pipeline scc
Post on 29-Jun-2015
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Pipeline SCC – 1
John A. Beavers, Ph.D., FNACE
External SCC of Pipelines
Pipeline SCC – 2
Pipeline SCC – 3
Pipeline SCC – 4
Environment
Material Stress
Pipeline SCC – 5
SCC
Pipeline SCC – 6
Two Forms of SCC
High-pH (Classical) SCC
Near-Neutral-pH (Low-pH) SCC- pH refers to electrolyte beneath disbonded
coating, not soil pH
Pipeline SCC – 7
Characteristics ofBoth Forms of SCC
The dark area on the fracture surface indicates the extent of the crack before it was broken open
Pipeline SCC – 8
Pipeline SCC – 9
High-pH SCC
Photomicrograph showing high-pH stress corrosion crack.
Pipeline SCC – 10
Near-Neutral-pH SCC
Photomicrograph showing near neutral pH stress corrosion crack
Pipeline SCC – 11
External SCC Integrity Management
Three tools commonly used: Direct assessment Hydrostatic testing In-line Inspection
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