Buying CRA clad or lined pipe without a clear inspection plan is risky. A weak bond, wrong alloy, or missed defect can cause failures in corrosive service that cost far more than the pipe itself. This checklist gives buyers and inspectors a practical framework for verifying clad pipe quality before it leaves the mill.
1. Pre-Production Review
Before manufacturing starts, confirm that the supplier understands and can meet the specification:
- Purchase order matches the approved drawing and specification
- Material grades for base pipe and CRA liner are defined
- Applicable standards are listed (API 5LD, ASME SA-263/264/265, DNV, project-specific)
- Inspection and test plan (ITP) is approved by buyer or third party
- Welding procedure specifications (WPS/PQR) are qualified for clad pipe ends
- Non-destructive testing (NDT) plan is agreed
2. Incoming Material Inspection
Verify that the raw materials match the specification before bonding:
- Base pipe: Mill test report, heat number, chemical composition, mechanical properties, dimensional check
- CRA liner: Mill test report, alloy grade verification (PMI), thickness measurement, surface condition
- Storage: Materials protected from contamination, moisture, and mechanical damage
3. During Production Inspection
Monitor the bonding and fabrication steps that determine final performance:
3.1 Bonding Process Verification
- Bonding parameters recorded (pressure, temperature, time, deformation)
- Process controlled within qualified range
- Visual inspection of bonded interface on sample cuts
3.2 Dimensional Checks
- Outside diameter and wall thickness at multiple locations
- Liner thickness measurement (minimum and average)
- Length, straightness, and out-of-roundness
- End finish: bevel angle, root face, land width
4. Final Testing and NDE
These tests confirm that the finished pipe meets mechanical and bond integrity requirements:
| Test / Inspection | Purpose | Acceptance Criteria |
|---|---|---|
| Ultrasonic Testing (UT) | Detect unbonded areas at the CRA-to-base interface | No unbonded areas exceeding allowable limits per API 5LD |
| Shear Bond Strength Test | Measure mechanical bond strength | ≥ specified minimum (e.g., API 5LD minimum) |
| Hydrostatic Test | Verify pressure integrity of base pipe and bond | No leakage or deformation at test pressure |
| Flattening Test | Check ductility and bond durability | No cracking or delamination at required flattening distance |
| Bend Test | Confirm liner integrity under bending | No cracks, wrinkles, or separation in CRA layer |
| Positive Material Identification (PMI) | Verify CRA alloy grade | Matches specified grade within tolerance |
| Visual Inspection | Check surface defects, end preparation, marking | Free of cracks, gouges, corrosion; marking legible |
5. Documentation Review
Paperwork is as important as the physical pipe. Before shipment, collect:
- Mill Test Report (MTR) for base pipe and CRA liner
- Heat numbers and material certificates with full traceability
- Bond strength test reports
- Ultrasonic testing reports with defect maps
- Hydrostatic test certificates
- NDE inspection reports (UT, RT, MT, PT as applicable)
- Dimensional inspection report
- Third-party inspection release note (if applicable)
- Packing list and shipping documents
6. Pre-Shipment Inspection
- Random sample visual inspection of finished pipes
- Verify marking: grade, size, heat number, standard, manufacturer
- Check end protection caps and sealing
- Confirm packing method prevents moisture ingress and mechanical damage
- Review shipping marks and documentation consistency
7. Red Flags That Should Stop Shipment
- Bond strength values close to or below specification minimum
- Unbonded areas detected by UT in critical zones
- CRA alloy grade does not match PMI results
- Missing or inconsistent heat numbers and traceability records
- Dimensional deviations outside tolerance
- Surface defects, corrosion, or contamination on CRA layer
- Supplier refuses third-party inspection access
8. Conclusion
A structured inspection and quality control process protects buyers from receiving clad pipe that looks correct on paper but fails in service. The most successful projects define the ITP early, witness key tests, and verify documentation traceability before shipment.
ZONX PIPE provides full inspection documentation with every API-5LD clad pipe order, including UT bond inspection reports, hydrostatic test certificates, PMI records, and third-party inspection coordination. Contact us to review a sample quality dossier.