Susceptibility of modern ERW pipe to selective weld seam corrosion in wet environments. Final report

Technical Report · Sun Feb 01 04:00:00 EST 1998

OSTI ID:325718

Lukezich, S J

Grooving corrosion is a phenomenon by which the weld seam of electric resistance welded (ERW) pipe is preferentially attacked in wet natural gas environments containing CO{sub 2}. The attack initiates as an aligned string of pits which grow and intersect, forming a round-bottomed groove of damage centered on the weld seam. The susceptibility of ERW pipe to this damage mechanism is known to be related to the chemical composition (particularly the sulfur content) of the pipe, the welding process employed, and the use of a post weld heat treatment. Of particular concern to the natural gas pipeline industry is the fact that at the present time there are no effective means for predicting the susceptibility of a specific lot of ERW pipe to grooving corrosion, prior to placing the pipeline in service. The objective of this program, therefore, is to begin the development of an accelerated laboratory test technique which may be useful as a screening test to establish the susceptibility of an ERW weld to grooving corrosion. A stepped potential, potentiostatic electrochemical test method was used to evaluate the susceptibility of ERW welds from five different pipe samples to grooving corrosion in environments representative of natural gas production. Based on these results, it can be concluded that electrochemical test methods are a promising technique for accelerated screening of ERW weld seam susceptibility to grooving corrosion. Future work in this area should focus on refining the test conditions which provide the most accurate differentiation, and then transition to a testing system which can be conducted at ambient pressures, and preferably without the need for an electronic potentiostat.

• Research Organization: Southwest Research Inst. (United States)
• Sponsoring Organization: American Gas Association, Inc., Arlington, VA (United States)
• OSTI ID: 325718
• Report Number(s): AGA--99001928; CNN: Contract PR-15-9306
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
36 MATERIALS SCIENCE
CARBON DIOXIDE
CARBON STEELS
CORROSION
DIAGNOSTIC TECHNIQUES
NATURAL GAS
PIPELINES
PROGRESS REPORT
RESISTANCE WELDING
WELDED JOINTS