The influence of external and internal factors on stress corrosion cracking of low-alloyed pipe steel

Authors

  • L. I. Nyrkova

DOI:

https://doi.org/10.31471/2311-1399-2020-1(13)-8-15

Keywords:

alternating wetting; cathodic polarization; low alloyed pipe steel; near-neutral environment; slow strain rate test; stress-corrosion cracking.

Abstract

The article presents investigation results of the regularities of stress corrosion cracking (SCC) of controllable rolling X70 pipeline steel under the influence of various factors: corrosion-active environment, potential, pre-accumulated stresses, periodic wetting, etc. Factors, acting in the conditions of the gas pipe mains operation, were simulated in the laboratory conditions and their influence on the SCC susceptibility of X70 pipe steel was investigated. It was found that in NS4 solution, potential shifting to the cathode area promotes the increasing of the SCC susceptibility of X70 steel. Under cathodic protection at potential equal to -1.0 V, the fracture characteristics change, a brittle component appears in the fracture, and the coefficient KS increases compared to the breaking of samples without cathodic potential. Under such a potential there may appear some differences in the SCC susceptibility of X70 steel, which have a minor structural features: steel with less contamination of non-metallic inclusions is less susceptible to brittle cracking. Accumulated cyclic stresses, periodic wetting, the presence of coatings with different transient resistance and the stress concentrator promote the increase of the degree of SCC susceptibility of X70 pipeline steel at a potential of -1.0 V.

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References

Stress corrosion cracking. URL : https://www.slideshare.net/SHIВAJICHOUDHURY/damagemechanism-in-boiler-thermal-power-plant (the date of access 07.02.2020)

Glazov, NP, Glazov, NG & Bashaev, MA 2009, ‘The influence of the insulation state of pipelines on the rate of their corrosion failure’, Pipeline transport (theory and

practice), no 1, pp. 47–49.

Maocheng, Y, Wang, J, Han, E & Ke, W 2008, ‘Local environment under simulated disbonded coating on steel pipelines in soil solution’, Corrosion Science, vol. 50, iss. 5, pp. 1331–1339.

Eslami, A at all 2010, ‘Stress corrosion cracking initiation under the disbonded coating of pipeline steel in nearneutral pH environment’, Corrosion Science, vol. 52, iss. 11, pp. 3750–3756.

Harris, NA, Ismagilov, NG & Bakhtegareeva, AN 2010, ‘Changes in the thermophysical characteristics of soil around a large-diameter gas pipeline as a reason for the

intensification of corrosion processes’, Oil and Gas Business, iss. 1, pp. 1–9. URL: http://www.ogbus.ru. 2010.

Liu, ZY, Li, XG, Du, CW & Cheng, YF 2009, ‘Local additional potential model for effect of strain rate on SCC of pipeline steel in an acidic soil solution’, Corrosion Science,

vol. 51, iss. 12, pp. 2863–2871.

Liu, ZY, Li, XG, Du, CW, Zhai, GL & Cheng, YF 2008, ‘Stress corrosion cracking behavior of X70 pipe steel in an acidic soil environment’, Corrosion Science, vol. 50, iss. 8, pp. 2251–2257.

Fu, AQ, Tang, X & Cheng, YF 2009, ‘Characterization of corrosion of X70 pipeline steel in thin electrolyte layer under disbonded coating by scanning Kelvin probe’, Corrosion Science, vol. 51, iss. 1, pp. 186–190.

Liu, ZY, Li, NG & Cheng, YF 2012, ‘Mechanistic aspect of near-neutral pH stress corrosion cracking of pipelines under cathodic polarization’, Corrosion Science, vol. 55, iss. 2, pp. 54–60.

Shipilov, SA & Le May, I 2006, ‘Structural integrity of aging buried pipelines having cathodic protection’, Engineering Failure Analysis, no 13, pp. 1159–1176.

Fu, AQ & Cheng, YF 2010, ‘Electrochemical polarization behaВior of X70 steel in thin

carbonate/bicarbonate solution layers trapped under a disbonded coating and its implication on pipeline SCC’, Corrosion Science, vol. 52, iss. 7, pp. 2511–2518.

Khizhnyakov, VI 2009, ‘Prevention of hydrogen evolution when choosing the cathodic protection potential of underground steel pipelines’, Corrosion: materials, protection, no 9, pp. 7–10.

Liu, ZY, Li, NG & Cheng, YF 2012, ‘Mechanistic aspect of near-neutral pH stress corrosion cracking of pipelines under cathodic polarization’, Corrosion Science, vol. 55, iss. 2, pp. 54–60.

Spiridovich, EA 2014, Improving the reliability of gas pipelines in conditions of stress corrosion cracking: the Doctor of Technical Sciences thesis: 25.00.19: defended on 12/25/2014. Nizhny Novgorod: Gazprom VNIIGAZ LLC, 442 p. (in Russian)

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Published

2020-06-29

How to Cite

Nyrkova, L. I. (2020). The influence of external and internal factors on stress corrosion cracking of low-alloyed pipe steel. JOURNAL OF HYDROCARBON POWER ENGINEERING, 7(1), 8–15. https://doi.org/10.31471/2311-1399-2020-1(13)-8-15