Assessment of the effects of surface preparation and coatings on the susceptibility of line pipe to stress-corrosion cracking

Technical Report · Mon Feb 24 00:00:00 EST 1992

OSTI ID:6799002

Beavers, J A ^[1]

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1. Cortest Columbus Technologies, Inc., OH (United States)

Objectives were to evaluate susceptibility of pipeline steel to SCC when coated with coal-tar enamel, fusion-bonded epoxy (FBE), and polyethylene tape coatings. The tests included standard cathodic disbondment tests, potential gradients beneath disbonded coatings, electrochemical measurements, and SCC tests. It was concluded that factors affecting relative SCC susceptibility of pipelines with different coatings are the disbonding resistance of the coating and the ability of the coating to pass cathodic protection (CP) current. FBE coated pipelines would be expected to exhibit good SCC resistance, since the FBE coating had high cathodic disbonding resistance and could pass CP current. Grit blasting at levels used at coating mills may be beneficial or detrimental to SCC susceptibility. Excellent correlation was found between th Almen strip deflection and change in SCC threshold stress. It appears to be beneficial to remove as much mill scale as possible, and a white surface finish probably should also be specified. 50 figs, 10 tabs.

• Research Organization: American Gas Association, Inc., Arlington, VA (United States). Pipeline Research Committee; Cortest Columbus Technologies, Inc., OH (United States)
• Sponsoring Organization: AGA; American Gas Association, Inc., Arlington, VA (United States)
• OSTI ID: 6799002
• Report Number(s): AGA-93007094; CNN: Project 186-917; TRN: 93-005037
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
03 NATURAL GAS
PIPELINES
CATHODIC PROTECTION
PROTECTIVE COATINGS
CRACKS
DESCALING
ENAMELS
EPOXIDES
NATURAL GAS DISTRIBUTION SYSTEMS
POLYETHYLENES
PROGRESS REPORT
STEELS
SURFACE TREATMENTS
ALLOYS
COATINGS
CORROSION PROTECTION
DOCUMENT TYPES
IRON ALLOYS
IRON BASE ALLOYS
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANIC POLYMERS
POLYMERS
POLYOLEFINS
SURFACE FINISHING
360105* - Metals & Alloys- Corrosion & Erosion
032000 - Natural Gas- Transport
Handling
& Storage