scholarly journals Diffusible Hydrogen Concentration in Draw Arc Stud Weldments

ce/papers ◽  
2021 ◽  
Vol 4 (2-4) ◽  
pp. 2481-2487
Author(s):  
Oliver Brätz ◽  
Knuth‐Michael Henkel
Keyword(s):  
Hydrogen Concentration ◽  
Diffusible Hydrogen

Effects of Environmental Factors on Hydrogen Absorption and Sulfide Stress Cracking Susceptibility of Low Alloy Steel

CORROSION ◽  
10.5006/3414 ◽  
2020 ◽  
Vol 76 (7) ◽  
pp. 698-706
Author(s):  
Kenji Kobayashi ◽  
Tomohiko Omura ◽  
Shinji Fujimoto
Keyword(s):  
Environmental Factors ◽  
Partial Pressure ◽  
Hydrogen Concentration ◽  
Critical Stress Intensity Factor ◽  
Low Alloy Steels ◽  
Diffusible Hydrogen ◽  
Solution Ph ◽  
Stress Cracking ◽  
Sulfide Stress ◽  
Sulfide Stress Cracking

In this study, the sulfide stress cracking (SSC) susceptibility of high-strength low alloy steels was investigated quantitatively. Double cantilever beam tests were used to evaluate the effects of environmental factors, namely pH, H2S partial pressure, and temperature, on the SSC. The corrosion rates and the absorbed diffusible hydrogen concentration were also determined. The critical stress intensity factor (KISSC), which signifies the SSC susceptibility, was mainly affected by the H2S partial pressure and the temperature. Even though the solution pH apparently affected the corrosion rate, the influence of pH on KISSC was small. Considering these results, the environmental contribution in each elementary process of the SSC phenomenon was discussed. The estimated local hydrogen concentration at the crack tip area, which clearly depends on H2S partial pressure and temperature, showed good correlation to the KISSC obtained in various sour conditions.

Effects of Hydrogen Concentration, Specimen Thickness and Loading Frequency on the Hydrogen Enhanced Crack Propagation of Low Alloy Steel

2011 ◽  
Vol 465 ◽  
pp. 519-522
Author(s):  
Yoshiyuki Kondo ◽  
Koshiro Mizobe ◽  
Masanobu Kubota
Keyword(s):  
Crack Propagation ◽  
Alloy Steel ◽  
Hydrogen Concentration ◽  
Crack Propagation Rate ◽  
Propagation Rate ◽  
Specimen Thickness ◽  
Loading Frequency ◽  
Low Alloy Steel ◽  
Diffusible Hydrogen ◽  
Thin Specimen

Crack propagation of SCM440H low alloy steel under varying load is enhanced by absorbed hydrogen. Substantial acceleration of crack propagation rate up to 1000 times was observed compared with that of uncharged material. The role of factors affecting enhanced acceleration was investigated by changing hydrogen concentration absorbed in metal, specimen thickness and loading frequency. Results are as follows. (1) 0.2 mass ppm diffusible hydrogen in metal was enough to cause enhanced acceleration. The predominant fracture mode showing acceleration was quasi cleavage. (2) In the case of thin specimen thinner than 0.8mm, the tri-axiality of stress is weak, and the enhanced crack propagation did not appear. However, the introduction of side-groove to 0.8mm specimen in order to increase the tri-axiality resulted in enhanced acceleration. (3) Lower loading frequency resulted in higher crack propagation rate in cycle domain. The crack propagation rate in time domain was almost constant irrespective of loading frequency. Enough concentration of hydrogen, tri-axiality and low loading frequency resulted in enhanced acceleration of fatigue crack propagation.

scholarly journals Hydrogen Concentration Distribution in 2.25Cr-1Mo-0.25V Steel under the Electrochemical Hydrogen Charging and Its Influence on the Mechanical Properties

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2263 ◽  
Author(s):  
Changdong Yin ◽  
Jianjun Chen ◽  
Dongdong Ye ◽  
Zhou Xu ◽  
Jiahao Ge ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Concentration ◽  
Hydrogen Absorption ◽  
Concentration Distribution ◽  
Hydrogen Permeation ◽  
Diffusible Hydrogen ◽  
Saturation State ◽  
Hydrogen Charging ◽  
Charging Time ◽  
And Diffusion

The deterioration of the mechanical properties of metal induced by hydrogen absorption threatens the safety of the equipment serviced in hydrogen environments. In this study, the hydrogen concentration distribution in 2.25Cr-1Mo-0.25V steel after hydrogen charging was analyzed following the hydrogen permeation and diffusion model. The diffusible hydrogen content in the 1-mm-thick specimen and its influence on the mechanical properties of the material were investigated by glycerol gas collecting test, static hydrogen charging tensile test, scanning electron microscopy (SEM) test, and microhardness test. The results indicate that the content of diffusible hydrogen tends to be the saturation state when the hydrogen charging time reaches 48 h. The simulation results suggest that the hydrogen concentration distribution can be effectively simulated by ABAQUS and the method can be used to analyze the hydrogen concentration in the material with complex structures or containing multiple microstructures. The influence of hydrogen on the mechanical properties is that the elongation of this material is reduced and the diffusible hydrogen will cause a decrease in the fracture toughness of the material, and thus hydrogen embrittlement (HE) will occur. Moreover, the Young’s modulus E and microhardness are increased due to hydrogen absorption, and the variation value is related to the hydrogen concentration introduced into the specimen.

Hydrogen concentration monitoring in subsoil air on tectonic faults on the territory adjacent to NPP

2016 ◽  
Vol 2016 (2) ◽  
pp. 163-171
Author(s):  
Georgij Konstantinovich Ignatenko ◽  
Pyotr Ivanovich Gremchenko ◽  
Yurij Mihajlovich Glushkov
Keyword(s):  
Hydrogen Concentration ◽  
Tectonic Faults

Control of hydrogen absorption by nickel films obtained upon magnetic spraying of zirconium alloy using the thermoEMF method

2020 ◽  
Vol 86 (8) ◽  
pp. 32-37
Author(s):  
V. V. Larionov ◽  
Xu Shupeng ◽  
V. N. Kudiyarov
Keyword(s):  
Magnetron Sputtering ◽  
Hydrogen Concentration ◽  
Hydrogen Absorption ◽  
Zirconium Alloy ◽  
Hydrogen Adsorption ◽  
Zirconium Alloys ◽  
Nickel Film ◽  
Protective Film ◽  
Nickel Films ◽  
Hydrogen Penetration

Nickel films formed on the surface of zirconium alloys are often used to protect materials against hydrogen penetration. Hydrogen adsorption on nickel is faster since the latter actively interacts with hydrogen, oxidizes and forms a protective film. The goal of the study is to develop a method providing control of hydrogen absorption by nickel films during vacuum-magnetron sputtering and hydrogenation via measuring thermoEMF. Zirconium alloy E110 was saturated from the gas phase with hydrogen at a temperature of 350°C and a pressure of 2 atm. A specialized Rainbow Spectrum unit was used for coating. It is shown that a nickel film present on the surface significantly affects the hydrogen penetration into the alloy. A coating with a thickness of more than 2 μm deposited by magnetron sputtering on the surface of a zirconium alloy with 1% Nb, almost completely protects the alloy against hydrogen penetration. The magnitude of thermoemf depends on the hydrogen concentration in the zirconium alloy and film thickness. An analysis of the hysteresis width of the thermoEMF temperature loop and a method for determining the effective activation energy of the conductivity of a hydrogenated material coated with a nickel film are presented. The results of the study can be used in assessing the hydrogen concentration and, hence, corrosion protection of the material.

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