Chris Fowler the Vice President of NACE speaks about Sour Service Testing of Girth Welds during his presentation at 3rd Annual Corrosion management Summit 2008 in Abu Dhabi. After the success of the last Corrosion Management event in October 2008, Corrosion Management Summit is back and scheduled to take place from 11th – 14th October 2009 in Abu Dhabi. The key focus of this year’s summit will be the latest successful techniques enabling you to optimize your corrosion management practices to prevent spills, plant shutdown, loss of income and production. For more info visit www.corrosionmanagementme.com

1. Sour Service Testing of Girth
Welds
Dr Chris Fowler FIMMM
Global Director Bodycote Corrosion

2. The Four Point Bend Test
History
ASTM G39
ISO 7539-2
Homogeneous Prismatic Samples
Loaded by Deflection
Elastic Region only.
slide number 2

3. The Four Point Bend Test
History
EFC 16 (Carbon Steels)
Shows weld root intact sample.
Longitudinal and Transverse.
Mentions Strain Gauging
slide number 3

4. The Four Point Bend Test
History
EFC 17
Implies root intact sample
Provides Strain Gauge Formulae.
slide number 4

5. The Four Point Bend Test
NACE TM0177(Carbon Steels & CRA’s)
Mentions Four Point Bends as an
supplementary test.
WG085f
Tasked with writing a test procedure.
slide number 5

6. The Four Point Bend Test
NACE MR0175 / ISO 15156
(Carbon Steels & CRA’s)
4PB test method included for carbon steels (80 / 90%
AYS) and CRA’s (100% AYS)
Evaluation of carbon steels for SSC not well defined
(refers to NACE TM0177!)
Evaluation method for 4PB carbon steels detailed for
SOHIC and SZC and NOT SSC.
Evaluation of CRA’s for SSC and SCC not well defined
(refers to NACE TM0177 and EFC 17).
slide number 6

7. The Four Point Bend Test
Reality
Weld Root intact
NON Homogenous
Curved
With miss-match
Thickness (FEA)
slide number 7

8. The Four Point Bend Test
Reality
Carbon Steel v CRA’s
Ambient Temperature
High Temperature
slide number 8

9. The Four Point Bend Test
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10. The Four Point Bend Test
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11. The Four Point Bend Test
Loading Issues (1)
80% & 90% AYS!!!
Compensates for loss of Residuals?
NOT ALL IN THE SAME DIRECTION
What is the AYS?
Tensile data or Flexural 4pt bend?
slide number 11

12. The Four Point Bend Test
Loading Issues (2)
Strain Gauge Location
Strain distribution across width and length
Miss-match
Load Stability
slide number 12

13. The Four Point Bend Test
Evaluation
No standard practice.
New section in EFC 16
EFC 17-x10 & SEM or Metallography
Not covered by either TM0177 or ISO 15156
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14. The Four Point Bend Test
Historically
Loaded 72% SMYS
Elastic Region
Now
Used as Weld Qualification
At high % AYS
Possible Plastic Zone
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15. The Four Point Bend Test
The Way Forward
Scrap the Test!
Recognise the Test limitations
Write a comprehensive test procedure.
New workgroup under EFC charged with
producing a procedure.
Review LOADING LEVELS.
or
THE FULL RING TEST
slide number 15

16. The Full Ring Test
Published by the UK Health & Safety
Executive as
OTI 95-635
Included in ISO15156/NACE MR0175 as an
option
slide number 16

17. The Full Ring Test
Description
A Test method which simulates worst case
conditions but with a touch or reality
A method which qualifies linepipe material
and associated welds for use in Sour Service.
Verified against Full Scale Pressure Tests.
slide number 17

18. The Full Ring Test
Schematic(1)
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19. The Full Ring Test
Schematic(2)
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20. The Full Ring Test
Load Considerations
Pipe loaded to the level of maximum DESIGN
Loaded in the direction of the field applied
stress.
Edge effects avoided.
Variation in AYS not important
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21. The Full Ring Test
Residual Stress
Residual stress from pipe manufacture
retained
Residual stress from welding retained
Residual stress from repairs retained
Residual strain from pipe bending retained
No guess at the compensation for loss of
residual stress required.
slide number 21

22. The Full Ring Test
Weld Repairs
Root repair can be included
Full thickness repair can be included.
Can be conducted at elevated temperature.
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23. The Full Ring Test
Monitoring
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24. The Full Ring Test
Sample Selection
Full Pipe section tested
More material tested
Avoids randomness of selection
slide number 24

25. The Full Ring Test
Projects
BP Miller
Mobil Beryl
Bluestream
ADCO – various
Agip
Chevron
Statoil
slide number 25

26. The Full Ring Test
Overall Advantages
A realistic test
Simulates the Field Conditions
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27. The Full Ring Test
Conclusions
•NO loss of residual stress/strain
•Applied load in the correct direction
•NO sample selection problems
•Girth weld and repair can be included.
•Genuine surface exposed to the environment.
•Controlled loading
slide number 27

28. The Full Ring Test
The Real Test
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29. The Full Ring Test
The Real Test
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30. The Full Ring Test
Acknowledgements
Conoco Phillips
BP
ADCO
Technip
Bluestream
To name but a few!
slide number 30