In this paper, crack growth behaviour and the crack tip chemistry of X70 pipeline steel in the near-neutral pH environment were investigated using the in-situ measurements. The stress corrosion crack propagated forward under the cyclic load, with a mean crack growth rate (CGR) of 4.28 × 10–3 mm/cycle. The CGR da/dN obeys well with the stress corrosion fatigue mechanism. During the crack propagation, the crack tip environment differed significantly from the bulk solution. An aggressive electrolyte with low pH (about 4.0) and high concentration of Cl– (about 3.8 M) was produced near the crack tip. These results provided the direct evidence for simulating the crack tip solution and investigating the crack tip anodic dissolution.
ParkinsR. N.: ‘A review of stress corrosion cracking of high pressure gas pipelines’, Corrosion20002000Paper No. 00363, Orlando.
2.
LiM. C. and ChengY. F.: ‘Mechanistic investigation of hydrogen-enhanced anodic dissolution of X-70 pipe steel and its implication on near-neutral pH SCC of pipelines’, Electrochim. Acta200752, (28), 8111–8117. doi: 10.1016/j.electacta.2007.07.015
3.
GuB.LuoJ. and MaoX.: ‘Hydrogen-facilitated anodic dissolution-type stress corrosion cracking of pipeline steels in near-neutral pH solution’, Corrosion199955, (1), 96–106. doi: 10.5006/1.3283971
4.
LiuZ. Y.LiX. G. and ChengY. F.: ‘In-situ characterization of the electrochemistry of grain and grain boundary of an X70 steel in a near-neutral pH solution’, Electrochem. Commun.201012, (7), 936–938. doi: 10.1016/j.elecom.2010.04.025
5.
LuB. T.LuoJ. L. and NortonP. R.: ‘Environmentally assisted cracking mechanism of pipeline steel in near-neutral pH groundwater’, Corros. Sci.201052, (5), 1787–1795. doi: 10.1016/j.corsci.2010.02.020
6.
WangL. W.DuC. W.LiuZ. Y.WangX. H. and LiX. G.: ‘Influence of carbon on stress corrosion cracking of high strength pipeline steel’, Corros. Sci.201376486–493. doi: 10.1016/j.corsci.2013.06.051
7.
LiuZ. Y.LiX. G. and ChengY. F.: ‘Mechanistic aspect of near-neutral pH stress corrosion cracking of pipelines under cathodic polarization’, Corros. Sci.20125554–60. doi: 10.1016/j.corsci.2011.10.002
8.
TurnbullA.DolphinA. and RackleyF.: ‘Experimental determination of the electrochemistry in corrosion fatigue cracks in structural steel in artificial seawater’, Corrosion198844, (1), 55–61. doi: 10.5006/1.3582026
9.
BrownB.FujiiC., and DahlbergE. P.: ‘Methods for studying the solution chemistry within stress corrosion cracks’, J. Electrochem. Soc.1969116, (2), 218–219. doi: 10.1149/1.2411799
10.
AndresenP. and YoungL.: ‘Crack tip microsampling and growth rate measurements in low-alloy steel in high-temperature water’, Corrosion199551, (3), 223–233. doi: 10.5006/1.3294365
11.
PageR.McMinnA. and HudakS.JR: ‘Characterization of crack tip electrochemistry using a simulated crack’, Corrosion198844, (9), 623–631. doi: 10.5006/1.3584975
12.
DmytrakhI.: ‘Corrosion fracture of structural metallic materials: Effect of electrochemical conditions in crack’, Strain201147, (S2), 427–435. doi: 10.1111/j.1475-1305.2010.00784.x
13.
CooperK. R. and KellyR.: ‘Crack tip chemistry and electrochemistry of environmental cracks in AA 7050’, Corros. Sci.200749, (6), 2636–2662. doi: 10.1016/j.corsci.2006.12.001
14.
ASTM E647: ‘Standard test method for fatigue crack growth rates’, 2005, Philadelphia, The American Society for Testing of Materials.
15.
DuffJ. and MarrowT.: ‘In situ observation of short fatigue crack propagation in oxygenated water at elevated temperature and pressure’, Corros. Sci.20136834–43. doi: 10.1016/j.corsci.2012.10.030
16.
KamayaM. and HarunaT.: ‘Influence of local stress on initiation behavior of stress corrosion cracking for sensitized 304 stainless steel’, Corros. Sci.200749, (8), 3303–3324. doi: 10.1016/j.corsci.2007.01.011
17.
WangX. Z.LiuZ. Y.GeX.ZhanX. L.DuC. W. and LiX. G.: ‘Growth Behavior of Stress Corrosion Cracks of X80 Pipeline Steel in Underground Water of Acidic Soil’, Corrosion201470872–879. doi: 10.5006/1094
ParkinsR. N. and BeaversJ. A.: ‘Some effects of strain rate on the transgranular stress corrosion cracking of ferritic steels in dilute near-neutral-pH solutions’, Corrosion200359, (3), 258–273. doi: 10.5006/1.3277559
20.
BeaversJ. A. and JaskeC. E.: ‘Near-neutral pH SCC of pipelines: Effects of pressure fluctuations on crack propagation’, Corrosion199898Paper No. 00257, San Diego.
21.
BeaversJ. A.OwenD. M.DurrC. L.DelantyB. and SutherbyR.: ‘Near neutral pH SCC: Crack propagation in susceptible oil environments’, Corrosion2001Paper No. 01217, Houston.
22.
ChenW. and SutherbyR. L.: ‘Crack growth behavior of pipeline steel in near-neutral pH soil environments’, Metallurg. Mater. Transa. A200738, (6), 1260–1268. doi: 10.1007/s11661-007-9184-8
23.
RogowskaM.GudmeJ.RubinA.PantleonK. and AmbatR.: ‘Effect of Fe ion concentration on fatigue life of carbon steel in aqueous CO2 environment’, Corros. Eng. Sci. Technol.2015, doi: 10.1179/1743278215Y.0000000035
24.
EadieR.SzklarzK. and SutherbyR.: ‘Corrosion fatigue and near-neutral pH stress corrosion cracking of pipeline steel and the effect of hydrogen sulfide’, Corrosion200561, (2), 167–173. doi: 10.5006/1.3278171
25.
AndersonT. L. and OsageD. A.: ‘API 579: A comprehensive fitness-for-service guide’, Int. J. Press. Vessels Piping200077, (14), 953–963. doi: 10.1016/S0308-0161(01)00018-7
26.
BeaversJ. A.: ‘2013 Frank Newman Speller Award Lecture: Integrity management of natural gas and petroleum pipelines subject to stress corrosion cracking’, Corrosion201370, (1), 3–18. doi: 10.5006/0998
27.
TurnbullA.: ‘The solution composition and electrode potential in pits, crevices and cracks’, Corros. Sci.198323, (8), 833–870. doi: 10.1016/0010-938X(83)90014-8
28.
SathlerL. and van MuylderJ.: ‘ CEBELCOR Rapports Techniques’, report, 1974.
29.
FujiiC.: ‘Electrochemical and chemical aspects of localized corrosion’, Cebelcor,1974.
30.
ParkinsR. N.BlanchardW.JR and DelantyB.: ‘Transgranular stress corrosion cracking of high-pressure pipelines in contact with solutions of near neutral pH’, Corrosion199450, (5), 394–408. doi: 10.5006/1.3294348
31.
KingF.JackT. R.ChenW.WilmottM. J.FesslerR. R. and KristK.: ‘Mechanistic studies of initiation and early stage crack growth for near-neutral pH SCC on pipelines’, Corrosion 20002000Paper No. 00361, Orlando.
32.
ZhaoW.XinR.HeZ. and WangY.: ‘Contribution of anodic dissolution to the corrosion fatigue crack propagation of X80 steel in 3.5 wt.% NaCl solution’, Corros. Sci.201263387–392. doi: 10.1016/j.corsci.2012.06.016
