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1

Zmiany struktury i własności mechanicznych w stalach i staliwach eksploatowanych w podwyższonych temperaturach

Stachura Stefania

Energetyka

|

2022

|

nr 3

158--164

2

The role of institute of ferrous metallurgy in the development of materials for the power industry

Zieliński Adam

Journal of Metallic Materials

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2021

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Vol. 73, no. 1

3--8

EN

The article presents an outline of the development of the domestic energy sector from the very beginning of its operation. It discusses the impact of the research conducted at the Stanisław Staszic Institute of Ferrous Metallurgy in Gliwice on the selection of steel grades for operation at elevated and high temperatures for applications in the Polish power industry. The article presents the research and implementation achievements of the research workers of the Institute with the discussion and the purpose of their creation. The article presents the area of joint scientific and research achievements of the Institute of Ferrous Metallurgy with affiliated domestic and foreign research centres, documented by numerous research projects and publications in renowned scientific journals.

PL

Przedstawiono zarys rozwoju krajowej energetyki od początku jej funkcjonowania. Omówiono wpływ badań prowadzonych w Instytucie Metalurgii Żelaza im. Stanisława Staszica w Gliwicach na dobór gatunków stali do pracy w podwyższonej i wysokiej temperaturze do zastosowań w polskiej energetyce. Zaprezentowano dorobek badawczo-wdrożeniowy pracowników naukowych Instytutu z omówieniem i celowością ich powstania. Przedstawiono obszar wspólnych dokonań naukowo-badawczych Instytutu Metalurgii Żelaza z zaprzyjaźnionymi krajowymi i zagranicznymi ośrodkami badawczymi, udokumentowanymi licznymi projektami badawczymi i publikacjami w renomowanych czasopismach naukowych.

3

Non-wetting to Wetting Transition Temperatures of Liquid Tin on Surfaces of Different Steel Samples Corresponding to their Spontaneous Deoxidation

Varanasi D., Aldawoudi K. E, Baumli P., Koncz-Horvath D., Kaptay G.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 2

469--476

EN

The goal of this paper is to measure the non-wetting to wetting transition temperatures of liquid tin on surfaces of different steel samples in vacuum with residual pressure of 10-8 bar. The experiments were conducted on four steels (C45, S103, CK60 and EN1.4034) of varying compositions using pure tin (99.99%) by the sessile drop method. Non-wetting to wetting transition (contact angle decreasing below 90°) by liquid tin was observed as function of increasing temperature in the range of 820-940 K for low alloyed steels C45, S103 and CK60, while it was considerably higher (around 1130 K) for high chromium EN1.4034 steel. it is concluded that at about the same temperatures, the surfaces of the steel samples are spontaneously deoxidized due to the combined effect of high temperature, low vacuum and C-content of steels. After the oxide layer is removed, the contact angles of liquid tin on steel surfaces were found in the range of 45-80° for low alloyed C45, S103 and CK60 steels and around 20° for high chromium EN1.4034 steel. These relatively high contact angle values compared to other metal/metal couples (such as liquid Cu on steels) are due to the formation of not fully metallic intermetallic compounds (FeSn and FeSn2) at the interface (such do not form in the Cu/Fe system).

4

Advances in Surface Engineering Using TIG Processing to Incorporate Ceramic Particulates into Low Alloy and Microalloyed Steels – A Review

Munoz-Escalona Patricia, Mridha Shahjahan, Baker Thomas Neville

Advances in Science and Technology. Research Journal

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2021

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Vol. 15, no 3

88--98

EN

The application of surface engineering techniques to improve the surface properties of carbon steels using high powered lasers for transformation hardening and surface melting is well established. Based on this previous research, a tungsten inert gas torch (TIG) technique has more recently been explored for the surface modification of steels, as a much cheaper option to lasers. In the present research, initial studies compared the preheat temperature recorded on a low alloy steel with Ar, He and N protective shielding gases over a single track length. The effect of overlapping 17 tracks on the temperature variation for three different gases was also explored. These studies lead to Ar being the chosen gas for the next stages of the work. During TIG processing, incorporation of fine TiC or SiC ceramic particulates into the liquid steel was investigated, with the aim of obtaining a uniformly high hardness in a crack and porous- free melt zone of sufficient length and depth to provide improved wear resistance over the parent steel. TiC particulates of 45-100µm size were preplaced on a low alloy steel, and following TIG processing, the hardness increased from the as-received steel value of ~200 Hv to~800 Hv, due to some dissolution and re-precipitation of TiC particulates. The incorporation of the more economic SiC particulates of ∼5μm or ∼75 μm size preplaced on a microalloyed steel was investigated. Single track surface zones were melted by a tungsten inert gas torch, and the effect of two energy inputs, 420 and 840 Jmm−1, compared. The results showed that the samples melted using 420 Jmm−1 were crack-free. Analytical microstructural and XRD studies established that both sizes of SiC particulates dissolved, and that some of the hardness increase recorded was due to formation of a high carbon martensite. A potential method of decreasing SiC particulate dissolution by generating a high Fe–Si liquid, thereby retaining the ceramic in the microalloyed steel after processing, was found to show promise.

5

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

Sroka Marek

Stal, Metale & Nowe Technologie

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2020

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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.

6

Effect of Thermomechanical Controlled Processing and Quenching & Tempering on the Structure and Properties of Bainite-Martensite Steels

Mandal G., Ghosh S. K., Chatterjee S.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

861--868

EN

In the present time, advanced high strength steel (AHSS) has secured a dominant place in the automobile sector due to its high strength and good toughness along with the reduced weight of car body which results in increased fuel efficiency, controlled emission of greenhouse gases and increased passengers’ safety. In the present study, four new advanced high strength steels (AHSS) have been developed using three different processing routes, i.e., thermomechanical controlled processing (TMCP), quenching treatment (QT ), and quenching & tempering (Q&T) processes, respectively. The current steels have achieved a better combination of the high level of strength with reasonable ductility in case of TMCP as compared to the other processing conditions. The achievable ultrahigh strength is primarily attributed to mixed microstructure comprising lower bainite and lath martensite as well as grain refinement and precipitation hardening.

7

Analiza warunków kształtowania oraz właściwości tiksotropowych stało-ciekłej stali

Sołek Krzysztof

Hutnik, Wiadomości Hutnicze

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2019

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Vol. 86, nr 4

127--132

PL

Procesy kształtowania stopów metali w stanie stało-ciekłym (ang. SSM-Forming – Semi-Solid Metal Forming) są często nazywane od zjawiska tiksotropii, kształtowaniem tiksotropowym (ang. thixoforming). Procesy te posiadają wybrane zalety klasycznych procesów kucia oraz odlewania, co daje im technologiczny oraz ekonomiczny potencjał do produkcji elementów o wysokich własnościach mechanicznych i jednocześnie skomplikowanym kształcie. W artykule omówiono warunki zapewniające poprawny przebieg procesów kształtowania tiksotropowego stopów żelaza. Wśród warunków tych kluczowy jest dobór stali najbardziej nadających się do kształtowania w oparciu o dostępne technologie oraz przygotowanie struktury globularnej, która powoduje zmniejszenie lepkości stali. W celu wykazania wagi zmian w strukturze wykonano pomiary reologiczne, w trakcie których zaobserwowano zjawisko tiksotropii oraz zostały wyznaczone parametry modelu umożliwiającego analizę zmian lepkości spowodowanych tym zjawiskiem dla stali X210Cr12.

EN

Metal forming processes in the semi-solid state (SSM-Forming) are often called, from the phenomenon of thixotropy, thixoforming processes. Many advantages of both classical metal forming and casting techniques characterize thixoforming processes and this is a reason of economical potential of producing elements having high mechanical properties and complicated shapes. The article discusses the conditions that ensure the correct course of the thixoforming of steel alloys. Among these conditions, the selection of the steel alloys, which are the best for thixoforming processes based on available technologies and the preparation of the globular structure, which reduces the viscosity during shaping, are crucial. In order to show the importance of changes in the structure, rheological measurements were made, during which the phenomenon of thixotropy was observed and the parameters of the model enabling the analysis of viscosity changes caused by this phenomenon for X210Cr12 steel were determined.

8

Thixoforming of high-melting-point alloys

Sołek K.

Metallurgy and Foundry Engineering

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2017

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Vol. 43, no. 4

249--268

EN

Processing of steel in the semi-solid state concerns mainly continuous casting and thixoforming processes. Continuous casting is usually applied within the confines of steel making processes. Due to stringent process requirements, thixotropic forming of steel alloys has not been practically applied in industry yet. However, it is believed that this method could be used for forming selected products. Thixoforming could be treated as alternative method of production for forging techniques in the case non-plastic alloys. In this paper the method of development of globular microstructure, thixoforming process and analysis of rheological properties of selected steels were described.

PL

Procesy formowania tiksotropowego stopów aluminium oraz magnezu znajdują zastosowanie w praktyce przemysłowej. Ze stopów aluminium w ten sposób wykonuje się szereg elementów, między innymi na potrzeby przemysłu motoryzacyjnego. Kształtowanie w stanie stałociekłym stopów magnezu jest realizowane z wykorzystaniem technologii nazywanej thixomolding, pozwalającej kształtować elementy produkowane na potrzeby na przykład przemysłu elektronicznego. Procesom formowania tiksotropowego stopów metali wysokotopliwych takich jak stale lub stopy Co-Cr-Ni towarzyszy szereg trudności powodowanych wysoką temperaturą formowania, dlatego tiksoformowanie tych stopów nie znalazło jak dotąd praktycznego zastosowania. Obecnie realizuje się szereg badań naukowych, których celem jest wyeliminowanie trudności technicznych oraz obniżenie kosztów tych procesów. W tej pracy zostały omówione metody rozwoju struktury globularnej, procesy formowania tiksotropowego oraz właściwości reologiczne wybranych stali.

9

Applicability of Friction Stir Welding to steels

Çam G., İpekoğlu G., Küçükömeroğlu T., Aktarer S. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2017

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Vol. 80, nr 2

65--85

EN

Purpose: The friction stir welding (FSW) method is widely considered to be one of the most significant developments in joining technology to emerge in the last 30 years. The technique has originally been developed for joining difficult-to-fusion-weld Al-alloys, particularly for high strength grades and now widely used in various industrial applications, such as transport industries. On the other hand, the application of FSW to high temperature materials such as steels is hindered due to the problems associated with the stirring tools although there is a wide interest for the application of this technique to these materials. Design/methodology/approach: The aim of this review is to address the current state-of-the-art of FSW of steels, focusing particularly on microstructural aspects and the resulting properties of these joints and discuss the future prospects of this technique for steels. For instance, the use of FSW can be advantageous for joining steels in some special applications where conventional fusion welding processes fail to produce sound cost effective joints, and the high tooling costs of FSW can be justified (i.e. underwater joining of steel pipes or hot plate welding in steel mills). In this study, only structural steels (mainly plain C steels), ferritic stainless steels, austenitic stainless steels and duplex stainless steels will be considered and the other types of steels are out of the scope of this work although some examples are included in the discussion. Research limitations/implications: The tools experience high temperatures in FSW of steels, i.e., above 1000°C. The number of tool materials which can withstand such temperatures is very limited. In addition, the welding of many common steels can be readily conducted by various conventional fusion welding methods. These joining methods are very flexible, easy-to-perform and well established in industrial applications, which further prevents the application of FSW to these materials. These limitations are to be overcome for commercial exploitation of this technique for joining steels.

10

Dp_builder : the computer system for the design of the continuous annealing cycles for DP steels

Górecki G., Kuziak R., Kwiaton N., Madej Ł., Pietrzyk M.

Computer Methods in Materials Science

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2015

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Vol. 15, No.3

394--408

EN

The DP_builder software, which was developed to design the best continuous annealing technology for DP steels in a fast and efficient way, is presented in the paper. The key components of the system, including models of phase transformations during heating and cooling stages, are described first. Following this, major principles, features and implementation details of the system are presented. The main functionalities of the system compose simulation of microstructure evolution during thermal cycles and capability to apply simulations to design the best technological variant. Additionally a database, which stores material and technological information for all previously analyzed cases, was designed and incorporated in the system. Finally, graphical user interface was added to make the system easily accessible and user friendly.

PL

Przedstawiona praca opisuje zaprojektowany i zbudowany system, dzięki któremu w prosty sposób można zaprojektować technologię ciągłego wyżarzania stali typu DP (Dual-Phase). W pierwszej części pracy opisano główny moduł systemu wykorzystujący modele przemian fazowych podczas nagrzewania i chłodzenia. Następnie opisano zasady działania, dostępne funkcjonalności oraz szczegóły implementacyjne prezentowanej aplikacji. Główna funkcjonalność systemu łączy w sobie symulację ewolucji mikrostruktury podczas cykli nagrzewania i chłodzenia oraz optymalizację połączoną z procesem projektowania cykli, co daje duża swobodę podczas konfiguracji. Dodatkową funkcjonalnością systemu jest zdolność do przechowywania informacji o materiałach i parametrach technologicznych wszystkich analizowanych do tej pory przypadkach. Aby aplikacja była przejrzysta i łatwa w użytku wyposażono ją również w graficzny interfejs użytkownika.

11

The Effect of Stepped Austempering on Phase Composition and Mechanical Properties of Nanostructured X37CrMoV5-1 Steel

Marciniak S., Skołek E., Świątnicki W.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 1

517--521

EN

This paper presents the results of studies of X37CrMoV5-1 steel subjected to quenching processes with a one-step and a two-step isothermal annealing. The TEM observation revealed that steel after one-step treatment led is composed of carbide-free bainite with nanometric thickness of ferrite plates and of high volume fraction of retained austenite in form of thin layers or large blocks. In order to improve the strength parameters an attempt was made to reduce the austenite content by use of quenching with the two-step isothermal annealing. The temperature and time of each step were designed on the basis of dilatometric measurements. It was shown, that the two-step heat treatment led to increase of the bainitic ferrite content and resulted in improvement of steel's strength with no loss of steel ductility.

PL

W artykule przedstawiono wyniki badań stali X37CrMoV5-1 poddanej hartowaniu izotermicznemu jedno i dwu stopniowemu. Obserwacji TEM wykazały, że stal po jednostopniowym hartowaniu izotermicznym składa się z bainitu bezwęglikowego o nanometrycznej grubości płytek ferrytu poprzedzielanych cienkimi warstwami lub blokami austenitu. Wysoka plastyczność stali wynika z wysokiej zawartością fazy austenitycznej. W celu poprawy parametrów wytrzymałościowych postanowiono zmniejszyć ilość austenitu poprzez zastosowanie dwustopniowego hartowania izotermicznego. Parametry tego procesu zostały zaprojektowane na podstawie badań dylatometrycznych. Wykazano, że dwustopniowa obróbka cieplna prowadził do podwyższenia zawartości ferrytu bainitycznego i tym samym do poprawy wytrzymałości stali bez utraty plastyczności.

12

Calculation of volume fractions of microstructural components in steels cooled from the austenitizing temperature

Trzaska J.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 1

38--44

EN

Purpose: The paper presents method in predicting the volume fractions of ferrite, pearlite, bainite and martensite of steel cooled continuously from the austenitizing temperature, basing on the chemical composition, austenitizing temperature and cooling rate. Design/methodology/approach: In the paper it has been applied a hybrid approach that combined application of various mathematical tools including logistic regression and multiple regression to solve selected tasks from the area of materials science. Findings: Computational methods are an alternative to experimental measurement in providing the material data required for heat treatment process simulation.Research limitations/implications: All equations are limited by range of mass concentrations of elements which is presented in Table 2. Practical implications: The worked out formulae may be used in computer systems of steels’ designing for the heat-treated machine parts. Originality/value: The paper presents the method for calculating the volume fractions of ferrite, pearlite, bainite and martensite of the structural steels, depending on their chemical composition, austenitizing temperature and cooling rate.

13

Relationships for heating depth versus power, diameter and moving velocity of the continuous laser beam. Theory and experiment

Kraposhin V. S.

Inżynieria Materiałowa

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2013

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Vol. 34, nr 5

485--487

EN

Simple engineering relationships have been derived for the dependence of a heating depth z on the combination ofmain continuous heating source parameters, P/(dv)n, where P, d, v stand for a beam power, diameter and moving Velocity respectively. The function z vs P/(dv)n must be linear with n = 0.5 for the one-dimensional heating and n = 0.4 for the three-dimensional heating. Experimental veriﬁcation for these relationships is presented for several steels and cast irons after cw CO2-laser heating. As expected occurs these linear relationships were true for both solid state heating and melting. In some cases the phase composition of steels can be presented as the function of the P/(dv)n parameter. Several conclusions can be established: - the dependence of the quenched layer thickness (both with or without melting) for steels and cast irons on the heat source parameters P, d, v can be described as the linear function of PFon, and the Fourier criterion is deﬁned approximately as a/(dv) and the exponent m = 0.5 or 0.4 for one-dimensional and three-dimensional case respectively; - the linear dependence z vs PF0n' has been experimentally proved for laser and plasma heating ofvarious steels and cast irons.

PL

W artykule została pokazana prosta zależność matematyczna między głębokością nagrzewania z oraz kombinacją głównych parametrów ciągłych żródła ciepła: P/(dv)n, w której P, d, v to odpowiednio moc, średnica i prędkość wiązki. Zależność Z = P/(dv)n ma charakter liniowy przy n = 0,5 dla jednowymiarowego nagrzewania oraz n = 0,4 dla nagrzewania trójwymiarowego. Wykonane eksperymenty potwierdziły tę zależnośćw badaniu wykonanym dla kilku rodzajów stali i żeliw nagrzewanych laserową wiązką CO2. Zgodnie z oczekiwaniami występująca liniowa zależność jest prawdziwa zarówno podczas nagrzewania ciała stałego, jak i warstwy nadtopionej. W niektórych przypadkach także skład fazowy stali może być określony jako funkcja parametrów P/(dv)n. Na podstawie przeprowadzonych badań można sformułować następujące wnioski: - Zależność grubości warstwy zahartowanej (zarówno nadtopionej, jak i nienadtopionej) stali i żeliwa od parametrów źródła ciepła P, d, v została opisana jako funkcja liniowa PFon, gdzie kryterium Fouriera zostało określone w przybliżeniu jako a/(dv) oraz wykładnik m odpowiednio jako równy 0,5 lub 0,4 dla przypadków jednowymiarowego lub trójwymiarowego nagrzewania; - zależność liniowa z = PFon została doświadczalnie wyznaczona dla nagrzewania laserowego i plazmowego dla różnych rodzajów stali i żeliw.

14

The structure of a general materials genome approach to the design of new steel grades for specific properties

Xu W., LU Q., Xu X., van der Zwaag S.

Computer Methods in Materials Science

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2013

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Vol. 13, No. 3

382--394

EN

In this work we review and reformulate a general alloy design methodology based on thermodynamic and kinetic principles, employing the genetic algorithm as the optimization scheme. The new approach relies on two key concepts: the ‘translator’ and the ‘creator’. The ‘translator’ is the conversion of the desired (thermo-)mechanical properties into required microstructures using known microstructure-property relationships. The ‘creator’ translates quantifiable microstructural parameters into metallurgical and economical parameters, i.e. composition, heat treatment parameter and cost, again employing established metallurgical principles. In the case of well defined ‘translator’ and ‘creator’ functions the model allows simultaneous, human intervention free optimization of alloy composition and key heat treatment parameters, i.e., austenitization temperatures and ageing temperatures, so as to fulfill multiple design criteria and eventually to achieve the desired microstructure. The elementary version of the model, not defining the ‘translator’ or ‘creator’ modules explicitly has applied to the design of ultra high strength (UHS) stainless steel and was validated by experiments on prototype alloys. The model was subsequently extended to take into account the alloying cost by adding a cost factor to various alloying elements, and is shown to provide valuable guidelines to the design and modification of alloy compositions and has the capacity to optimize strength and material cost in an integrated manner. In this manuscript the new conceptual approach to alloy design is reformulated in a more generic and abstract manner and new extensions of the model to the design of high temperature resistant steels (both creep steels and fire resistant steels) and abrasion resistant steels are discussed, and some preliminary results are shown.

PL

W pracy omówiono metodę projektowania stopów wykorzystującą zasady termodynamiki i kinetyki i stosując algorytmy genetyczne w procedurze optymalizacyjnej. Metoda polega na zastosowaniu dwóch głównych pojęć: translatora i kreatora. Translator jest zamianą wymaganych własności termomechanicznych na wymaganą mikrostrukturę, wykorzystując znane zależności między tymi parametrami. Kreator stosuje ustalone zasady metalurgiczne i zamienia ilościowe parametry mikrostruktury w parametry metalurgiczne i ekonomiczne, tzn. skład chemiczny, parametry obróbki cieplnej i koszty. W przypadku dobrze zdefiniowanych funkcji translatora i kreatora model pozwala na równoczesną optymalizację, z interwencją człowieka,dla składu chemicznego oraz dla parametrów obróbki cieplnej, tzn temperatury austenityzacji i temperatury starzenia. W ten sposób spełnione są różne kryteria projektowania i ostatecznie uzyskiwana jest wymagana mikrostruktura. Podstawowa wersja modelu, która nie definiuje modułów translatora i kreatora w sposób jawny, została zastosowana do projektowania stali nierdzewnych o podwyższonej wytrzymałości (ang. Ultra High Strength - UHS). Otrzymane wyniki zostały zweryfikowane doświadczalnie. Następnie model został rozszerzony i uwzględniono koszt dodatków stopowych poprzez wprowadzenie czynnika kosztów dla różnych pierwiastków stopowych. W ten sposób uzyskano cenne wskazówki dla projektowania i modyfikacji składu chemicznego i możliwość optymalizacji w sposób zintegrowany wytrzymałości materiału i kosztów jego wytwarzania. W niniejszej pracy to podejście zostało dalej uogólnione i stworzono nowe rozszerzenie modelu dla projektowania stali żaroodpornych, stali odpornych na pełzanie w wysokich temperaturach i stali odpornych na zużycie ścierne. Zamieszczone zostały wstępne wyniki uzyskane z nowej wersji modelu.

15

Computer assisted evaluation of degree of exhaustion of T/P23 (2.25Cr-0.3Mo-1.6W-V-Nb) steel after long-term annealing

Sroka M., Zieliński A.

Archives of Materials Science and Engineering

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2013

|

Vol. 64, nr 2

205--212

EN

Purpose: The method of image analysis and artificial intelligence methods in the evaluation of materials while working in creep conditions were proposed. The application of scanning electron microscopy in the correct assessment of the degree of exhaustion was of a demonstration character. Design/methodology/approach: For the material after long-term operation in the creep tests microstructure examination was performed in a scanning electron microscope. To assess the degree of exhaustion of the material, the computer program was used. Findings: The article demonstrates how to assess the state of the material using a computer program as an example of the application of computer methods for materials science. The verification was found to develop methodologies for assessing the correct level of exhaustion while working in steel material creep conditions. Practical implications: The presented method can be used for evaluation and qualification of structural changes in power station boiler components operating in creep conditions. Originality/value: The obtained results of changes in the mechanical properties, microstructure and in the precipitation processes are applied to the evaluating the condition of the elements in further industrial service.

16

Hybrid modelling methods in materials science - selected examples

Sitek W., Trzaska J.

Journal of Achievements in Materials and Manufacturing Engineering

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2012

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Vol. 54, nr 1

93--102

EN

Purpose: The paper presents selected examples of application of computational tools, including artificial intelligence methods to solve examples of tasks in the area of materials science. (i) Selection method of steel grade with required hardenability; (ii) Modelling of CCT diagrams for engineering and constructional steels; (iii) Application of neural networks for selection of steel with the assumed hardness after cooling from the austenitising temperature; (iv) Designing of high-speed steels chemical composition Design/methodology/approach: In the paper been applied a hybrid approach that combined application of various mathematical tools including artificial neural networks, linear regression and genetic algorithms to solve selected tasks from the area of materials science. Findings: Computer modelling and simulation make improvement of engineering materials properties possible, as well as prediction of their properties, even before the materials are fabricated, with the significant reduction of expenditures and time necessary for their investigation and application. Methods used in hybrid systems are complementary and disadvantages of one method are compensated by the advantages of another method. Practical implications: Solutions presented in the work, based on using the adequate material models may feature an interesting alternative in designing of the new materials with the required properties. The practical aspect has to be noted, resulting form the developed models, which may successfully replace the above mentioned technological investigations, consisting in one time selection of the chemical composition and heat treatment parameters and experimental verification of the newly developed materials to check of its properties meet the requirements. Originality/value: The presented approach to new materials design assumes the maximum possible limitation of carrying out the indispensable experiments, to take advantage of the existing experimental knowledge resources in the form of databases and most effective computer science tools, including neural networks and evolutionary algorithms.

17

Numerical simulation of the alloying elements effect on steels’ properties

Sitek W., Trzaska J.

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 45, nr 1

71--78

EN

Purpose: The goal of the research carried out was evaluation of alloying elements effect on high-speed steels hardness and fracture toughness and austenite transformations during continuous cooling of structural steels. Design/methodology/approach: Multi-layer feedforward neural networks with learning rule based on the error backpropagation algorithm were employed for modelling the steels properties. Then the neural networks worked out were employed for the computer simulation of the effect of particular alloying elements on the steels’ properties. Findings: Obtained results show that neural network are useful in evaluation of synergic effect of alloying elements on selected materials properties when classical investigations’ results do not provide evaluation of the effect of two or more alloying elements. Practical implications: Numerical simulation presented in the work, based on using the adequate material models may feature an alternative for classical investigations on effect of alloying elements on steels’ properties. Originality/value: The use of the neural networks as an tool for evaluation of the chemical composition effect on steels’ properties.

18

Wykorzystanie metody anihilacji pozytonów do badań struktury i własności defektów strukturalnych w przypowierzchniowych warstwach stali 12H17T i 12H18N10T

Durjagina Z., Pietrzak R., Szczerbowski N., Szatanik R.

Inżynieria Powierzchni

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2009

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Nr 4

46-50

PL

W pracy wskazano na możliwość zastosowania metody anihilacji pozytonów do badań procesu tworzenia i właściwości defektów strukturalnych w przypowierzchniowych warstwach skorodowanej austenistycznej i ferrytyczno-martenzytycznej stali. Badano właściwości morfologiczne i topologię rozkładu defektów na różnych głębokościach zdefektowanych warstw oraz dokonano oceny parametrów rozmiarowych zidentyfikowanych defektów.

EN

A possibility of using the positron annihilation method to investigate creation and properties of structural defects in superficial layers of corroded austenitic and ferrite-martensitic steels is pointed out in the paper. The morphological properties and the topology of distribution of defects were studied on different depths of defected layers, as well as an assessment was made of dimension parameters of the identified defects.

19

Automatic classification of the 13CrMo4-5 steel worked in creep conditions

Dobrzański J., Sroka M.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 29, nr 2

147-150

EN

Purpose: In material engineering the images obtained by various methods are the source of different information about materials. The artificial intelligence tools can be employed for automatic method for analysis of scanning electron microscope metallographic images of elements after long time operating in creep services. Design/methodology/approach: The methodology allows to work out a system of automatic classification of internal damages in 13CrMo4-5 steel working in creep conditions on the base of computational images analysis by the use of artificial neural networks. Input vectors of artificial neural networks were optimized by the use of genetic algorithms. Findings: The methodology of digital image analysis allowing identification of geometrical coefficients characterizing damages in the materials after long-time operating in creep conditions and methodology of classification of these damages by the use of artificial neural network were evaluated. Practical implications: The presented method can be use as a practical application for classification of creep-damages of elements power industry installations components operating in creep conditions. Originality/value: Applying of images analysis and neural networks to identification and classification of internal damages of 13CrMo4-5 steel working in creep conditions could shorten the time of classification and eliminate of many subjective errors made by humans.

20

Struktura geometryczna powierzchni stali po frezowaniu igłowym stali

Feldshtein E., Laber S., Barshaj I., Hancharou S.

Tribologia

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2007

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nr 5

39-52

PL

W pracy przedstawiono wyniki badań struktury geometrycznej powierzchni płaskich po procesie frezowania igłowego elementów z nisko-stopowych stali różnych gatunków, stosowanych w produkcji kół zębatych. Ustalono wpływ prędkości, posuwu i docisku przy frezowaniu igłowym na szereg parametrów chropowatości powierzchni. W zależności od warunków obróbki parametry chropowatości zmieniają się w szerokim zakresie, np. Ra - od 2,6 do 6 žm. Stereometria powierzchni po frezowaniu igłowym frezem tarczowym jest bardzo niejednorodna. Na powierzchni obserwuje się rozmieszczone przypadkowo występy, bruzdy, rysy, nalepy. Taki kształt powierzchni zasadniczo różni się od tradycyjnych metod obróbki powierzchni płaskich frezowaniem bądź szlifowaniem.

EN

In the paper the results of researches of surface geometrical structure after brush milling of steel parts are described. Low-doped steels using for gears production such as 12XH3A, 25XGM, 25XGT, 20XH3A and 20XHP (according Russian standard GOST 4345-71) were tested. Chemical compositions and mechanical properties of tested steels are shown in Tab. 1 and 2. Geometrical structure of flat surfaces after brush milling by mill from steel wires with 0,3 mm diameter and 20 mm length was researched. The package density was equal 75-85% (Fig. 1). Speed Vc and feed f of milling and mill tightness W were changed. The mathematical method of research was used which allowed to place research points thereby their projections to X1-X2, X2-X3,..., Xi-Xj axis were equal. The plane matrix is shown in Tab. 3, considering Ximin = 0 and XimaX = 1, and really coordinates - in Tab. 4. Rough profile records of steel 12XH3A surfaces milling with different parameters are shown in Fig. 2, and 1-7 numbers are agreed coordinates from Tab. 4. Minimal vertical parameters of roughness were obtained when Vc = 127 m/min, f = 85 mm/min, W = 0,28 mm and maximal parameters - when Vc = 42 m/min, f = 690 mm/min, W = 0,39 mm (Fig. 3). Minimum of mean width of the profile elements RSm was obtained when Vc = 295 m/min, f = 400 mm/min, W = 0,06 mm and maximum - when Vc = 42 m/min, f = 690 mm/min, W = 0,39 mm. Minimum material ratio of the profile Rmr(50) was obtained when Vc = 211 m/min, f = 270 mm/min, W = 0,17 mm and maximum - when Vc = 84 m/min, f = 530 mm/min, W= 0,11 mm. Line multivariate regression equations to calculate Ra, Rq, Rz, Rp, Rv and RSm roughness parameters for steel 12XH3A were obtained, and equalizing coefficients for steel 20XH3A - 1,50; steel 20XHP - 1,07; steel 25XGM - 1,25 and steel 25XGT - 1,27 can be used. Graphical interpretations on Fig. 4,5 are shown. Surfaces stereometry after brush milling are shown on Fig. 6 (1-7 numbers are agreed coordinates from Tab. 4). Grind surface is shown as number 8 for comparison. It can be easy noticed then surfaces stereometry after brush milling is very complicated and have hairlines, pickups, profile peaks and valley and so on. Such surface can facilitate coating bonding on base steel and also can influence positively on lubrication when wearing.