Effect of CO2 and R-ratio on near-neutral pH stress corrosion cracking initiation under a disbonded coating of pipeline steel

The effects of soil type of Shanghai and electrode potential from cathodic protection point on near-neutral pH stress corrosion cracking (SCC) behavior of pipeline steel X60 has been investigated for structural integrity assessment. The SCC behavior was evaluated through slow strain rate tests (SSRT) at various electrode potentials in three solutions containing different typical soils. Results showed that the SCC susceptibility generally increased with decreasing electrode potential in all the three environments, with quick increase happening in the range from-1500 to-700mV(SCE). It is suggested that hydrogen induced cracking should dominate the SCC at low potentials. In cathodic potential range, the rank of the SCC susceptibility for soil type was Near-city soil > Cyan-purple soil > Cyan-yellow soil. In anodic potential range, SCC susceptibility curves mixed each other in the three solutions.

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A mechanistic study on near-neutral pH stress corrosion cracking of pipeline steel

Environment-Induced Cracking of Materials ◽

10.1016/b978-008044635-6.50062-5 ◽

2008 ◽

pp. 243-253 ◽

Cited By ~ 3

Author(s):

B.T. Lu ◽

J.L. Luo

Keyword(s):

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Pipeline Steel ◽

Corrosion Cracking ◽

Mechanistic Study ◽

Neutral Ph ◽

Ph Stress

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Fundamentally understanding the effect of Non-stable cathodic potential on stress corrosion cracking of pipeline steel in Near-neutral pH solution

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123117 ◽

2021 ◽

Vol 288 ◽

pp. 123117

Author(s):

Zhong Li ◽

Baozhuang Sun ◽

Qi Liu ◽

Yifan Yu ◽

Zhiyong Liu

Keyword(s):

Stress Corrosion ◽

Stress Corrosion Cracking ◽

Pipeline Steel ◽

Corrosion Cracking ◽

Cathodic Potential ◽

Neutral Ph

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

Volume 2: Integrity Management; Poster Session; Student Paper Competition ◽

10.1115/ipc2006-10544 ◽

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.

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