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Studying Stress Corrosion Cracking Crack Initiation in Pipeline Steels in a Near-Neutral pH Environment: The Role of Hydrotesting
- Source :
- Corrosion. 76
- Publication Year :
- 2020
- Publisher :
- NACE International, 2020.
-
Abstract
- Hydrostatic testing, or hydrotesting, has been widely used as a stress corrosion cracking management method in the pipeline industry, particularly in gas pipelines. Although the technique has been very useful in the prevention of operational failures, it is known that these high pressures can produce significant plastic deformation around stress concentrators, such as pits and other surface flaws, that might be present. This plasticity can temporarily retard long, well-developed cracks; however, the effect of this plasticity on growth of very small cracks has not previously been studied. In this work, a long-term test was conducted to simulate real pipeline pressure cycling conditions by the application of occasional hydrotesting loads on steel samples. Crack initiations from pits were compared between specimens undergoing no hydrotesting load (control specimens) and those that underwent three hydrotest cycles during the test. The results showed that pit-to-crack transition was enhanced by the application of three hydrotesting loads. Seventy percent more cracks were found to have grown beyond ferrite grain boundaries in the hydrotested specimens. This initial study indicated substantial differences between small crack formation with and without hydrotesting. These differences predict significantly higher short crack growth in the hydrotested samples. Further study is necessary to further delineate these effects.
- Subjects :
- Materials science
020209 energy
General Chemical Engineering
Metallurgy
02 engineering and technology
General Chemistry
021001 nanoscience & nanotechnology
Pipeline (software)
Pipeline transport
Hydrostatic test
Crack initiation
0202 electrical engineering, electronic engineering, information engineering
General Materials Science
Neutral ph
Stress corrosion cracking
0210 nano-technology
Subjects
Details
- ISSN :
- 1938159X and 00109312
- Volume :
- 76
- Database :
- OpenAIRE
- Journal :
- Corrosion
- Accession number :
- edsair.doi...........c5e410a2514f7137904fc7e2420f84f4