Mechanistic aspects of stress corrosion crack initiation and early propagation

Conference · Mon Nov 01 04:00:00 EST 1999

OSTI ID:697090

Wang, Y Z; Revie, R W ^[1]

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1. CANMET Natural Resources Canada, Ottawa, Ontario (Canada). Materials Technology Lab.

When a material-environment system exhibits an active-passive transition, stress corrosion cracks (SCC) can advance by localized dissolution at the crack tip and remain sharp because passivation of the crack walls prevents lateral dissolution. SCC has been found in high-pressure gas and oil transmission pipelines buried in soils containing ground waters in which the pipeline steels do not show an active-passive transition. The pH values of these solutions are near neutral, pH 7 or slightly lower. In laboratory studies, it has been found that, under these environmental conditions, restricted mechanical loading conditions, either dynamic, continuously straining, or cyclic, are required to induce cracking from initially smooth specimens. It is predominantly the mechanical loading conditions that control the sharpness of cracks. The original intact linepipe surface is more conducive for cracking than is the polished surface. The corrosivity of the solution, in terms of pH, also affects cracking behavior.

• OSTI ID: 697090
• Report Number(s): CONF-990401--
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
03 NATURAL GAS
36 MATERIALS SCIENCE
CARBON STEELS
CORROSIVE EFFECTS
CRACK PROPAGATION
GROUND WATER
NATURAL GAS
PETROLEUM
PH VALUE
PIPELINES
STRESS CORROSION
UNDERGROUND