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

Technical Report · Mon Feb 24 04:00:00 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
• Country of Publication: United States
• Language: English

Related Subjects

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