The role of hydrogen in EAC of pipeline steels in near-neutral pH environments

Been, Jenny; Lu, H.; King, Fraser; Jack, Thomas; Sutherby, Robert

doi:10.1016/b978-008044635-6.50063-7

Cited by 3 publications

(4 citation statements)

References 13 publications

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“…Moreover, the hydrogen concentration at the crack tip position would be more elevated due to the strain concentration in front of the crack tip, which was also reported in the literature [23]. The aspects of hydrogen embrittlement in the cracking process have been studied by others [22,24]. Therefore, the crack extension of 20#, X60, and X80 steels in a near-neutral pH environment can be a result of the combined action of anodic dissolution and hydrogen-induced embrittlement.…”

Section: Scc Mechanism Of 20# X60 and X80 Steels In A Near-neutral Ph...mentioning

confidence: 54%

“…J. Been et al [22] measured the hydrogen concentration of polished and mill scaled X65 by a hydrogen permeation test of 0.73 mol/m 3 and 0.38 mol/m 3 , respectively. Moreover, the hydrogen concentration at the crack tip position would be more elevated due to the strain concentration in front of the crack tip, which was also reported in the literature [23].…”

Section: Scc Mechanism Of 20# X60 and X80 Steels In A Near-neutral Ph...mentioning

confidence: 99%

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Microstructural Effects in the Development of Near-Neutral pH Stress Corrosion Cracks in Pipelines

Zhang

Ran

Wang³

et al. 2022

Materials

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The corrosion and stress corrosion cracking (SCC) behaviors of 20#, X60, and X80 pipeline steels in a near-neutral pH environment were investigated by means of electrochemical measurement, immersion test, and interrupted slow strain rate tensile (SSRT) test. The propensity for SCC, as indicated by the stress threshold value for crack initiation, was found to be dependent on the type of steel microstructure. Cracks were initiated in the high-strength steel X80 at a stress less than its yield strength, whereas in the other lower-grade steels, the initiation of cracks occurred after the yielding point. The threshold stress of SCC initiation in the near-neutral pH environment for 20#, X60, and X80 steels were 130.64% σys, 106.79% σys, and 86.92% σys, respectively. The SCC of 20# and X60 were characterized by the formation of transgranular and intergranular cracks, while X80 steel was only by transgranular cracking. The occurrence of corrosion had a great effect on crack initiation and the growth at the later stage. The latter involved hydrogen effects. A correlation between SCC sensitivity and the yield strength of the steel has been identified.

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Section: Scc Mechanism Of 20# X60 and X80 Steels In A Near-neutral Ph...mentioning

confidence: 54%

Section: Scc Mechanism Of 20# X60 and X80 Steels In A Near-neutral Ph...mentioning

confidence: 99%

Microstructural Effects in the Development of Near-Neutral pH Stress Corrosion Cracks in Pipelines

Zhang

Ran

Wang³

et al. 2022

Materials

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“…This occurs, for example, through galvanic corrosion at phase boundaries [12,14] or at mill scale/steel interfaces. [22,23] Nevertheless, a pre-existing axial crack would come to a dormant state under a monotonic loading in nearneutral pH environments. In fact, mild mechanical cycling in near-neutral pH environments would also lead to crack dormancy, as is demonstrated in Figure 4(b).…”

Section: Existing Growth Modelsmentioning

confidence: 99%

Crack Growth Behavior of Pipeline Steel in Near-Neutral pH Soil Environments

Chen

Sutherby

2007

Metall Mater Trans A

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This article reports the crack growth behavior of X-65 pipeline steel in near-neutral pH environments. Although it is often referred to as stress corrosion cracking (SCC), the crack growth behavior of pipeline steels in near-neutral pH environments has been found to be consistent with that of true corrosion fatigue, and the crack growth rate da/dN can be correlated with DK 2 K max f 0:1 . This correlation enables the determination of threshold DK 2 K max f 0:1 values that demarcate the boundary between active growth and dormancy. Crack tip blunting was observed when a loading condition gave a DK 2 K max f 0:1 value below the threshold. The threshold is found to be environmentally sensitive, and possibly also material dependent, but the details are yet to be determined.

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“…The transgranular quasi-cleavage crack appearance has often been identified as an indication of a role for hydrogen in the crack growth mechanism. The latter, in turn, will facilitate anodic dissolution [3]. However, corrosion rates can only account for field crack growth rates in the order of 10 -8 mm/s under very high strain rates, which are not common in operating pipelines.…”

Section: Crack Growth Mechanismsmentioning

confidence: 99%