stress corrosion cracking overview & introduction
DESCRIPTION
Stress Corrosion Cracking Overview & Introduction. David Johnson December 2, 2003. SCC History. Not a recent phenomenon Not exclusive to pipelines Not confined to underground environment Not geographically limited Ammonia cracking of cartridge brass Chloride cracking of stainless steel. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/1.jpg)
Stress Corrosion CrackingOverview & Introduction
David Johnson
December 2, 2003
![Page 2: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/2.jpg)
SCC History
• Not a recent phenomenon
• Not exclusive to pipelines
• Not confined to underground environment
• Not geographically limited
• Ammonia cracking of cartridge brass
• Chloride cracking of stainless steel
![Page 3: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/3.jpg)
Requirements for SCC
Environment
StressMetallurgy
![Page 4: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/4.jpg)
SCC Characteristics
Factor High pH Neutral pH Location CS discharges
Wet-dry soils Aggressive soil
Anywhere Wet-dry soils Aggressive soil
Temperature Exponential temperature impact
Little apparent effect
![Page 5: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/5.jpg)
SCC Characteristics
Factor High pH Neutral pH
Electrolyte Carbonate-bicarbonate pH > 9.3
Dilute bicarbonate 5.5 < pH <7.5 Higher CO2
Potential -600 to –750 mV Free potential
Cracks Intergranular Narrow Not corroded
Transgranular Wider May be corroded
![Page 6: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/6.jpg)
SCC near Seam Weld
![Page 7: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/7.jpg)
Metallography of SCC
![Page 8: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/8.jpg)
ASME Causes of Gas Transmission Incidents
0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0
Vandalism
Stress Corrosion Cracking
Malfunction
Prev. Damgd Pipe
Mfr
Constr/Instal
Other Failures
Unknown
Incorrect Operation
Misc
Natural Forces
Internal Corrosion
External Corrosion
Third Party Damage
Non-Pipe
Pipe
Summary of Incident Causes
![Page 9: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/9.jpg)
Summary of Significance
• Natural gas transmission(1985-2002)– 15 of 1415 total reported incidents
• Liquid transmission (PPTS)– 5 of 472 in database
• NEB (Canada) (1992-2002)– 3 of 23– None since 1995
• Overall - about 1% of incidents
![Page 10: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/10.jpg)
Why Today’s Interest?
• Other, higher significance threats also being addressed
![Page 11: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/11.jpg)
Other Threats (B31.8S)• External Corrosion• Internal Corrosion• Manufacturing Defects• Welding & Fabrication Defects• Equipment Failure• Third Party / Mechanical Damage• Incorrect Operations• Weather & Outside Force
![Page 12: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/12.jpg)
External & Internal Corrosion
• CP systems
• Gas quality standards and monitoring
• Relatively mature ILI capability
• Correlated to hydro-test capability
• Rapidly maturing DA capabilities
![Page 13: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/13.jpg)
Manufacturing & Construction
• Specifications - materials & construction
• Advances in materials technology
• Mill inspections
• Construction inspections
• Proof testing
![Page 14: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/14.jpg)
Third Party Damage
• Dig Safety
• Common Ground Alliance
• One Call enforcement
• Enhanced public awareness
![Page 15: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/15.jpg)
Incorrect Operation
• Operator Qualification programs
• Qualification of controllers
• OQ-2
• B31Q
![Page 16: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/16.jpg)
Equipment Failure
• Gaskets, Seals, Valves, Pumps, etc.
• Generally not pipe
• Generally confined
• Specifications, testing, maintenance
![Page 17: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/17.jpg)
Weather & Outside Forces
• Design & Construction
• Forecasting
• Monitoring
• Better understanding of material responses
![Page 18: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/18.jpg)
Why Today’s Interest?
• Other, higher significance threats also being addressed
• Less apparent understanding
• Small, but widespread, occurrence
• Methods of addressing not as mature– Inspection, characterization, assessment,
management
![Page 19: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/19.jpg)
Today’s Workshop
• Share available information
• Understand application of current management techniques
• Update on R&D
• Future Needs– Technology development– Regulatory approach
![Page 20: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/20.jpg)
Managing SCC
• Operators have found & managed SCC• Tools as prescribed in PLSIA of 2002
– In-Line Inspection– Hydrostatic Testing– Direct Assessment – Other
• All have specific capabilities & limitations• Gas - Liquid Pipeline Differences
![Page 21: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/21.jpg)
Major Challenges
• Finding SCC– Shallow cracks initially– May not be visible to unaided eye
• Gas - Liquid technology differences• Service disruptions• Water disposal• Assessing what is found• Mitigation and Management
![Page 22: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/22.jpg)
Research & Development
• Multi-faceted approach
• Environmental factors
• Surface preparation & coatings
• CP system operation
• Operational factors
• Material behavior
• Detection & sizing
![Page 23: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/23.jpg)
Regulatory Response
• Determining reasonable response
• Setting investigation protocols
• Communication needs
![Page 24: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/24.jpg)
Upcoming Panels
• Operator Experience with Finding and Managing SCC
1. TransCanada
2. Enbridge
3. Kinder Morgan
4. Duke
5. Williams
6. Colonial
![Page 25: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/25.jpg)
Upcoming Panels
• R & D– What’s been done– Current work– Future needs– PRCI– ILIA– NACE
![Page 26: Stress Corrosion Cracking Overview & Introduction](https://reader036.vdocuments.site/reader036/viewer/2022062314/56812ebc550346895d945cf3/html5/thumbnails/26.jpg)
Upcoming Panels
• Regulators– Concerns & Needs– NEB– EUB– MNOPS– USDOT-OPS