The influence of external and internal factors on stress corrosion cracking of low-alloyed pipe steel
DOI:
https://doi.org/10.31471/2311-1399-2020-1(13)-8-15Keywords:
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.
Downloads
References
Stress corrosion cracking. URL :
https://www.slideshare.net/SHIВAJICHOUDHURY/damagemechanism-
in-boiler-thermal-power-plant (the date of access
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
, ‘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
, ‘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
/25/2014. Nizhny Novgorod: Gazprom VNIIGAZ LLC,
p. (in Russian)
Downloads
Published
How to Cite
Issue
Section
License
Copyright Notice
1.png)
1.png){kind=logo}
