FABRICATION OF
SOLID CRA PIPING
SPEAKER: FULL NAME
ABU DHABI NATIONAL
OIL ONSHORE
COMPANY
ADNOC
AGENDA
• Common materials & welding consumables used
ADNOC ONSHORE | FABRICATION OF CRA PIPING
• Welding Process and Procedure Qualification - Special
Requirements
• Fabrication of solid CRA at Shop and Site
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• NDT Inspections & acceptance criteria
• Painting
• Lesson Learned
MATERIALS COVERED
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ADNOC ONSHORE | FABRICATION OF CRA PIPING
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INCOLY (825)
Piping components
ASTM B423 UNS N08825 – Pipe
ASTM B366 UNS N08825- Fitting
ASTM B564 UNS N08825.- Flange
INCONEL (625)
Piping Components
ASTM B444 UNS N06625 - Pipe
ASTM B366 UNS N6625- Fitting
ASTM B564 UNS N06625- Flange
SDSS-Cr%25 ASTM A790 Gr. S32750 - Pipe
ASTM A928 Gr. S32750 Welded Pipes Size 6” and greater-Pipe
ASTM A182 F53- Flange
ASTM A815 Gr. S32750 Cl. WP-S, ASTM A815 Gr. S32750 Cl. WP-WX- Fittings
SS
ASTM A312 TP316/316L- Pipe
ASTM A403Gr.WP316/316L-WX - Fitting
ASTM A182 Gr. F316/316L- Flange
Joining of solid CRA Piping Components- Welding
Consumables

Predominantly we Go with ERNiCrMo-3 for Nickel alloy
ADNOC ONSHORE | FABRICATION OF CRA PIPING
(both 625 and 825 material).
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ER2594/ E2594-15 for SDSS
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ER 316L/E316L-15 for SS
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PMI testing to be conducted as per AGES-GL-13-002
ADNOC ONSHORE | FABRICATION OF CRA PIPING
WELDING PROCESS
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ADNOC ONSHORE | FABRICATION OF CRA PIPING
SPECIAL REQUIREMENTS FOR WPQ
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ASTM G28 for 825 (IGC for Cr. Bearing alloy)
ASTM G48 for 625 (Pitting and Crevice Corrosion Resistance test)
ASTM G48 for SDSS (Pitting and Crevice Corrosion Resistance test)
ASTM A262 for SS (Inter Granular Corrosion Test)
ADNOC ONSHORE | FABRICATION OF CRA PIPING
MATERIAL RECEIVING AND STORAGE
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 Materials are received and stored as per the Project
specification Identified by PMI (if required), then color
coded and stored or stacked on a wooden blocks / Racks
with enough ground clearance.
 Pipes are arranged with a protected Bevel ends and
covered from atmospheric exposure.
 Piping components as stored in Warehouse with this
same identification and Bevel end protection.
ADNOC ONSHORE | FABRICATION OF CRA PIPING
FABRICATION OF SOLID CRA WELDING
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•A dedicated Workshop to be assigned for SS and Nickel alloy fabrication isolated from other LTCS/CS materials.
•Tools (Wire brush and grinding wheel to dedicated SS material)
•Joints to be made matching the ID of the piping components
•Prior to start of the welding Oxygen Level is ensured to below 0.05%
•Purging Gas purity to be 99.9%
•Rest Parameters are followed as per the WPS.
•Inter pass Temperature is maintained
70-100 Degree Celsius for SDSS
150 Degree Celsius for SS and Nickel Alloy.
•Heat input are also carefully monitored as per WPS
0.5 to 1.75KJ/mm max for SDSS
2KJ/mm max for Nickel Alloy.
•Inert Gas Purging is maintained for Root and Cold Pass for SS/SDSS/ Nickel piping welding and upto a min. of 6mm deposit thickness.
•Acceptable Level of Oxidation of Root if followed in process as said in DEP 30.10.60.31-Gen. Feb 2013
Unacceptable levels of Root Oxidation
Acceptable levels of weld root oxidations
NDE COVERAGE FOR WELDMENT
ADNOC ONSHORE | FABRICATION OF CRA PIPING
•Upon completion of the joint PMI, PT, hardness and other NDT Requirements
Carried out as per Line class.
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•In addition, Ferrite Content Test to be carried out for SS and SDSS weldment and HAZ
35%-65% for SDSS -100% (AGES-SP-07-007)
3-8 FN for SS-10% per WPS followed on the spool
•NDT Coverage is as per piping material specification
which in turn referred to Project Piping Class.
POST WED ACTIVITIES
Hydro Testing of the solid CRA Spools.
ADNOC ONSHORE | FABRICATION OF CRA PIPING

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Hydrotest is carried out as per the approved Project Specification with
a condition of Chloride levels in water is less than 50ppm followed by
immediate drain and drying.
Painting of CRA Spools

Upon completion of Hydro test the CRA spools is Blast and the
Painted as per Project Painting Procedure. Painting Class LS1 for the
Nickel alloy and SDSS and SS (AGES-SP-07-004)
 In any case painting material should be ZINC free
Spools are identified and tagged throughout till Erection.
LESSON LEARNED 1
Welding nickel alloy pipe to
CRA clad pipe of two different thicknesses
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ADNOC Classification: Internal
Background
in 2021 BIFP project BAB area
6 months after commissioning of the pump suction line of the water disposal tanks.
Leakage was detected in the branches of the main header of this line.
The main header was 6 reduced Tees CS with CRA lining (6 & 4 inches in diameter and 15
& 12 mm thickness).
connected to 6 nickel alloy pipes (4 inches in diameter and 6 mm thickness).
Leak location
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ADNOC Classification: Internal
Cause of the leak:
During installation of the 4" joint,The contractor's pipe fitter had tapered the thick side of the
joint to match the inside diameter of the thin pipe and this operation removed part of the
clad area, exposing the CS to the corrosive fluid and initiating the corrosion mechanism
which then leaked.
4” x 6 mm
Area exposed to
Corrosive fluid
Tapering
plan
6” x 15 mm
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Ni Alloy material
4” x 12 mm
CS/LTCS material
ADNOC Classification: Internal
How to correct:
By using a transition spool (nickel alloy).
This spool is a piece of pipe with the same diameter of the branch (4 inches) and equal to
the thick part (12 mm) and weld it normally from the reduced tee side and make the taper
from the other side to match the thin part.
4” x 12 mm
transition spool
Tapering
plan
6” x 15 mm
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Ni Alloy material
4” x 12 mm
CS/LTCS material
ADNOC Classification: Internal
LESSON LEARNED 2
Nickel Branch connection to clad pipe
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ADNOC Classification: Internal
Background:
In 2014,
one year after the commissioning of the disposal water facility at BAB CDS (Project 1.8), it was
noticed that there were some leaks coming from the connections between the nickel weld-O-lets and
the clad pipes.
After a detailed investigation,
it was found that the contractor had not followed the correct installation procedure and that 365
similar branches would have to be replaced at an estimated cost of US$8 million.
Leak location
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ADNOC Classification: Internal
Cause of leak:
The contractor had drilled the hole without protecting the carbon steel surface with CRA
material, and this surface was exposed to the corrosive fluid and the corrosion mechanism
started and then leaked.
Exposed CS surface
Ni Alloy material
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CS/LTCS material
ADNOC Classification: Internal
The following steps show the correct way to make such a branch (for 2 inch and below):
Step No. 1
Drill a non-through hole, The non-through hole shall be drilled by using CNC machine.
The diameter of the drilled hole shall be at least D+10mm, where D is the inside diameter of
the weld-O-let (as shown in the figure). The outer carbon steel shall be completely peeled
off and the cladding layer shall be fully exposed. To ensure it is free from iron
contamination, the copper sulphate solution shall be applied with a brush to the nickel alloy
area after removing CS. The hole shall be tapered 15 to 20 degrees.
15-20 deg
Ni Alloy material
D+10 mm
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CS/LTCS material
ADNOC Classification: Internal
Step No. 2
Manual Weld Overlay
After Step 1, a manual weld overlay shall be applied to the nickel alloy layer (as shown in
the figure).
Welding shall be carried out using the qualified WPS.
Ni Alloy material
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CS/LTCS material
ADNOC Classification: Internal
Step 3
Drill through hole
Before drilling, the weld reinforcement on the outer surface of the CS pipe shall be ground
flush.
The through hole shall be drilled using a CNC machine.
The diameter of the through hole shall match the ID of the weld-O-let and the minimum wall
thickness of the cladding layer by manual welding overlay shall be 5mm (as shown in the
figure).
Ni Alloy material
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CS/LTCS material
ADNOC Classification: Internal
Step No. 4
Fit up and welding
The connection between the run pipe and the
weld-O-let shall be nickel alloy only (as shown in
the figure).
Before fit up
PT shall be carried out on the weld-O-let hole after
cladding and machining.
Thickness verification shall be performed with a
clad gauge after cladding and machining to verify
the remaining clad thickness.
After fit up
Welding shall be performed with the qualified
WPS.
Ni Alloy material
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CS/LTCS material
THANK YOU
ADNOC ONSHORE