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EEMUA Publication 234: Copper-Nickel Alloy Piping for Offshore Applications – Tubes
Ordering Information
When ordering Cu-Ni tubes per EEMUA 234, the following should be specified:
- Alloy designation (e.g., 90/10 Cu-Ni, 70/30 Cu-Ni)
- Dimensions (outer diameter, wall thickness, length)
- Temper (e.g., annealed, as-drawn)
- End finishes (plain, beveled, grooved)
- Certification requirements (e.g., EN 10204 3.1/3.2)
- Special testing (if required, e.g., corrosion testing)
Material Codes & Alloys
Common alloys covered:
- 90/10 Cu-Ni (UNS C70600) – General seawater service
- 70/30 Cu-Ni (UNS C71500) – Higher corrosion resistance
- Other variants (if applicable, with trace element controls)
Manufacturing & Chemical Composition
- Melting process: Typically electric furnace with controlled impurity levels.
- Chemical composition: Limits for Cu, Ni, Fe, Mn, and trace elements to ensure corrosion resistance.
Mechanical Properties
- Tensile strength, yield strength, elongation per alloy and temper.
- Hardness requirements (Rockwell or Vickers, as applicable).
Dimensional Tolerances
- Outside diameter, wall thickness, straightness, and length tolerances specified.
- Surface finish requirements (e.g., smooth, free from defects).
Inspection & Testing Requirements
- Non-destructive testing (NDT): Eddy current, ultrasonic, or hydrostatic testing.
- Corrosion testing (if specified, e.g., ASTM G48 for pitting resistance).
- Visual inspection for surface defects.
- Certification: Mill test reports (MTRs) to EN 10204 3.1 or 3.2.
Marking & Packaging
- Permanent marking with alloy grade, heat number, size, and manufacturer.
- Protective packaging to prevent damage during transport.
Compliance & Certification
- Compliance with ASTM, EN, or other international standards as applicable.
- Third-party inspection (if required by purchaser).
Conclusion
EEMUA 234 provides a comprehensive specification for Cu-Ni alloy tubes in offshore environments, ensuring material integrity through strict chemical, mechanical, and inspection criteria. It is widely referenced in the oil & gas, marine, and desalination industries.
Material Codes in EEMUA 234 (Latest Version)
1. Common Copper-Nickel Alloys
The standard typically includes the following alloys, identified by Unified Numbering System (UNS) and European (EN) designations:
| Alloy Type | UNS Number | EN Designation | Common Name |
| 90/10 Cu-Ni | UNS C70600 | CW 352H (EN 12451) | 90% Cu, 10% Ni |
| 70/30 Cu-Ni | UNS C71500 | CW 354H (EN 12451) | 70% Cu, 30% Ni |
2. Additional Referenced Standards
EEMUA 234 may also refer to material specifications from:
- ASTM B466 / B467 (Seamless & Welded Cu-Ni Tubes)
- ISO 13388 (Copper & Copper Alloys – Inspection & Testing)
- EN 12451 (Copper & Cu Alloy Tubes for Heat Exchangers)
3. Material Condition (Temper)
- Annealed (O) – Soft condition for forming
- As-Drawn (H) – Hard temper for higher strength
4. Traceability & Certification
- Heat numbers must be provided for material traceability.
- Certification per EN 10204 3.1 or 3.2 (Inspection Certificates).
Key Notes
- The 90/10 Cu-Ni (C70600) is most common for general seawater service.
- The 70/30 Cu-Ni (C71500) offers superior corrosion resistance for harsh offshore conditions.
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