Temat: austenite - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Precise Orientation Control of Single Crystalline NiMnGa-Based Alloys by in-situ EBSD Analysis
Autorzy:: Szewczyk, Arkadiusz
Faryna, Marek
Wójcik, Anna
Maziarz, Wojciech
Chulist, Robert
Tematy:: orientation
monocrystal
EBSD
austenite
martensite; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59110703.pdf Link otwiera się w nowym oknie
Opis:: The article presents a precise method for the orientation process of NiMnGa-based single crystals. For this method, a scanning electron microscope equipped with an EBSD camera and a heating stage allowing temperatures exceeding 873 K was used. The orientation process was carried out in both the high-temperature austenite phase and in the room-temperature martensite phase. The facilities allowed for determining the orientation of a single grain of austenite at elevated temperatures as well as the orientation of particular martensitic variants at room temperature. A practically perfect cubic orientation was obtained in the austenitic case with a deviation of about 1° while the samples oriented in the martensitic phase deviated from the desired orientation by 4.5-5.2°. Additionally, the training process of single crystals was carried out in order to show the influence of the orientation process on twinning stress.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Austenit szczątkowy w stalach węglowych i stopowych
Retained austenite in carbon steels and alloy one
Autorzy:: Jeleńkowski, J.
Tematy:: retained austenite
alloy steel
atermical kinetict; Pokaż więcej
Wydawca:: Wydawnictwo AWART
Powiązania:: https://bibliotekanauki.pl/articles/404605.pdf Link otwiera się w nowym oknie
Opis:: W artykule omówiono niektóre z przyczyn obecności austenitu szczątkowego w stalach stopowych, fazy będącej ubocznym produktem przemiany martenzytycznej. Stale stopowe zawierają zawsze pewne ilości austenitu szczątkowego, więcej te spośród nich, w których austenit obok kinetyki atermicznej może się przemieniać izotermicznie w martenzyt. Niektóre z nich charakteryzują się unikatowym wpływem szybkości chłodzenia na stabilność austenitu. Nieprzemieniony, stabilizowany bardziej stopowy austenit rozmieszcza się na granicach ziaren.
Some problems of a presence of the retained austenite in the alloy steels, are disscused in the paper. The phase of aicidental product of the martensite transformation is also included into consideration. The alloy steel susually contains a carbon a certains amount of the retained austenite and that is more some of this can be isothermaly changed in martensite, independently near the atermical kineticts of austenite. Some a transformation can be characterized by original influence of the cooling speed on the austenite stability. Unchanged but stabilized alloy austenit eis located an the grain bondiers.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Using the Principles of Image Analysis in the Assessment of the Proportion of Retained Austenite in the Case Hardened Layers
Autorzy:: Váňová, P.
Sojka, J.
Kulová, T.
Jokešová, K.
Purtátor, P.
Spinu, A.
Tematy:: retained austenite
carburized layers
image analysis; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355652.pdf Link otwiera się w nowym oknie
Opis:: Structures of carburized layers after the surface saturation process in gaseous, liquid or solid medium and after subsequent heat treatment (hardening and low-temperature tempering) consist mainly of high carbon plate martensite with a certain portion of retained austenite. The presence of retained austenite (RA) in carburized layers is mostly considered as undesirable because it decreases hardness of the hardened layer and furthermore, a spontaneous conversion to a ferritic-carbide mixture of a bainitic type, accompanied by a change of properties, dimensional instability and the local increase in internal stress with the possible formation of cracks, can occur. The proportion of retained austenite is, therefore, a significant characteristics of the quality of hardened layers. This work deals with the evaluation of the volume fraction of retained austenite in carburized layers using image analysis on metallographic images.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Austenite Grain Size Estimtion from Chord Lengths of Logarithmic-Normal Distribution
Autorzy:: Adrian, H.
Wiencek, K.
Tematy:: austenite grain size
linear section methods
modelling; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352085.pdf Link otwiera się w nowym oknie
Opis:: Linear section of grains in polyhedral material microstructure is a system of chords. The mean length of chords is the linear grain size of the microstructure. For the prior austenite grains of low alloy structural steels, the chord length is a random variable of gamma- or logarithmic-normal distribution. The statistical grain size estimation belongs to the quantitative metallographic problems. The so-called point estimation is a well known procedure. The interval estimation (grain size confidence interval) for the gamma distribution was given elsewhere, but for the logarithmic-normal distribution is the subject of the present contribution. The statistical analysis is analogous to the one for the gamma distribution.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Effect of Delta Ferrite on the Mechanical Properties of Dissimilar Ferritic-Austenitic Stainless Steel Welds
Autorzy:: Ghasemi, R.
Beidokhti, B.
Fazel-Najafabadi, M.
Tematy:: stainless steel
welding
delta ferrite
electron microscopy
austenite; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353040.pdf Link otwiera się w nowym oknie
Opis:: The dissimilar welds of AISI 304 to AISI 430 stainless steel was investigated by using gas tungsten arc welding. Three filler metals including ER309L, ER316L and ER2594 were applied. The weakest region of the welds was the heat affected zone of 430 stainless steel due to the formation of martensite. Also, the wide grain growth zone was observed in this side. The ferrite number for type 309L, 316L and 2594 weld metals was about 15, 32 and 57, respectively. The hardness and tensile strength values of the weld metals were higher than that of the heat affected zones and the base metals. The ferrite presented higher hardness values than the austenite in type 316L and 309L joints; while the hardness of austenite and ferrite was comparable in type 2594 weld metal.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Influence of Heat Treatment and Nickel Content on the Properties of the GX4CrNi13-4 Steel
Autorzy:: Kaňa, V.
Krutiš, V.
Bořil, P.
Záděra, A.
Rimko, M.
Tematy:: martensitic steel
retained austenite
mechanical properties
heat treatment; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2049568.pdf Link otwiera się w nowym oknie
Opis:: For the EN GX4CrNi13-4 martensitic stainless steel, research was conducted to investigate the impact of the quenching intensity and the content of nickel on the mechanical properties and amount of retained austenite. It was found that the amount of retained austenite significantly increases with growing nickel concentration. On the other hand, the cooling rate at quenching makes a difference only if the cooling is intensive, then amount of retained austenite decrease. A higher nickel content improves the mechanical properties. With more intensive cooling, the tensile strength decreases while the yield strength increases. The ductility is not significantly affected by the cooling intensity.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Effect of Element Addition, Microstructure Characteristics, Mechanical Properties, Machining and Welding Processes of the Hadfield Austenitic Manganese Steel
Autorzy:: Zellagui, Rihab
Hemmouche, Larbi
Ait-Sadi, Hassiba
Chelli, Amel
Tematy:: Hadfield steel
austenite
carbides
element addition effect
machinability
welding; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2125536.pdf Link otwiera się w nowym oknie
Opis:: High manganese steel, also called Hadfield steel, is an alloy essentially made up of iron, carbon, and manganese. This type of steel occupies an important place in the industry. It possesses high impact toughness and high resistance against abrasive wear and hardens considerably during work hardening. The problem with this kind of steel is the generation of carbides at the grain boundaries after the casting. However, heat treatment at the high-temperature range between 950°C and 1150°C followed by rapid quenching in water is proposed as a solution to remove carbides and obtain a fully austenitic structure. Under the work hardening effects, the hardness of Hadfield steel increases greatly due to the transformation of the austenite γ to martensite ε or α and mechanical twinning, which acts as an obstacle for sliding dislocations. Hot machining is the only solution to machine Hadfield steel adequately without damage of tools or changing the mechanical characteristics of the steel. The choice of welding parameters is important to prevent the formation of carbides and obtain welded steel with great characteristics. This paper aims to give an overview about Hadfield steel, element addition effect, microstructure, heat treatments, work hardening, machinability and welding processes.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Mechanical Properties of a Bainitic Steel Producible by Hot Rolling
Autorzy:: Rana, R.
Chen, S.
Haldar, A.
Das, S.
Tematy:: carbide-free bainite
retained austenite
hot rolling
mechanical properties; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/352494.pdf Link otwiera się w nowym oknie
Opis:: A carbide-free bainitic microstructure is suitable for achieving a combination of ultra high strength and high ductility. In this work, a steel containing nominally 0.34C-2Mn-1.5Si-1Cr (wt.%) was produced via industrial hot rolling and laboratory heat treatments. The austenitization (900°C, 30 min.) and austempering (300-400°C, 3 h) treatments were done in salt bath furnaces. The austempering treatments were designed to approximately simulate the coiling step, following hot rolling and run-out-table cooling, when the bainitic transformation would take place and certain amount of austenite would be stabilized due to suppression of carbide precipitation. The microstructures and various mechanical properties (tensile properties, bendability, flangeability, and room and subzero temperature impact toughness) relevant for applications were characterized. It was found that the mechanical properties were highly dependent on the stability of the retained austenite, presence of martensite in the microstructure and the size of the microstructural constituents. The highest amount of retained austenite (~ 27 wt.%) was obtained in the sample austempered at 375°C but due to lower austenite stability and coarser overall microstructure, the sample exhibited lower tensile ductility, bendability, flangeability and impact toughness. The sample austempered at 400°C also showed poor properties due to the presence of initial martensite and coarse microstructure. The best combination of mechanical properties was achieved for the samples austempered at 325-350°C with a lower amount of retained austenite but with the highest mechanical stability.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Austenitic Stability and Strain-Induced Martensitic Transformation Behavior of Nanocrystalline FeNiCrMoC HSLA Steels
Autorzy:: Park, Jungbin
Jeon, Junhyub
Seo, Namhyuk
Kim, Gwanghun
Son, Seung Bae
Jung, Jae-Gil
Lee, Seok-Jae
Tematy:: nanocrystalline
austenite stability
strain induced martensite
transformation induced plasticity; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2203710.pdf Link otwiera się w nowym oknie
Opis:: The austenitic stability and strain-induced martensitic transformation behavior of a nanocrystalline FeNiCrMoC alloy were investigated. The alloy was fabricated by high-energy ball milling and spark plasma sintering. The phase fraction and grain size were measured using X-ray diffraction. The grain sizes of the milled powder and the sintered alloy were confirmed to be on the order of several nanometers. The variation in the austenite fraction according to compressive deformation was measured, and the austenite stability and strain-induced martensitic transformation behavior were calculated. The hardness was measured to evaluate the mechanical properties according to compression deformation, which confirmed that the hardness increased to 64.03 HRC when compressed up to 30%.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Microstructure and Impact Toughness of Offshore Steel
Autorzy:: Cheng, T.-C.
Yu, C.
Yang, T.-C.
Huang, C.-Y.
Lin, H.-C.
Shiue, R.-K.
Tematy:: low-temperature impact toughness
prior austenite grain size
hardenability
bainite; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351264.pdf Link otwiera się w nowym oknie
Opis:: This study focused on the effects of microstructures on the low-temperature impact toughness of directly water-quenched offshore steel. Martensite dominated the microstructure directly below the quenched surface. In contrast, mainly lower bainite, martensite, and low amount of ferrite were observed in the central region of the quenched specimen. The ductile to brittle transition temperature of tempered martensite was significantly lower than that of a bainite-dominated microstructure. It is found that low-angle boundaries within the bainite packets greatly impair the low-temperature impact toughness of the steel. The absence of high-angle boundaries in the lower bainite packets significantly deteriorates the low-temperature impact energy of offshore steel.
Dostawca treści:: Biblioteka Nauki

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