Metallurgical Characterization and Kinetics of Borided 34CrNiMo6 Steel

AbstractBoriding of 34CrNiMo6 steel was performed in a solid medium consisting of Ekabor-II powders at 1123, 1173 and 1223 K for 2, 4 and 6 h. Morphological and kinetic examinations of the boride layers were carried out by optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The thicknesses of the boride layers ranged from 22±2.3 to 145±4.1 depending on boriding temperature and time. The hardness of boride layer was about 1857 HV0.1 after boriding for 6 h at 1223 K, while the hardness of the substrate was only around 238 HV0.1. Growth rate constants were found to be between 1.2×10−13 – 9.8×10−13 m2/s depending on temperature. The activation energy for boron diffusion was estimated as 239.4±8.6 kJ mol−1. This value was comparable to the activation energies reported for medium carbon steels in the literature.

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Effect of the Boron Powder on Surface AISI W2 Steel: Experiments and Modelling

Advances in Materials Science and Engineering ◽

10.1155/2021/5548004 ◽

2021 ◽

Vol 2021 ◽

pp. 1-9

Author(s):

Marco Antonio Doñu Ruiz ◽

David Sánchez Huitron ◽

Ernesto David Garcia Bustos ◽

Víctor Jorge Cortés Suárez ◽

Noé López Perrusquia

Keyword(s):

Energy Dispersive Spectrometry ◽

Single Layer ◽

Boride Layer ◽

Boron Diffusion ◽

Mass Balance Equation ◽

X Ray Diffraction ◽

Experimental Conditions ◽

Boron Powder ◽

X Ray ◽

Kinetics Of

The effect of boron powder on surface AISI W2 steel and growth kinetic of the boride layer is studied. Boron powder mixture was used in the powder pack boriding; this process was carried out in the temperature range from 1173 to 1273 K with exposure times ranging from 2 to 8 h. The presence of boride was confirmed by optical microscopy, X-ray diffraction, and the distribution of alloy elements in boride layers with energy-dispersive spectrometry using scanning electron microscopy. A mathematical model of the growth kinetics of the single layer was proposed and boron diffusion coefficient was determined by mass balance equation. The morphology of Fe2B layer was smooth and boron activation energy in W2 steel was estimated as 187.696 kJ·mol−1. The kinetic model was validated with two experimental conditions, a contour diagram describing the evolution of Fe2B layer as a function of time and temperature parameters for industrial application.

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Investigation of Growth Kinetics of Fe2B Layers on AISI 1518 Steel by the Integral Method

High Temperature Materials and Processes ◽

10.1515/htmp-2017-0166 ◽

2019 ◽

Vol 38 (2019) ◽

pp. 219-228

Author(s):

M. Elias-Espinosa ◽

M. Keddam ◽

M. Ortiz-Domínguez ◽

A. Arenas-Flores ◽

J. Zuno-Silva ◽

...

Keyword(s):

Alternative Model ◽

Present Model ◽

Boride Layer ◽

Boron Diffusion ◽

Mass Balance Equation ◽

X Ray Diffraction ◽

X Ray ◽

Temperature Range ◽

Eds Analysis ◽

Kinetics Of

AbstractThe AISI 1518 steel was pack-borided in the temperature range 1123–1273 K for a treatment ranging from 2 to 8 h. A compact single boride layer (Fe2B) was formed at the surface of the AISI 1518 steel using the mixture of powders composed of 20 % B4C, 10 % KBF4 and 70 % SiC. The following experimental techniques such as scanning electron microscopy coupled with EDS analysis and X-ray diffraction analysis were employed to characterize the pack-borided AISI 1518 steel. An alternative model, based on the integral mass balance equation, was used to estimate the boron diffusion coefficients in the Fe2B layers in the temperature range 1123–1273 K. Finally, the value of activation energy for boron diffusion in the AISI 1518 steel was estimated and compared with the literature data. Furthermore, the present model was validated by comparing the experimental value of Fe2B layer thickness, obtained at 1253 K for 2 h of treatment, with the predicted value.

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The Influence of Vanadium Additions on Isothermally Formed Bainite Microstructures in Medium Carbon Steels Containing Retained Austenite

Metals ◽

10.3390/met10030392 ◽

2020 ◽

Vol 10 (3) ◽

pp. 392 ◽

Cited By ~ 3

Author(s):

Irina Pushkareva ◽

Babak Shalchi-Amirkhiz ◽

Sébastien Yves Pierre Allain ◽

Guillaume Geandier ◽

Fateh Fazeli ◽

...

Keyword(s):

Retained Austenite ◽

Bainitic Ferrite ◽

High Energy ◽

Carbon Steels ◽

Ex Situ ◽

Transformation Rate ◽

Medium Carbon ◽

X Ray ◽

Medium Carbon Steels ◽

Carbon Mass Balance

The influence of V additions on isothermally formed bainite in medium carbon steels containing retained austenite has been investigated using in-situ high energy X-ray diffraction (HEXRD) and ex-situ electron energy loss spectroscopy (EELS) and energy dispersive X-ray analysis (EDX) techniques in the transmission electron microscope (TEM). No significant impact of V in solid solution on the bainite transformation rate, final phase fractions or on the width of bainite laths was seen for transformations in the range 375–430 °C. No strong influence on the dislocation density could be detected, although quantitative analysis was impeded by ferrite tetragonality. A reduction in the carbon content of retained austenite Cγ that is not believed to be due to competition with VC or cementite precipitation was observed. No influence of V on the carbon supersaturation in bainitic ferrite Cb could be directly measured, although carbon mass balance calculations suggest Cb slightly increases. A beneficial refinement of blocky MA and a corresponding size effect induced enhancement in austenite stability were found at the lowest transformation temperature. Overall, V additions result in a slight increase in strength levels.

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Electron-Metallographic Identification of Retained Austenite in Steels

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113779 ◽

1975 ◽

Vol 33 ◽

pp. 30-31 ◽

Cited By ~ 2

Author(s):

B. V. Narasimha Rao ◽

J. Y. Koo ◽

G. Thomas

Keyword(s):

Retained Austenite ◽

Dark Field ◽

Carbon Steels ◽

Electron Microscopic ◽

Medium Carbon ◽

X Ray ◽

Dark Field Imaging ◽

Medium Carbon Steels ◽

Field Imaging ◽

Microscopic Techniques

Recently it has been discovered by electron microscopy that even in medium carbon steels (Mf≳200°C) small quantities of interlath retained austenite (γ) is present in as-quenched structures. It is speculated that this small quantity of retained γ can have a profound influence on the mechanical properties of steel. This austenite is severely deformed and in most cases the amount is so small that detection by x-ray analysis becomes impossible. However, sophisticated electron microscopic techniques involving careful selected area diffraction, bright field and dark field imaging can unequivocally establish the presence of such small quantities of austentite. Extremely useful morphological and microstructural information on the austenite can also be obtained from the electron metallography.

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Study and Properties of a Steel Microalloyed Hardened Superficially

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.365.122 ◽

2015 ◽

Vol 365 ◽

pp. 122-127 ◽

Cited By ~ 2

Author(s):

N. López-Perrusquia ◽

M.A. Doñu Ruiz ◽

C. R. Torres San-Miguel ◽

M. Flores-Báez ◽

I. Flores-Báez

Keyword(s):

Growth Process ◽

Energy Dispersive Spectrometry ◽

Boride Layer ◽

X Ray Diffraction ◽

X Ray ◽

Diffusion Controlled ◽

Boriding Process ◽

Kinetics Of ◽

Over Time ◽

Scanning Electron

In this study, we present a boronizing treatment on a steel microalloy that was performed according to dehydrated paste-pack boriding. The temperatures conducted were at 1173, 1223 and 1273 K; at various exposure times of 1, 3, 6 and 9 h. As a result of the boriding process, diffusion-controlled growth of the FeB/Fe2B layers was obtained at the surface of the micro-alloy steel, and the kinetics of the growth process changed parabolically over time. The results of these examination properties of the boride layer as revealed by Optical Microscopy (OP) showed the morphology of the boride layer as a saw-tooth with a thickness ranging from 33 μm to 220 μm depending on the boronizing time. The analysis of Scanning Electron Microscopy (SEM-EDS); showed a distribution of the alloying elements that were detected by Energy Dispersive Spectrometry. The X-ray diffraction (XRD) technique indicated that the surface was a mixture of FeB and Fe2B borides. The evaluation of adhesion of the layers was determined by the technique of Rockwell-C hardness. Young’s modulus and hardness of the layer were evaluated by a nanoindentation technique with a load of 250 mN. The paste dehydrate boriding of micro-alloy reveal a change of properties on the surface; also the coatings FeB and Fe2B, to make a sacrificial function in the steels micro alloyed as widely used in pipelines transporting oil.

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Kinetics of dynamic recrystallization in low - and medium carbon steels during warm ECA pressing

Materials Letters ◽

10.1016/j.matlet.2020.128954 ◽

2021 ◽

Vol 285 ◽

pp. 128954

Author(s):

Natalia Koptseva ◽

Yulia Efimova ◽

Mikhail Chukin ◽

Irina Yakovleva ◽

Aleksander Zhilyaev ◽

...

Keyword(s):

Dynamic Recrystallization ◽

Carbon Steels ◽

Medium Carbon ◽

Medium Carbon Steels ◽

Kinetics Of

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X-Ray Stress Measurements in Ground Surface of Steel by Position Sensitive Detector

Advances in X-ray Analysis ◽

10.1154/s037603080000731x ◽

1980 ◽

Vol 24 ◽

pp. 181-185 ◽

Cited By ~ 1

Author(s):

M. Kawata ◽

M. Morinaga ◽

Y. Yoshioka

Keyword(s):

Residual Stress ◽

Ground Surface ◽

Carbon Steels ◽

Sensitive Detector ◽

Medium Carbon ◽

X Ray ◽

Cylindrical Grinding ◽

Medium Carbon Steels ◽

Grinding Conditions ◽

Position Sensitive

AbstractThe residual stress produced by surface and cylindrical grinding was measured by a position sensitive proportional counter. In medium carbon steels the residual stress depends largely on the grinding conditions. For a gentle cylindrical grinding compressive stress was observed, but for a rough grinding tensile stress was present in the workpiece.

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Effects of Silicon, Chromium, and Copper on Kinetic Parameters of Precipitation during Tempering of Medium Carbon Steels

Materials ◽

10.3390/ma14061445 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1445

Author(s):

Aleksandr Gokhman ◽

Zbyšek Nový ◽

Pavel Salvetr ◽

Vasyl Ryukhtin ◽

Pavel Strunz ◽

...

Keyword(s):

Quantitative Information ◽

Carbon Steels ◽

X Ray Diffraction ◽

Medium Carbon ◽

Copper Precipitation ◽

Transmission Electron ◽

Medium Carbon Steels ◽

Optimal Technology ◽

The Difference ◽

Using Data

Understanding the tempering behavior of medium carbon steels is mandatory if their mechanical properties are to be improved. For an optimal technology to be developed for this purpose, a substantial experimental basis is needed to extract quantitative information on the microstructure of the tempered material. This paper reports on the characterization of microstructural changes induced by tempering in medium-carbon steels alloyed with Si, Cr, Cu, and Mn using state-of-the-art experimental techniques. Complementarities among these techniques are highlighted. The evolution of transition carbides, cementite, and copper precipitates is described using data from X-ray diffraction, small and ultra-small angle neutron diffraction, transmission electron microscopy, and dilatometry observation. The effects of silicon, chromium, and copper on the mechanism of carbide and copper precipitation are discussed. The considerable changes found in the size and volume of copper precipitates correlate well with the difference in the yield stress between tempered steels with and without copper.

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Boriding kinetics of Fe2B layers formed on AISI 1045 steel

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb140323019z ◽

2014 ◽

Vol 50 (2) ◽

pp. 101-107 ◽

Cited By ~ 15

Author(s):

J. Zuno-Silva ◽

M. Ortiz-Domínguez ◽

M. Keddam ◽

M. Elias-Espinosa ◽

O. Damián-Mejía ◽

...

Keyword(s):

Diffusion Model ◽

Diffusion Coefficients ◽

Mass Conservation ◽

Boron Diffusion ◽

X Ray Diffraction ◽

X Ray ◽

Aisi 1045 Steel ◽

Aisi 1045 ◽

1045 Steel ◽

Kinetics Of

In the present work, a diffusion model was suggested to study the growth kinetics of Fe2B layers grown on the AISI 1045 steel by the pack-boriding treatment. The generated boride layers were analyzed by optical microscopy and X-ray diffraction analysis. The applied diffusion model is based on the principle of mass conservation at the (Fe2B/ substrate) interface. It was used to estimate the boron diffusion coefficients of Fe2B in the temperature range of 1123-1273 K. A validation of the model was also made by comparing the experimental Fe2B layer thickness obtained at 1253 K for 5 h of treatment with the predicted value. Basing on our experimental results, the boron activation energy was estimated as 180 kJ mol-1 for the AISI 1045 steel.

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