Hydrogen Diffusion and Susceptibility to Hydrogen Embrittlement in HSLA Steel Cathodically Polarized under Potentiostatic Control

2003 ◽  
Vol 2003 (0) ◽  
pp. 785-786
Author(s):  
Shinichi Komazaki ◽  
Tatsuhiro Honno ◽  
Toshihei Misawa
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
Hsla Steel

Microstructure Imaging, Precipitation Formation and Mechanical Properties: Al–Li and Al–Mg–Zn Alloys

2019 ◽  
Author(s):  
Wilfried Wunderlich ◽  
Janos Lendvai ◽  
Hans-Joachim Gudladt
Keyword(s):  
Hydrogen Embrittlement ◽  
Driving Force ◽  
Hydrogen Diffusion ◽  
Nano Particles ◽  
Peak Hardness ◽  
Free Zone ◽  
The Third ◽  
Transmission Electron ◽  
Moisture Conditions ◽  
Precipitation Formation

This article describes concepts of three features of microstructure–properties relationship, first the imaging and formation of nano-particles, then their contribution to hardness, and finally hydrogen embrittlement during fatigue. First, we briefly review the imaging modes in transmission electron microscopy (TEM) for nano-sized precipitates. The next issue is the hardening in Aluminum alloys, which is caused by GP-zones or precipitates, formed at the second step of the annealing process. After homogenization, the peak-hardness can be generally achieved by a few hours of annealing between 120°C and 200°C. Hardness measurements and equal-channel axial pressing (ECAP) showed that even at room temperature the driving force for formation of the particles is so strong that already within one hour of annealing after homogenization a remarkable hardening occurs. The third issue, hydrogen embrittlement, is caused by oxidation of pure Al surfaces produced at the crack tip during fatigue under ambient or wet moisture conditions. The cracks propagate preferentially along the precipitation free zone adjacent to grain boundaries, where hydrogen diffusion is fastest.

Investigation of hydrogen diffusion behavior in 12Cr2Mo1R(H) steel by electrochemical tests and first-principles calculation

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiang Qiu ◽  
Kun Zhang ◽  
Qin Kang ◽  
Yicheng Fan ◽  
Hongyu San ◽  
...  
Keyword(s):  
Activation Energy ◽  
Diffusion Coefficient ◽  
Hydrogen Atom ◽  
Hydrogen Embrittlement ◽  
First Principles ◽  
Hydrogen Diffusion ◽  
First Principles Calculations ◽  
Content Type ◽  
Diffusion Behavior ◽  
Hydrogen Diffusion Coefficient

Purpose This paper aims to study the mechanism of hydrogen embrittlement in 12Cr2Mo1R(H) steel, which will help to provide valuable information for the subsequent hydrogen embrittlement research of this kind of steel, so as to optimize the processing technology and take more appropriate measures to prevent hydrogen damage. Design/methodology/approach The hydrogen diffusion coefficient of 12Cr2Mo1R(H) steel was measured by the hydrogen permeation technique of double electrolytic cells. Moreover, the influence of hydrogen traps in the material and experimental temperature on hydrogen diffusion behavior was discussed. The first-principles calculations based on density functional theory were used to study the occupancy of H atoms in the bcc-Fe cell, the diffusion path and the interaction with vacancy defects. Findings The results revealed that the logarithm of the hydrogen diffusion coefficient of the material has a linear relationship with the reciprocal of temperature and the activation energy of hydrogen atom diffusion in 12Cr2Mo1R(H) steel is 23.47 kJ/mol. H atoms stably exist in the nearly octahedral interstices in the crystal cell with vacancies. In addition, the solution of Cr/Mo alloy atom does not change the lowest energy path of H atom, but increases the diffusion activation energy of hydrogen atom, thus hindering the diffusion of hydrogen atom. Cr/Mo and vacancy have a synergistic effect on inhibiting the diffusion of H atoms in α-Fe. Originality/value This article combines experiments with first-principles calculations to explore the diffusion behavior of hydrogen in 12Cr2Mo1R(H) steel from the macroscopic and microscopic perspectives, which will help to establish a calculation model with complex defects in the future.

Role of Residual Stresses and Strains Fields Generated by Heat Treatments on the Hydrogen Embrittlement of a Nuclear Reactor Pressure Vessel

2011 ◽  
Author(s):  
J. Toribio ◽  
D. Vergara ◽  
M. Lorenzo ◽  
J. J. Marti´n
Keyword(s):  
Hydrogen Embrittlement ◽  
Pressure Vessel ◽  
Nuclear Reactor ◽  
Hydrogen Diffusion ◽  
Operation Time ◽  
Heat Treatments ◽  
Reactor Pressure Vessel ◽  
Low Carbon ◽  
Tempering Temperature ◽  
Reactor Pressure

The wall of a nuclear reactor pressure vessel can undergo a reduction of its mechanical properties due to the presence of hydrogen, a process known as hydrogen embrittlement (HE). A numerical model of hydrogen diffusion assisted by stress and strain was used in this paper to evaluate the HE process in the wall of a real nuclear reactor pressure vessel, formed by a bimaterial (stainless steel and low carbon steel). In this sense, a quantitative analysis was carried out of the influence of tempering heat treatments conditions applied to these two steels on hydrogen concentration accumulated in the nuclear reactor vessel during its operation time. To this end, the most relevant parameters of these heat treatments were considered: (i) tempering temperature and (ii) tempering time.

The characteristics of hydrogen diffusion and concentration around a crack tip concerned with hydrogen embrittlement

2002 ◽  
Vol 44 (3) ◽  
pp. 407-424 ◽  
Author(s):  
A.Toshimitsu Yokobori ◽  
Yasrou Chinda ◽  
Takenao Nemoto ◽  
Koji Satoh ◽  
Tetsuya Yamada
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
Crack Tip

Ductile Tearing Prediction in Welds Considering Hydrogen Embrittlement

2013 ◽  
Author(s):  
Vincent Robin ◽  
Philippe Gilles ◽  
Philippe Mourgue ◽  
David Tchoukien
Keyword(s):  
Residual Stress ◽  
Hydrogen Embrittlement ◽  
Energy Release Rate ◽  
Energy Release ◽  
Release Rate ◽  
Crack Front ◽  
Hydrogen Diffusion ◽  
Critical Energy ◽  
Critical Energy Release Rate ◽  
Welding Operation

Some flaws may appear in metal components, in the weld region, and more especially in the case of electron beam girth weld in the slope area of the process (start and stop of the welding operation). These initial flaws can growth with delay even without any external loads. Indeed close to the junction, the material undergoes the combination of high tensile residual stresses due to welding operation and the presence of hydrogen brought by manufacturing process. Hydrogen assisted cracking is then suspected to explain the origin of crack growth through hydrogen embrittlement of the base metal. To understand by numerical modeling, at least qualitatively, the scenario of appearance of such cracks and their evolution, without any external load or under pressure load, the proposed approach consists first in simulating the welding process and its consequences on residual stress distribution and hydrogen concentrations [1]. The hydrogen diffusion computation is pursued after the welding operation simulation in order to highlight the most critical moment at which macroscopic defects may appear. Then, a macroscopic defect is created in the so determined critical zone, the stability of which is studied by estimating the energy release rate at the crack front and by comparing these values with experimental data such as the critical energy release rate at initiation and the tearing resistance curves which may depend on the hydrogen content. So, it is numerically possible to propagate the defect in the time, considering hydrogen diffusion and residual stress rebalancing, by successive crack front definition performed as the crack tip region exceeds the critical energy release rate [14]. Finally, the evolution of the defect is estimated in the same way under pressure test loading conditions. Results and discussions are presented to propose an engineering approach for the design assessment of such specific weld junctions with a low and hydrogen dependant toughness.

scholarly journals Hydrogen Embrittlement and Diffusion in High Strength Low Alloyed Steels with Different Microstructures

2018 ◽  
Author(s):  
Marina Cabrini ◽  
Sergio Lorenzi ◽  
Diego Pesenti Bucella ◽  
Tommaso Pastore
Keyword(s):  
Hydrogen Embrittlement ◽  
Strain Rate ◽  
Hydrogen Diffusion ◽  
High Strength Steels ◽  
High Strength ◽  
Tempered Martensite ◽  
Hsla Steels ◽  
And Diffusion ◽  
Embrittlement Resistance ◽  
Hydrogen Embrittlement Resistance

<span lang="EN-US">The paper deals with the effect of microstructure on the hydrogen diffusion in traditional ferritic-pearlitic HSLA steels and new high strength steels, with tempered martensite microstructures or banded ferritic-bainitic-martensitic microstructures. Diffusivity was correlated to the hydrogen embrittlement resistance of steels, evaluated by means of slow strain rate tests.</span>

scholarly journals Hydrogen Diffusion and Its Effect on Hydrogen Embrittlement in DP Steels With Different Martensite Content

2020 ◽  
Vol 7 ◽  
Author(s):  
Zhen Wang ◽  
Jing Liu ◽  
Feng Huang ◽  
Yun-jie Bi ◽  
Shi-qi Zhang
Keyword(s):  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
Hydrogen Permeation ◽  
Hydrogen Atoms ◽  
Martensite Content ◽  
Measurement Results ◽  
Dp Steels ◽  
Logarithmic Relationship ◽  
Diffusion Of Hydrogen ◽  
Effective Hydrogen

The hydrogen diffusion behavior and hydrogen embrittlement susceptibility of dual phase (DP) steels with different martensite content were investigated using the slow strain-rate tensile test and hydrogen permeation measurement. Results showed that a logarithmic relationship was established between the hydrogen embrittlement index (IHE) and the effective hydrogen diffusion coefficient (Deff). When the martensite content is low, ferrite/martensite interface behaves as the main trap that captures the hydrogen atoms. Also, when the Deff decreases, IHE increases with increasing martensite content. However, when the martensite content reaches approximately 68.3%, the martensite grains start to form a continuous network, Deff reaches a plateau and IHE continues to increase. This is mainly related to the reduction of carbon content in martensite and the length of ferrite/martensite interface, which promotes the diffusion of hydrogen atoms in martensite and the aggregation of hydrogen atoms at the ferrite/martensite interface. Finally, a model describing the mechanism of microstructure-driven hydrogen diffusion with different martensite distribution was established.

Experimental and Molecular Dynamics Simulation Based Investigations on Hydrogen Embrittlement Behavior of Chromium Electroplated 4340 Steel

2021 ◽  
pp. 1-32
Author(s):  
Ozge Dogan ◽  
Mehmet Fazil Kapci ◽  
Volkan Esat ◽  
Burak Bal
Keyword(s):  
Molecular Dynamics ◽  
Hydrogen Embrittlement ◽  
Hydrogen Diffusion ◽  
Dynamics Simulation ◽  
Tensile Response ◽  
4340 Steel ◽  
Similar Chemical ◽  
Simulation Based ◽  
Chromium Electroplating ◽  
Electroplating Process

Abstract In this study chromium electroplating process, corresponding hydrogen embrittlement and the effects of baking on hydrogen diffusion are investigated. Three types of materials in the form of Raw 4340 steel, Chromium electroplated 4340 steel, and Chromium electroplated & baked 4340 steel are used in order to shed light into the aforementioned processes. Mechanical and microstructural analyses are carried out to observe the effects of hydrogen diffusion. Mechanical analyses show that tensile strength and hardness of the specimens deteriorate after chrome-electroplating process due to the presence of atomic hydrogen. XRD analyses are carried out for material characterization. Microstructural analyses reveal that hydrogen enters into the material with chromium electroplating process, and baking after chromium electroplating process is an effective way to prevent hydrogen embrittlement. Additionally, effects of hydrogen on the tensile response of ?-Fe based microstructure with similar chemical composition of alloying elements are simulated through Molecular Dynamics (MD) method.

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