Mechanisms of High-pH and Near-Neutral-pH SCC of Underground Pipelines

Beavers, J.A.; Harle, Brent A.

doi:10.1115/1.1376716

Cited by 72 publications

(25 citation statements)

References 4 publications

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“…SCC has been recognized as a cause of failure since the 60's especially in gas pipelines that handle crude oil and natural gas at high pressures [6]. Buried pipelines usually show two types of SCC according to the pH: 1) SCC of high pH (9)(10)(11)(12), also known as classic SCC, and 2) SCC of low pH (6)(7)(8), also known as SCC of pH close to neutral. SCC in steels is related with two types of cracking: which are transgranular cracking (TGSCC) and intergranular cracking (IGSCC) and in some cases it occurs in mixed mode [7,8].…”

Section: Introductionmentioning

confidence: 99%

Stress corrosion cracking assessment of API X65 steel non‐conventionally heat treated

Natividad

Garcı́a

López

et al. 2015

Materials & Corrosion

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Stress corrosion cracking (SCC) susceptibility of API X65 steel nonconventionally heat-treated was evaluated through slow strain rate tests (SSRTs) using the synthetic soil solution NS4 at 20, 40 and 60 8C. Polarization curves (PCs) and corrosion potential (E corr ) measurements were also performed. The non-conventional heat treatment (HT) was made by heating plates at 1050 8C for 30 min followed by water quenching. The tensile strength of the heat-treated plates increased to values similar to API X80 steel. The SCC index obtained by ratios of mechanical properties indicated that X65 steel without HT is not susceptible to SCC whereas with HT is slightly susceptible to SCC. The SCC mechanism in the soil solution in the heat-treated plates was influenced by hydrogen diffusion as confirmed by the internal cracks and the brittle fracture observed in the specimens. The electrochemical study suggests that the corrosion process of X65 steel with and without HT occurs via a mix mechanism where the charge transfer resistance is influenced by a mass transfer process. Crevice corrosion features were found in the surface of the steel. It is likely that this type of corrosion could have sensitized the X65 steel and induced cracks when the steel was under tensile stress.

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Section: Introductionmentioning

confidence: 99%

Stress corrosion cracking assessment of API X65 steel non‐conventionally heat treated

Natividad

Garcı́a

López

et al. 2015

Materials & Corrosion

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“…A dissolution mechanism dominated the initial growing stage but was subsequently followed by HIC, consistent with results by Beavers and Harle. 8 The loading-displacement curves in the inert environment were close; at the turning points both of them were much higher than that in the solution environment. The crack growth rates (CGR) at fi ve test conditions all fl uctuated during the crack growth process.…”

Section: Discussionmentioning

confidence: 93%

Growth Behavior of Stress Corrosion Cracks of X80 Pipeline Steel in Underground Water of Acidic Soil

Wang¹,

Liu²,

Ge³

et al. 2014

CORROSION

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The growth behavior of stress corrosion cracks of X80 pipeline steel in the underground water of acidic soil environments was investigated by a slow-rate-loading crack growth test, electrochemical polarization curves, electrochemical impedance spectroscopy, and scanning electron microscopy. Crack growth mechanism was mixed-controlled by both anodic dissolution and hydrogen involvement. Ductile cracking first occurred and crack growth was primarily based on the anodic dissolution mechanism. Crack propagation gradually changed from ductile cracking to brittle cracking. Crack growth rate significantly accelerated with decreasing solution pH; crack propagation followed a hydrogen-based mechanism during the quick crack propagation stage.

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“…5,11,17 The issue is whether AD or HIC dominates the crack-ing process of pipeline steel in near-neutral pH solution.…”

Section: Discussionmentioning

confidence: 99%

“…Many efforts have been made to understand the mechanism of SCC in this nonclassical environment. [5][6][7][8][9][10][11][12][13] The studies have focused mainly on the effect of electrochemical potential and solution composition. However, the considerable scatter in data and the limited research are not enough to explain the nature of SCC in areas of coating disbondment.…”

Section: Introductionmentioning

confidence: 99%

Transgranular Stress Corrosion Cracking of X-80 and X-52 Pipeline Steels in Dilute Aqueous Solution with Near-Neutral pH

Luo

et al. 1999

CORROSION

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Slow strain rate tests (SSRT) and fractographic examination of X-80 and X-52 pipeline steels showed transgranular stress corrosion cracking (TGSCC) could occur in a dilute aqueous solution with near-neutral pH. SCC intensity increased as the applied electrochemical potential and strain rates decreased.Hydrogen precharging or addition of carbon dioxide (CO 2 ) facilitated the process of SCC, suggesting that dissolution and hydrogen ingress were involved in the cracking process.

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Mechanisms of High-pH and Near-Neutral-pH SCC of Underground Pipelines

Cited by 72 publications

References 4 publications

Stress corrosion cracking assessment of API X65 steel non‐conventionally heat treated

Stress corrosion cracking assessment of API X65 steel non‐conventionally heat treated

Growth Behavior of Stress Corrosion Cracks of X80 Pipeline Steel in Underground Water of Acidic Soil

Transgranular Stress Corrosion Cracking of X-80 and X-52 Pipeline Steels in Dilute Aqueous Solution with Near-Neutral pH

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