The mechanism of hydrogen-facilitated anodic-dissolution-type stress corrosion cracking: theories and experiments

2001 ◽  
Vol 81 (7) ◽  
pp. 1813-1831 ◽  
Author(s):  
S. X. Mao ◽  
B. Gu ◽  
N. Q. Wu ◽  
L. Qiao
Keyword(s):  
Stress Corrosion ◽  
Anodic Dissolution ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking

Modeling the Interactions of Hydrogen, Stress and Dissolution in Near-Neutral pH Stress Corrosion Cracking of Pipelines

2006 ◽  
Author(s):  
Frank Y. Cheng
Keyword(s):  
Stress Corrosion ◽  
Dissolution Rate ◽  
Crack Growth ◽  
Anodic Dissolution ◽  
Hydrogen Concentration ◽  
Stress Corrosion Cracking ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
Neutral Ph ◽  
Ph Stress

A thermodynamic model was developed to determine the interactions of hydrogen, stress and anodic dissolution at the crack-tip during near-neutral pH stress corrosion cracking in pipelines. By analyzing the free-energy of the steel in the presence and absence of hydrogen and stress, it is demonstrated that a synergism of hydrogen and stress promotes the cracking of the steel. The enhanced hydrogen concentration in the stressed steel significantly accelerates the crack growth. The quantitative prediction of the crack growth rate in near-neutral pH environment is based on the determination of the effect of hydrogen on the anodic dissolution rate in the absence of stress, the effect of stress on the anodic dissolution rate in the absence of hydrogen, the synergistic effect of hydrogen and stress on the anodic dissolution rate at the crack-tip and the effect of the variation of hydrogen concentration on the anodic dissolution rate.

Hydrogen Facilitated Anodic Dissolution Type Stress Corrosion Cracking of Pipeline Steels in Coating Disbondment Chemistry

1998 ◽  
Author(s):  
Scott X. Mao ◽  
J. L. Luo ◽  
B. Gu ◽  
W. Yu
Keyword(s):  
Stress Corrosion ◽  
Anodic Dissolution ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Strain Rates ◽  
Pipeline Steels ◽  
Dilute Aqueous Solution ◽  
Sims Analysis ◽  
Cracking Process ◽  
Secondary Ion

The stress corrosion cracking (SCC) of pipeline steels in coating disbondment chemistry (near neutral pH solution) was studied by using slow strain rate tests (SSRT), polarization techniques, SEM and SIMS (secondary ion mass spectroscope). It was found that SCC susceptibility increased as the applied electrochemical potential and strain rates decreased. Hydrogen (H) precharging or addition of CO2 facilitated the process of SCC, suggesting that dissolution and hydrogen ingress are involved in the cracking process. SIMS analysis showed that hydrogen could diffuse into steels around the crack tip during the SCC process, which would facilitate the dissolution rate of the steel and increase SCC susceptibility. A mechanism was proposed which shows that hydrogen enhances anodic dissolution type of SCC in dilute aqueous solution. A thermodynamic analysis of the SCC process was carried out, and was found to be consistent with the experimental results.

Influence of Mooring Chain Steel Strength on Stress Corrosion Cracking

2013 ◽  
Vol 404 ◽  
pp. 32-39 ◽  
Author(s):  
Xiao Ying Cheng ◽  
Hong Yuan Chen ◽  
Wen Qing Liu ◽  
Zhi Juan Zhang
Keyword(s):  
Hydrogen Embrittlement ◽  
Stress Corrosion ◽  
Failure Mechanism ◽  
Anodic Dissolution ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Lower Strength ◽  
Synthetic Seawater ◽  
Steel Strength ◽  
Mooring Chain

Two strength mooring chain steels were used to investigate the stress corrosion cracking (SCC) in synthetic seawater. The resistance of both strength steels to SCC was similar in neutral synthetic seawater. But the failure mechanism was different. For lower strength steel, it is mainly induced by anodic dissolution, while for higher strength steel, by hydrogen embrittlement. The reason was elucidated from their microstructures and corrosion characteristics.

Effect of Potentials on Stress Corrosion Cracking of X80 Pipeline Steel in Simulated Soil Solution

2011 ◽  
Vol 197-198 ◽  
pp. 1549-1554 ◽  
Author(s):  
Yuan Cheng ◽  
Hong Ying Yu ◽  
Ying Wang ◽  
Xu Meng ◽  
Li Xin Zhang ◽  
...  
Keyword(s):  
Strain Rate ◽  
Stress Corrosion ◽  
Soil Solution ◽  
Anodic Dissolution ◽  
Stress Corrosion Cracking ◽  
Fracture Mechanism ◽  
Pipeline Steel ◽  
Corrosion Cracking ◽  
X80 Pipeline Steel ◽  
X80 Steel

The stress corrosion cracking (SCC) susceptibility of X80 pipeline steel, which was used in the Second West-East Gas Pipeline, was investigated in simulated soil solution of Xinzhou in Hubei province of China. The SCC susceptibility was studied using the slow strain rate tensile (SSRT) tests in which different potentials were applied. The fracture surfaces were observed using SEM. X80 steel was susceptible to SCC in simulated solution. The SCC was not serious with the anodic potentials applied. The fracture mechanism was anodic dissolution. But the SCC was affected obviously with different cathodic potentials because of the different influence of the hydrogen.

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