukturalne aspekty szybkiej krystalizacji wybranych stopów aluminium

Błaż L., Kula A.

Obróbka Plastyczna Metali

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2018

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T. 29, nr 1

33--64

PL

W przeglądowej formie przedstawiono wyniki dotychczasowych badań szybkokrystalizowanych stopów aluminium, które wykonano w latach 1999–2016 w ramach współpracy naukowo-badawczej Wydziału Metali Nieżelaznych AGH i Nihon University w Tokio. Zastosowanie rozpylania ciekłego stopu na powierzchnię intensywnie chłodzonego walca miedzianego pozwoliło uzyskać cienkie płatki metaliczne, które następnie konsolidowano mechanicznie w procesie prasowania, odgazowania próżniowego i wyciskania. Badano materiały zawierające dodatki stopowe takie, jak Si, Mn, Fe, Ni, Co oraz typowy skład dla wybranych stopów serii 7000 (Mezo10 i Mezo20). Wyróżniono trzy grupy materiałów różniących się trwałością efektu rozdrobnienia składników strukturalnych po szybkiej rekrystalizacji. W warunkach wyżarzania w podwyższonej temperaturze najbardziej stabilne wydzielenia (Si) stwierdzono w stopach RS Al-Si. Stopy RS zawierające metale przejściowe takie, jak Fe, Ni, Mn, Co charakteryzują się umiarkowanie stabilną morfologią wydzieleń, które ulegają bardzo powolnej koagulacji w wysokiej temperaturze, lecz nie osiągają rozmiarów typowych dla materiałów wytwarzanych w technologiach przemysłowych. Stwierdzono, że szybka krystalizacja wymienionych stopów znacząco zwiększa nie tylko własności wytrzymałościowe, ale również plastyczność powyższych stopów. Do trzeciej grupy szybko-krystalizowanych materiałów należą wyroby ze stopów serii 2000, 6000, 7000, które w technologiach przemysłowych poddaje się umocnieniu w procesie starzenia. Pokazano przy-kłady badań strukturalnych i mechanicznych stopów Mezo10 i Mezo20 (seria 7000). Materiały RS wykonane z tych stopów charakteryzują się obecnością wydzieleń o wymiarach 0,5–1,5 µm zawierających podstawowe dodatki stopowe Zn, Mg, Mn. Obecność tych wydzieleń wynika z procesu szybkiej krystalizacji, który nadaje cechy struktury odmienne od przewidywanych zgodnie z wykresem równowagi termodynamicznej.

EN

This review presents the results of studies on rapidly-solidified (RS) aluminum alloys that have been performed during the years 1999-2016 as part of scientific and research cooperation program between the Faculty of Non-ferrous Metals at AGH and Nihon University in Tokyo. The application of liquid alloy spraying onto the intensively cooled and rotating copper cylinder made it possible to obtain thin metallic flakes, which were then consolidated mechanically in the process of pressing, vacuum degasification and extrusion. Materials containing alloying elements such as Si, Mn, Fe, Ni, Co, and selected AA7000series alloys (Mezo10 and Mezo20) were studied. Three groups of materials were distinguished, differing in the persistence of the refinement effect on structural components following rapid recrystallization. Under annealing conditions at elevated temperature, the most stable precipitates (Si) were observed in RS Al-Si alloys. RS alloys containing transitional metals such as Fe, Ni, Mn and Co are characterized by a moderately stable morphology of precipitates, which undergo very slow coarsening at high temperature but do not reach the sizes typical for materials manufactured by industrial technologies. It was found that rapid crystallization of the aforementioned alloys significantly in-creases not only their strength properties but also their plasticity. The third group of rapidly-solidified materials include products made of 2000-, 6000- and 7000-series alloys, which are usually hardened by means of aging process in industrial technologies. Examples of structural and mechanical tests conducted on the Mezo10 and Mezo20 (7000-serie alloys) are shown. RS materials made from these alloys are characterized by the presence of precipitates with sizes of 0.5-1.5 µm, containing basic alloying elements, i.e. Zn, Mg, Mn. The presence of these precipitates arises from the rapid crystallization process, which bestows structural features different from those expected according to the thermo-dynamic equilibrium (phase) diagram.

12

Annealing effect on microstructure and chemical composition of Inconel 625 alloy

Petrzak P., Kowalski K., Rozmus-Górnikowska M., Dębowska A., Jędrusik M., Koclęga D.

Metallurgy and Foundry Engineering

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2018

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Vol. 44, no. 2

73--80

EN

Our research focused on Inconel 625 weld overlays on 16Mo3 steel boiler pipes. The investigation focused on the characterization of changes in the microstructure and chemical composition after annealing. The annealing was performed for ten hours at temperatures from 600 to 1000°C. Changes in the microstructure were observed with a scanning and transmission electron microscope (SEM and TEM). The investigation was supplemented by hardness measurements.

PL

Badania przeprowadzono na napoinach ze stopu Inconel 625 na stali kotłowej 16Mo3. Skoncentrowano się na charakterystyce mikrostruktury i składu chemicznego zmian po wyżarzaniu. Obróbkę cieplną przeprowadzono w temperaturze od 600 do 1000°C przez 10 godzin. Zmiany mikrostruktury obserwowano przy użyciu skaningowej i transmisyjnej mikroskopii elektronowej (SEM i TEM). Badania zostały uzupełnione o pomiary twardości.

13

Electrically driven thermal annealing set-up dedicated to high quality factor optical resonator fabrication

Salzenstein P., Diallo S., Zarubin M.

Journal of Power Technologies

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2018

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Vol. 98, nr 2

198--201

EN

This paper reports on the development of an oven with a special purpose electronic board and specialist materials such as basalt fiber and nichrome. It is designed for optical resonators which are temperature controlled during their annealing process to increase their quality factor for the purpose of photonics applications.

14

Wpływ procesu wyżarzania wyrobów ze stopów magnezu serii AZ na ich własności mechaniczne

Płonka B., Korczak P., Remsak K., Bieda-Niemiec M.

Rudy i Metale Nieżelazne Recykling

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2017

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R. 62, nr 12

42--46

PL

Artykuł dotyczy badań zrealizowanych na stopach AZ31 i AZ61. Materiały te zostały wytworzone w IMN OML Skawina w postaci wlewków o średnicach 102 mm. Następnie w procesie przeciwbieżnego wyciskania wytworzono z nich rury. Określono strukturę wyjściową i własności mechaniczne w podstawowych stanach obróbki cieplnej. Kolejnym etapem było poddanie wyrobów wyciskanych wyżarzaniu w temperaturach od 100 do 450°C, w celu określenia możliwości podniesienia plastyczności badanych stopów, aby umożliwić ich kształtowanie na zimno. W wyniku wyżarzania obniżono twardość stopów z ~60HB do ~40HB. Do końcowych badań wytypowano temperaturę wyżarzania 400°C, dla której przy nieznacznym spadku własności wytrzymałościowych, uzyskano dla badanych stopów wzrost wydłużenia A10 z ok. 10 do 20%. Pozwoliło to na kształtowanie rur ze stopów magnezu na zimno w procesie gięcia, uzyskując kąt gięcia powyżej 90°.

EN

The paper presents investigations conducted on AZ31 and AZ61 magnesium alloys. Material for test were casted Ø102 mm billets made IMN OML Skawina. From those billets tubes were extruded in indirect mode. After extrusion process both structural and mechanical tests have been done. Next step was heat treatment of extruded tubes in the range of 100–450°C to determine the possibility to improve their workability in cold bending process. As a result the hardness of the material decreased from ~60HB to ~40HB. For final tests annealing temperature has been set to 400°C what has resulted in significant increase of plastic elongation (from A10 = 10% to more than A10 = 20%) with inconsiderable decrease of mechanical properties. Consequently the possibility of tubes cold bending has been achieved with bending angle above 90°.

15

Structure and properties of hot-rolled and annealed AZ61 magnesium alloy

Sułkowski B.

Metallurgy and Foundry Engineering

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2017

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Vol. 43, no. 1

21--29

EN

Magnesium alloy AZ61 was processed by hot rolling up to a large thickness reduction (~89%) in several routes with intermediate annealing. The hot rolling process was conducted at 450°C and at a 1.5 s−1 strain rate. The structure and texture evolution as well as the mechanical properties during processing were investigated. The structure studies showed that, during the hot-rolling process, a large number of twins formed, which had an impact on the mechanical properties of the hot-rolled samples. After annealing for 15 minutes, the twins were no longer observed in the annealed samples, causing a significant decrease in hardness. Moreover, an investigation of the hardness showed that annealing for 15 minutes did not remove all of the hardening effects nor did the hardness of the annealed samples decrease to the value before hot rolling. The texture investigations showed that the texture of the hot-rolled samples was a typical basal-type texture. However, the basal pick was split into two tilted towards the rolling direction (RD). The texture changed during annealing while the new strong texture components evolved. The annealing led to an increased intensity of <1010>{1120} texture component and enhanced ductility. It was concluded that the texture changes observed in the present investigations may lead to the enhanced ductility of magnesium alloys and, therefore, help us design a deformation scheme for magnesium alloys consisting of several thermomechanical routes.

PL

Stop magnezu AZ61 został odkształcony przez walcowanie na gorąco do sumarycznego zgniotu 89%, w kilku przepustach z wyżarzaniem międzyoperacyjnym. Walcowanie odbywało się w temperaturze 450°C, a prędkość odkształcenia wynosiła 1,5 s−1. W pracy badano wpływ struktury oraz tekstury na własności mechaniczne stopu AZ61. Badania strukturalne pokazały występowanie dużej liczby bliźniaków po walcowaniu na gorąco, co miało wpływ na własności mechaniczne. Po wyżarzaniu przez 15 minut struktura nie zawierała bliźniaków oraz zaobserwowano spadek własności mechanicznych badanych próbek, ale nie do wartości sprzed walcowania. Z kolei badania teksturowe wykazały, że po walcowaniu na gorąco powstaje tekstura typu bazalnego, z dwoma pikami odchylonymi od [0001] w kierunku walcowania. Po wyżarzaniu zaobserwowano dodatkowy komponent tekstury, <1010>{1120}, co spowodowało poprawę własności plastycznych badanego materiału. Zaobserwowane zmiany strukturalne i teksturowe wpływają silnie na własności plastyczne stopu AZ61, dzięki czemu możliwe jest odpowiednie zaprojektowanie procesu walcowania tego materiału.

16

Wpływ wyżarzania na mikrostrukturę i właściwości blach walcowanych na zimno ze stali X60MnAl30-9

Woźniak D., Kuc D., Bednarczyk I., Żak A.

Hutnik, Wiadomości Hutnicze

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2017

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Vol. 84, nr 8

394--396

PL

Celem pracy było ustalenie optymalnych parametrów wyżarzania rekrystalizującego dla blach walcowanych na zimno wykonanych ze stali X60MnAl30-9. Badana stal odznacza się wysoką wytrzymałością i ciągliwością, zaś z uwagi na dodatek 9%Al spełnia kryterium tzw. „lekkiej stali” Mikrostruktura oraz właściwości blach zależą w głównej mierze od parametrów temperatury i czasu wyżarzania, który w procesach ciągłych powinien być możliwie najkrótszy. Badania mikrostruktury oraz właściwości mechanicznych dla dobranych parametrów umożliwiły dobór optymalnych parametrów procesu dla uzyskania optymalnej relacji właściwości wytrzymałościowych do plastycznych.

EN

The aim of the paper was to determine the parameters of recrystallization annealing for cold-rolled sheets prepared from steel X60MnAl30- 9. Tested steel is characterized with high resistance and ductility but due to the addition of 9%Al it meets the criterion of the so-called “light steel”. Microstructure and properties of metal sheets are mainly dependent on temperature and time of annealing which in continuous processes should be as short as possible. Tests of microstructure and mechanical properties for given parameters enabled the choice of the optimum parameters of the process to achieve the best possible relation of the resistance properties and the plastic properties.

17

Wpływ obróbki cieplno-plastycznej na właściwości mechaniczne stali wysokomanganowej

Perzyński G.

Hutnik, Wiadomości Hutnicze

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2017

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Vol. 84, nr 8

391--393

PL

Zrealizowano próby walcowania na zimno stali w gatunku X60MnAl20-3 z dodatkiem wanadu, uzyskując blachę o grubości 1mm. Umocnioną blachę poddano zabiegowi wyżarzania rekrystalizującego. Określono właściwości mechaniczne oraz mikrostrukturę walcowanej stali. Wykonano próby tłoczności metoda Errichsena. Przeprowadzone badania ułatwią dobór parametrów procesu, pozwalających na uzyskanie optymalnych właściwości wyrobu końcowego.

EN

Cold rolling process of steel X60MnAl20-3with vanadium added has been realised, obtaining a sheet thickness of 1mm. The reinforced sheet was subjected to recrystallization annealing. Mechanical properties and microstructure of rolled steel were determined. Errichsen method was performed. The research will make it easier to select the process parameters to achieve the optimum properties of the final product.

18

Prognozowanie średnicy wydzieleń w warunkach niestabilności mikrostruktury stali VM12-SHC

Zieliński A., Miczka M.

Prace Instytutu Metalurgii Żelaza

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2016

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T. 68, nr 4

2--7

PL

Przeprowadzono badania mikrostruktury stali VM12-SHC w stanie wyjściowym oraz po 30 000 godzin wyżarzania w temperaturze 600 i 650°C. Dla reprezentatywnych obrazów mikrostruktury przeprowadzono analizę ilościową wydzieleń. Wykonano analizę statystyczną zebranych danych, celem oszacowania parametrów wybranego, teoretycznego rozkładu statystycznego. Obliczono prognozę średniej średnicy wydzieleń i odchylenia standardowego takiego rozkładu dla czasu równego 50 000 godzin w temperaturze 600 i 650°C. Uzyskane wyniki badań potwierdzają możliwość zastosowania, w ocenie stopnia degradacji eksploatowanych materiałów, metod prognozowania wywodzących się ze statystyki matematycznej, a w szczególności teorii procesów stochastycznych oraz metod prognozowania przez analogię. Przedstawiono procedurę, która pozwala na opracowanie prognozy gęstości prawdopodobieństwa średnicy wydzieleń w warunkach niestabilności mikrostruktury wybranego gatunku stali.

EN

The microstructure of the VM12-SHC steel in initial state and after 30 000 hours of heating at a temperature of 600 and 650°C was investigated. In order to obtain representative images of microstructure, quantitative analysis of precipitations was carried out. Statistical analysis of the collected data was carried out in order to estimate the parameters of the selected, theoretical statistical distribution. Forecast of the average diameter of precipitations and standard deviation of such distribution was calculated for 50 000 hours at a temperature of 600 and 650°C. The obtained test results con&rm the possibility to use, for the assessment of the level of degradation of used materials, forecasting methods originating from mathematical statistics, in particular theory of stochastic processes and forecast by analogy. A procedure that allows to establish the forecast for probability density of the diameter of precipitations under instability of microstructure of a selected steel grade was presented.

19

Characterisation of TCP phases in CMSX-4 single crystal superalloy subjected to high temperature annealing and creep deformation

Dubiel B., Indyka P., Kruk A., Kalemba-Rec I., Moskalewicz T., Berent K., Gajewska M.

Inżynieria Materiałowa

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2016

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Vol. 37, nr 4

150--155

EN

A high temperature exposure of nickel-base single crystal superalloys leads to a formation of topologically close packed (TCP) phases, what can deteriorate their creep strength. Therefore, the aim of the present work was to investigate TCP phases precipitated in CMSX-4 superalloy after a two-step treatment consisting of annealing at temperature of 1100°C followed by a creep deformation at temperature of 900°C. The microstructure of CMSX-4 superalloy exposed to a high temperature was investigated by means of scanning and transmission electron microscopy as well as scanning-transmission electron microscopy in high angle annular dark field mode. The chemical composition in nanoareas was determined using the high spatial resolution and high count rate energy dispersive X-ray spectroscopy. A three-dimensional characterization of the microstructure of annealed and creep tested single crystal superalloy was carried out by means of electron tomography. Results of microstructural investigation have shown that after the application of two-step high temperature exposure the TCP precipitates present in CMSX-4 superalloy are P and μ phases. The most pronounced differences in the chemical composition of the investigated P and μ phase particles are concerned with W and Re content. It was determined that the P phase contains a higher amount of W, while the μ phase is mostly rich in Re.

PL

Monokrystaliczne nadstopy niklu to nowoczesne materiały żarowytrzymałe, zaprojektowane specjalnie do zastosowania na łopatki turbin gazowych. Skład chemiczny tych stopów jest tak dobrany, aby w mikrostrukturze uzyskać około 70% udziału objętościowego wydzieleń fazy γʹ o kształcie sześciennym oraz umocnienie roztworowe osnowy γ. Silny efekt umocnienia zapewniają pierwiastki o dużym promieniu atomowym, takie jak Re, W i Mo, które wolno dyfundują w osnowie Ni. Jednak po długotrwałej pracy w wysokiej temperaturze pierwiastki te sprzyjają wydzielaniu kruchych faz o strukturze topologicznie zwarcie wypełnionej (topologically close packed, TCP). Najczęściej spotykanymi fazami TCP w nadstopach monokrystalicznych są fazy σ, μ, P i R. Ze względu na niewielkie różnice parametrów sieci oraz składu chemicznego identyfikacja tych faz jest skomplikowana i wymaga połączenia komplementarnych technik dyfrakcji elektronów i mikroanalizy składu chemicznego. Celem pracy jest identyfikacja faz TCP w monokrystalicznym nadstopie niklu CMSX-4 po wysokotemperaturowym wyżarzaniu i pełzaniu, określenie ich składu chemicznego oraz kształtu i rozmieszczenia w przestrzeni z wykorzystaniem nowoczesnych metod analitycznej mikroskopii elektronowej i tomografii elektronowej.

20

Effect of the Annealing Temperature on the Microstructure and Properties of Ausferritic Nodular Cast Iron

Gumienny G., Klimek L., Kurowska B.

Archives of Foundry Engineering

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2016

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Vol. 16, iss. 3

43--48

EN

The paper presents the microstructure and selected properties of ausferritic nodular cast iron annealed at the temperature 520 and 550°C. This choice was dictated by the temperatures used in the practice of nitriding. Nodular graphite in cast iron was obtained with use of Inmold process. Cast iron containing molybdenum and copper ensuring obtaining an ausferrite in the cast iron matrix without the use of heat treatment of castings was tested. The effect of annealing temperature on the microstructure and the kind of fracture of the ausferritic nodular cast iron was presented. The effect of an annealing temperature on hardness, impact strength and the microhardness of ausferritic nodular cast iron matrix was shown too. The lamellar structure of phases in the cast iron matrix after annealing has been ascertained. There has been an increase in hardness of an annealed cast iron and microhardness of its matrix. The reduction in the impact strength of the cast iron annealed at 520 and 550°C was approximately 10-30%. Both an increase in the hardness of cast iron as well as an decrease in its impact strength is probably due to the separation of secondary carbides during the heat treatment.