Retained Austenite Decomposition and Carbide Precipitation during Isothermal Tempering of a Medium-Carbon Low-Alloy Bainitic Steel

Seyyed Talebi; Mohammad Jahazi; Haikouhi Melkonyan

doi:10.3390/ma11081441

Retained Austenite Decomposition and Carbide Precipitation during Isothermal Tempering of a Medium-Carbon Low-Alloy Bainitic Steel

Materials ◽

10.3390/ma11081441 ◽

2018 ◽

Vol 11 (8) ◽

pp. 1441 ◽

Cited By ~ 3

Author(s):

Seyyed Talebi ◽

Mohammad Jahazi ◽

Haikouhi Melkonyan

Keyword(s):

Electron Microscopy ◽

Retained Austenite ◽

Carbide Precipitation ◽

Austenite Decomposition ◽

Bainitic Steel ◽

Tempering Temperature ◽

Medium Carbon ◽

Transmission Electron ◽

Decomposition Behavior ◽

Isothermal Tempering

The effect of isothermal tempering on retained austenite decomposition and carbide precipitation were investigated in a medium-carbon low-alloy bainitic steel. High-resolution dilatometry was used to perform isothermal tempering at 350 °C, 550 °C and 600 °C for different holding times up to 16 h. The decomposition of retained austenite, morphology and composition of carbides were investigated by analyzing the dilatometric curves and were confirmed through scanning and transmission electron microscopy observations. The decomposition behavior of retained austenite varied significantly as a function of the tempering temperature with a full decomposition observed at 600 °C. It was also found that by increasing the tempering temperature from 550 °C to 600 °C, carbides precipitate approximately twice as fast, and evolve from M3C type to Cr7C3 and Cr23C6 after 16 h of tempering at 600 °C.

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Strengthening Mechanism and Thermal Stability of Spray Formed H13 Steel

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.295.49 ◽

2019 ◽

Vol 295 ◽

pp. 49-56

Author(s):

Zhan Zhan Zhang ◽

Wan Zhen Wang ◽

Yun Bo Chen ◽

Miao Hui Wang ◽

Chang De Zhao ◽

...

Keyword(s):

Electron Microscopy ◽

Thermal Stability ◽

Transmission Electron Microscopy ◽

Strengthening Mechanism ◽

H13 Steel ◽

Tempering Temperature ◽

Transmission Electron ◽

Tempering Treatment ◽

Hardness Values ◽

Thermal Stability Of

The aim of this work is to study the strengthening mechanism and thermal stability of spray formed H13 steel. The microstructure and hardness of spray formed H13 steels are investigated by electron microscopy, transmission electron microscopy and hardness measurementscanning. The calculated results demonstrate that tensile strength, impact energy and hardness values of sprayed-formed H13 steel are higher than that of as-cast H13 steel when the tempering temperature is 600 °C after quenched at 1050 °C. Compared with as-cast H13 steels, tempered spray-formed H13 steels possess supernal high-temperature temper resistant stability. The chemical composition of the carbides in spray-formed steels is V and Cr rich spherical carbides are hardly influenced by the tempering treatment.

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Paper 24: Dry Wear of Steel as Revealed by Electron Microscopy and X-Ray Diffraction

Proceedings of the Institution of Mechanical Engineers Conference Proceedings ◽

10.1243/pime_conf_1967_182_423_02 ◽

1967 ◽

Vol 182 (14) ◽

pp. 201-213

Author(s):

T. F. J. Quinn

Keyword(s):

Electron Microscopy ◽

Medium Carbon Steel ◽

X Ray Diffraction ◽

Medium Carbon ◽

X Ray ◽

Ambient Temperatures ◽

Transmission Electron ◽

Steel Aisi ◽

Diffraction Patterns ◽

Fatigue Failures

Low-alloy, medium-carbon steel (AISI 4340) pins have been worn against discs of the same material at various loads under unlubricated (‘dry’) sliding conditions. Shadowed carbon replicas have been obtained from the surfaces of selected pins and discs. Transmission electron microscopy of these replicas revealed several interesting features, the most interesting being the presence of reproducible crack systems occurring in those parts of the surface at which the wear is taking place. These cracks are very similar to those obtained in fatigue failures. X-ray diffraction patterns were also obtained from these specimens, and from the corresponding wear debris. These indicated that oxidation had occurred at temperatures considerably in excess of the measured ambient temperatures. The various topographic and crystallographic features revealed by the electron microscopy and X-ray diffraction techniques are discussed in relation to a possible mechanism of ‘dry’ wear

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Variation of the Reversed Austenite Amount with the Tempering Temperature in a Fe-13%Cr-4%Ni-Mo Martensitic Stainless Steel

Materials Science Forum ◽

10.4028/www.scientific.net/msf.650.193 ◽

2010 ◽

Vol 650 ◽

pp. 193-198 ◽

Cited By ~ 4

Author(s):

Yuan Yuan Song ◽

Xiu Yan Li ◽

Fu Xing Yin ◽

De Hai Ping ◽

Li Jian Rong ◽

...

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Stainless Steel ◽

Martensitic Stainless Steel ◽

Low Carbon ◽

Reversed Austenite ◽

X Ray Diffraction ◽

Tempering Temperature ◽

X Ray ◽

Transmission Electron

Tempering temperature dependence of the amount of the reversed austenite in the range of 570 oC to 680 oC was investigated by means of X-ray diffraction (XRD) measurements and transmission electron microscopy (TEM) in a low carbon Fe-13%Cr-4%Ni-Mo (wt.%) martensitic stainless steel. It was found that the reversed austenite began to form at the tempered temperature slightly above the As temperature. As the tempered temperature increased, the amount of the reversed austenite changed little in the temperature range of 580-595 oC. Then, the amount of the reversed austenite increased sharply with the increased tempered temperature. When the tempered temperature increased to about 620 oC, the amount of the reversed austenite exhibited a peak. Afterward, it decreased quickly at the elevated tempered temperature. The microstructural evolvement of the reversed austenite at different tempering temperature was also observed by TEM.

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Carbide Precipitation in 2.25 Cr-1 Mo Bainitic Steel: Effect of Heating and Isothermal Tempering Conditions

Metallurgical and Materials Transactions A ◽

10.1007/s11661-017-4045-6 ◽

2017 ◽

Vol 48 (5) ◽

pp. 2164-2178 ◽

Cited By ~ 14

Author(s):

Sylvain Dépinoy ◽

Caroline Toffolon-Masclet ◽

Stéphane Urvoy ◽

Justine Roubaud ◽

Bernard Marini ◽

...

Keyword(s):

Carbide Precipitation ◽

Bainitic Steel ◽

Isothermal Tempering

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Microstructural Features of Strain-Induced Martensitic Transformation in Medium-Mn Steels with Metastable Retained Austenite/ Cechy Mikrostrukturalne Indukowanej Odkształceniem Przemiany Martenzytycznej W Stalach Sredniomanganowych Z Metastabilnym Austenitem Szczątkowym

Archives of Metallurgy and Materials ◽

10.2478/amm-2014-0283 ◽

2014 ◽

Vol 59 (4) ◽

pp. 1673-1678 ◽

Cited By ~ 2

Author(s):

A. Grajcar ◽

A. Kilarski ◽

K. Radwanski ◽

R. Swadzba

Keyword(s):

Electron Microscopy ◽

Retained Austenite ◽

Volume Fraction ◽

Electron Backscatter Diffraction ◽

Bainitic Ferrite ◽

Tensile Tests ◽

Bainitic Steels ◽

Transmission Electron ◽

Strain Induced Martensite ◽

Backscatter Diffraction

Abstract The work addresses relationships between the microstructure evolution and mechanical properties of two thermomechanically processed bainitic steels containing 3 and 5% Mn. The steels contain blocky-type and interlath metastable retained austenite embeded between laths of bainitic ferrite. To monitor the transformation behaviour of retained austenite into strain-induced martensite tensile tests were interrupted at 5%, 10%, and rupture strain. The identification of retained austenite and strain-induced martensite was carried out using light microscopy (LM), scanning electron microscopy (SEM) equipped with EBSD (Electron Backscatter Diffraction) and transmission electron microscopy (TEM). The amount of retained austenite was determined by XRD. It was found that the increase of Mn addition from 3 to 5% detrimentally decreases a volume fraction of retained austenite, its carbon content, and ductility.

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Effect of Heat Treatment Process on Microstructure and Properties in Low Carbon Si-Mn Q&P Steel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.233-235.1009 ◽

2011 ◽

Vol 233-235 ◽

pp. 1009-1013

Author(s):

Cai Zhao ◽

Di Tang

Keyword(s):

Electron Microscopy ◽

Mechanical Properties ◽

Heat Treatment ◽

Retained Austenite ◽

Treatment Process ◽

Lath Martensite ◽

Heat Treatment Process ◽

Low Carbon ◽

Transmission Electron ◽

Partitioning Time

The mechanical properties of Low Carbon Si-Mn Q&P steel are strongly affected by the conditions of heat treatment. Microstructures and mechanical properties of Low Carbon Si-Mn Q&P steel at different partitioning temperature and holding time was investigated. The microstructure was analysed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It is shown that the microstructure of Q&P steel is carbon-depleted lath martensite and carbon enriched retained austenite. The retained austenite appear film-type between the laths. Higher partitioning temperature and longer partitioning time can obtain more retained austenite. It is shown that with increasing partitioning time ultimate tensile strength decreases, while elongation increases obviously. Carbon-enriched metastable retained austenite is considered beneficial because the TRIP phenomenon during deformation can contribute to formability and energy absorption.

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Dynamic continuous cooling transformation, microstructure and mechanical properties of medium-carbon carbide-free bainitic steel

High Temperature Materials and Processes ◽

10.1515/htmp-2020-0051 ◽

2020 ◽

Vol 39 (1) ◽

pp. 304-316

Author(s):

Xi Chen ◽

Fuming Wang ◽

Changrong Li ◽

Jing Zhang

Keyword(s):

Cooling Rate ◽

Retained Austenite ◽

Charpy Impact ◽

Granular Bainite ◽

Morphology Evolution ◽

Bainitic Steel ◽

Cooling Process ◽

Medium Carbon ◽

Continuous Cooling ◽

Lath Bainite

AbstractThe effects of the cooling rate after hot deformation on phase transformation, the microstructure of the designed nonquenched and tempered medium-carbon carbide-free bainitic steel have been investigated during the dynamic continuous cooling process. The results show that with the increase of the cooling rate, the morphology of the carbide-free bainite of the experimental steel evolves from granular bainite to lath bainite. Meanwhile, the hardness increases, and the amount of the retained austenite decreases with the increase of the cooling rate. Besides, the morphology evolution of the retained austenite from block to film is revealed by EBSD. Moreover, 0.5°C/s is considered to be the favorable cooling rate to obtain the best strength–toughness matching. Furthermore, the semi-industrial experimental results proved that the tensile strength, yield strength and Charpy impact energy were 1,298 MPa, 847 MPa and 38 J, respectively.

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Influence of Quenching-Tempering on the Carbide Precipitation of 2.25Cr-1Mo-0.25V Steel Used in Reactor Pressure Vessels

Volume 3: Design and Analysis ◽

10.1115/pvp2019-93054 ◽

2019 ◽

Author(s):

Yafei Wang ◽

Songyan Hu ◽

Guangxu Cheng ◽

Zaoxiao Zhang ◽

Jianxiao Zhang

Keyword(s):

Electron Microscopy ◽

Heat Treatment ◽

Pressure Vessels ◽

Carbide Precipitation ◽

Amorphous Films ◽

Replica Technique ◽

Selected Area Electron Diffraction ◽

Transmission Electron ◽

Before And After ◽

Reactor Pressure

Abstract The carbide precipitation of 2.25Cr-1Mo-0.25V steel is studied during the head-fabrication heat treatment process using gold replica technique, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and selected area electron diffraction (SAED). Shapes, structures and sizes of carbides before and after heat treatment are analyzed. The dissolution of strip-shaped carbides and the precipitation of granular carbides are confirmed. Amorphous films at the boundaries of carbides are observed by high-resolution transmission electron microscope (HRTEM), which is formed due to the electron irradiation under TEM.

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Effect of Isothermal Transformation Times below Ms and Tempering on Strength and Toughness of Low-Temperature Bainite in 0.53 C Bainitic Steel

Materials ◽

10.3390/ma13102418 ◽

2020 ◽

Vol 13 (10) ◽

pp. 2418

Author(s):

Enzuo Liu ◽

Qiangguo Li ◽

Sufyan Naseem ◽

Xuefei Huang ◽

Weigang Huang

Keyword(s):

Low Temperature ◽

Impact Toughness ◽

Retained Austenite ◽

Volume Fraction ◽

Isothermal Transformation ◽

Electron Back Scatter Diffraction ◽

Bainitic Steel ◽

Transmission Electron ◽

The Impact ◽

Tempering Process

This study aims to investigate the microstructures, strength, and impact toughness of low-temperature bainite obtained by isothermal transformation at temperature below Ms (Martensite Starting temperature) for different times and tempering process in 0.53 C wt% bainitic steel. By using the optical microscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), electron back scatter diffraction (EBSD), and mechanical property test, it was found that the microstructures after heat treatment consist of small amounts of martensite, fine bainite, and film retained austenite. After tempered at 250 °C for 2 h, the volume fraction of retained austenite (10.9%) in the sample treated by isothermal transformation at 220 °C for three hours is almost the same as that of the sample without tempering. In addition, the retained austenite fraction decreases with the increase of holding times and is reduced to 6.8% after holding for 15 h. The ultimate tensile strength (1827 MPa), yield strength (1496 MPa), total elongations (16.1%), and impact toughness (up to 58 J/cm2) were obtained by isothermal transformation at 220 °C for three hours and tempered at 250 °C. Whereas, the impact toughness of sample without tempering is 28 J/cm2. After holding for 15 h, the impact toughness raises to 56 J/cm2, while the ductility and strength decreases. These results indicate that the tempering process is helpful to improve the impact toughness of low-temperature bainite.

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