Seamless Copper Nickel 90/10 Pipe
What is a Seamless Copper Nickel 90/10 Pipe?
Seamless Copper Nickel 90/10 Pipe (UNS C70600, roughly 90 % copper with 10 % nickel plus 1–1.8 % iron) is a marine-grade alloy pipe produced from a solid billet without a welded seam. It is the most widely used copper-nickel alloy for seawater systems.
The controlled iron addition enhances the protective corrosion-product film, giving C70600 excellent resistance to seawater corrosion, biofouling and stress-corrosion cracking. Its natural anti-fouling behavior — marine organisms do not readily attach — keeps cooling systems clean without chlorination in many services.
Manufactured to ASTM B466/B467 and related standards, 90/10 copper-nickel seamless pipe is the standard material for shipboard seawater piping, offshore platform fire mains, and coastal power-plant cooling circuits.
Copper Nickel 90/10 vs 70/30 vs Admiralty Brass vs Titanium in Seawater
For seawater piping, the classic comparison is between the two cupro-nickels, brass and titanium. Each occupies a distinct cost-performance point.
| Grade | Key Chemistry / Condition | Where It Fits |
|---|---|---|
| CuNi 90/10 (C70600) | 10 % Ni, 1.4 % Fe | The economic seawater standard; excellent antifouling, 0.5-2.0 m/s design velocities |
| CuNi 70/30 (C71500) | 30 % Ni, 0.6 % Fe | Higher strength and velocity capability (to ~3 m/s) for offshore and naval systems |
| Admiralty brass | Cu-Zn-Sn | Lower cost but vulnerable to dezincification and ammonia attack in polluted harbours |
| Titanium Gr.2 | Commercially pure Ti | Ultimate seawater performance at several times the cost and with no antifouling effect |
Product Specifications
Specification data for Seamless Copper Nickel 90/10 Pipe is compiled from the governing ASTM/ASME/EN standards and our routine production records; typical values are shown where a standard leaves a limit open.
| Category | Standard / Designation |
|---|---|
| Seamless Pipe & Tube | ASTM B466 / ASME SB466 |
| Welded Pipe | ASTM B467 / ASME SB467 |
| Condenser & Heat-Exchanger Tube | ASTM B111 / B552 |
| UNS Designation | C70600 |
| Werkstoff Number | 2.0872 (CuNi10Fe1Mn) |
| Military Standard | MIL-T-16420 (equivalent chemistry) |
Size and Weight Chart
| OD (mm) | Typical Wall (mm) | Weight (kg/m) |
|---|---|---|
| 15.9 | 1.0 | 0.42 |
| 19.05 | 1.2 | 0.6 |
| 25.4 | 1.5 | 1.0 |
| 31.8 | 1.5 | 1.27 |
| 38.1 | 2.0 | 2.02 |
| 50.8 | 2.0 | 2.73 |
| 63.5 | 2.5 | 4.26 |
| 76.2 | 3.0 | 6.14 |
| 101.6 | 3.5 | 9.6 |
| 152.4 | 4.5 | 18.61 |
| 219.1 | 5.5 | 32.85 |
The table lists typical production sizes with a common wall for each diameter; the full dimensional programme of the governing standard is available, and intermediate diameters, walls and lengths are cut to order.
Chemical Composition
| Element | Min (%) | Max (%) |
|---|---|---|
| Copper (Cu) | Balance | — |
| Nickel (Ni) | 9.0 | 11.0 |
| Iron (Fe) | 1.0 | 1.8 |
| Manganese (Mn) | — | 1.0 |
| Zinc (Zn) | — | 1.0 (max, residual) |
| Lead (Pb) | — | 0.05 (max, residual) |
Mechanical Properties
| Property | Value |
|---|---|
| Tensile Strength (typical, annealed) | 300 MPa (43.5 ksi) |
| Yield Strength (0.2 % offset, typical) | 110 MPa (16 ksi) |
| Elongation in 2 in. / 50 mm (typical) | 40 % |
| Hardness (typical, annealed) | ≤ 110 HBW |
| Condition | Annealed; half-hard temper available for higher pressure ratings |
Physical Properties
| Property | Value |
|---|---|
| Density | 8.90 g/cm³ |
| Melting Range | 1100 – 1145 °C |
| Elastic Modulus | 130 GPa |
| Coefficient of Thermal Expansion (20–100 °C) | 17.0 µm/m·°C |
| Thermal Conductivity (at 20 °C) | 40 – 50 W/m·K |
| Specific Heat Capacity | 377 J/kg·K |
| Electrical Resistivity | 144 nΩ·m |
Equivalent Grades
| Standard System | Designation |
|---|---|
| UNS | C70600 |
| Werkstoff Nr. | 2.0872 |
| EN | CuNi10Fe1Mn / CW352H |
| ASTM | B466 / B111 / B467 |
Why 90/10 Copper Nickel Is the Shipboard Standard
C70600 has earned four decades of shipboard and coastal-plant service for three combined reasons. First, its naturally protective cuprous-oxide film with iron enrichment resists general and pitting corrosion in flowing, aerated seawater. Second, the same surface chemistry is mildly toxic to marine organisms, so the tube resists biofouling without chlorination dosing — a maintenance saving no plastic or titanium line can claim. Third, the alloy conducts heat well and is easy to fabricate and flange, keeping installed cost below every alternative with comparable life.
Correct velocity management is the key to its longevity: at design flows up to about 2 m/s the protective film remains intact for decades, which is why 90/10 dominates ship seawater cooling, ballast and fire-main systems. Our C70600 seamless tube is produced to ASTM B466/B111 with controlled 0.8-1.5 % iron — the micro-alloying that makes the film self-repairing.
Manufacturing Process
Our seamless production route for Seamless Copper Nickel 90/10 Pipe follows these documented stages:
- Melting & Casting: Electrolytic copper, nickel and iron are melted and cast into sound cylindrical billets with tight control of Fe and Mn micro-alloying.
- Hot Extrusion / Piercing: Billets are hot-extruded or cross-pierced into seamless tubes, giving a dense, inclusion-free wall.
- Cold Drawing: Cold-drawing passes achieve final OD and wall with smooth bore and OD surfaces.
- Intermediate & Final Annealing: Annealing at about 650-750 °C between passes and after the final pass restores softness and stabilizes the single-phase structure.
- Pickling & Cleaning: Tubes are acid-pickled and rinsed to a clean, bright copper-nickel surface ready for shipboard installation.
- Testing: Hydrostatic testing, eddy-current examination and tensile verification are completed on every batch before release.
Surface Finish Options
- Pickled & Clean: Standard shipboard supply condition.
- Bright Annealed: For instrumentation and small-bore hydraulic lines.
- Polished OD: Where surface appearance or cleanliness classes are specified.
Dimensional Tolerances
Delivered dimensions are verified against the tolerances below; tighter tolerances can be negotiated for instrumentation and precision applications.
| Dimension | Tolerance |
|---|---|
| OD, tube ≤ 25.4 mm (cold worked) | ± 0.10 mm |
| OD, tube 25.4 – 38.1 mm | ± 0.15 mm |
| OD, tube 38.1 – 50.8 mm | ± 0.20 mm |
| OD, hot-finished pipe ≥ 50.8 mm | ± 1 % of OD |
| Wall thickness | - 12.5 % under-tolerance (min-wall basis) |
| Straightness | ≤ 1 mm per metre |
| Cut length | + 10 / - 0 mm (fixed lengths) |
Common Industrial Applications
Because of its characteristic property profile, Seamless Copper Nickel 90/10 Pipe is specified in the following industries and services:
- Shipbuilding & Marine: Seawater cooling, ballast, sanitary and fire-main piping on naval and commercial vessels — the classic C70600 application.
- Offshore Oil & Gas Platforms: Seawater lift, firewater and process cooling systems resistant to splash-zone corrosion.
- Coastal Power & Desalination Plants: Condenser water boxes, intake piping and brine handling lines.
- Heat Exchangers & Condensers: Tubing where high thermal conductivity plus seawater resistance are both required.
- Aquaculture & Marine Structures: Seawater supply systems benefiting from anti-fouling behavior.
- Cryogenic Equipment: Low-temperature piping where toughness retention matters.
Quality Assurance, Testing and Documentation
Every length of Seamless Copper Nickel 90/10 Pipe passes through a documented quality-control chain before dispatch:
- Material Certification: EN 10204 3.1 mill test certificates are issued for every heat; 3.2 certification with third-party witness (TUV, SGS, BV) is available on request.
- Chemical & Mechanical Testing: Heat-level chemical analysis plus tensile, hardness and, where applicable, flattening, flaring and reverse-flattening tests per the governing standard.
- Non-Destructive Examination: 100 % eddy-current or ultrasonic testing and hydrostatic or pneumatic pressure testing in line with the standard's supplementary requirements.
- Dimensional & Visual Inspection: Full OD, wall thickness, ovality and length verification with visual surface inspection after pickling or finishing.
- Traceability & Marking: Heat numbers stenciled or banded on every length, maintaining complete melt-to-pipe traceability.
Export and Packaging
Pipes are bundled with steel strapping and fitted with plastic or steel end caps, then packed in seaworthy wooden cases or crates and secured in containers for long-distance ocean freight. Standard export documentation — commercial invoice, packing list, certificate of origin, mill test certificates and, where required, third-party inspection reports — accompanies every shipment. Container-load and bulk project orders receive priority production slots and consolidated shipping documentation.
Frequently Asked Questions
Q1. What is the maximum recommended seawater flow velocity for 90/10 pipe?
A: General piping practice limits C70600 to about 3 m/s in continuous flow to protect the corrosion film; short excursions above this are tolerable. Condenser tube design follows specific velocity charts.
Q2. Why is 90/10 usually chosen over 70/30 for ship piping?
A: 90/10 meets the corrosion requirements of most seawater systems at lower cost. 70/30 is reserved for higher-duty service — higher velocities, more aggressive polluted harbors, or higher strength needs.
Q3. Does copper-nickel piping need cathodic protection?
A: C70600 performs well without impressed-current protection and does not require it internally; galvanic compatibility with neighboring alloys should still be reviewed in mixed-material systems.
Q4. Can 90/10 pipe be welded in the field?
A: Yes — shipyards routinely weld it with matching CuNi filler (e.g., AWS ERCuNi) using TIG or MMA processes, with standard joint designs.
Ready to Request a Quotation?
Send us your size range, wall thickness/schedule, standard and quantity for Seamless Copper Nickel 90/10 Pipe, and our engineering team will respond with a detailed technical and commercial offer within 24 hours. Custom sizes, third-party inspection and full export documentation are part of our standard service.
