Combination of conditions causes stress-corrosion cracking

Journal Article · Mon Feb 16 04:00:00 EST 1976 · Oil Gas J.; (United States)

OSTI ID:5903282

Fessler, R R

Under the sponsorship of the Pipeline Research Committee of the American Gas Association, research at Battelle's Columbus Laboratories has determined that stress-corrosion cracking of buried steel pipelines occurs when the steel is exposed to carbonate-bicarbonate solutions, when the electrode potential is within a narrow range, and when the stress is high enough. Sodium carbonate and sodium bicarbonate are formed when carbon dioxide from the soil reacts with hydroxyl ions produced at the pipe by the action of the cathodic protection currents. Cracking occurs over a wide range of solution compositions but not with pure carbonate solutions that contain no bicarbonate. The other factors responsible are stress fluctuations, which can greatly reduce the threshold stress; partial surface decarburization, which facilitates the start of cracks; high temperature, which hastens the crack growth rate; and the defective coatings, which allow water and a small amount of cathodic current to pass through but prevent escape of the alkaline water and inhibit the cathodic protection system. Failure-prevention techniques are being investigated, but the best approach has not yet been identified.

• OSTI ID: 5903282
• Journal Information: Oil Gas J.; (United States), Journal Name: Oil Gas J.; (United States) Vol. 74; ISSN OIGJA
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
032000* -- Natural Gas-- Transport
Handling
& Storage
ACID CARBONATES
CARBON COMPOUNDS
CARBONATES
CHEMICAL REACTIONS
CORROSION
CORROSIVE EFFECTS
CRACKS
NATURAL GAS DISTRIBUTION SYSTEMS
OXYGEN COMPOUNDS
PIPELINES
STRESS CORROSION
UNDERGROUND SPACE