The preferred material for seawater piping systems worldwide. Copper nickel alloys offer outstanding biofouling resistance, excellent corrosion resistance in marine environments, and long service life in offshore, naval, and desalination applications.
Copper nickel alloys have been used in naval and marine applications for over a century. Their natural biofouling resistance eliminates the need for antifouling coatings, making them ideal for seawater cooling systems, fire suppression, and desalination plants.
90% copper, 10% nickel — the workhorse of marine piping. Excellent resistance to seawater corrosion and biofouling. Cost-effective choice for seawater cooling systems, shipbuilding, offshore platforms, and coastal power plants. Good resistance to impingement attack at moderate flow velocities.
70% copper, 30% nickel — higher performance for more demanding marine and desalination environments. Superior corrosion resistance, higher strength, and better resistance to impingement at higher flow velocities. Specified for desalination plants, naval vessels, and high-velocity seawater systems.
| Parameter | CuNi 90/10 (C70600) | CuNi 70/30 (C71500) |
|---|---|---|
| Nickel Content | 9–11% | 29–33% |
| Corrosion Resistance | Good — seawater service | Better — aggressive marine |
| Max Flow Velocity (seawater) | ~3 m/s | ~4.5 m/s |
| Strength | Standard | Higher yield & tensile |
| Biofouling Resistance | Excellent | Excellent |
| Cost | Lower | Higher (more nickel) |
| Typical Application | Seawater cooling, offshore, ships | Desalination, naval, high-velocity |
| Specify When | Standard seawater service | High velocity or demanding marine |
Rule of thumb: 90/10 for most standard seawater applications. 70/30 when flow velocities exceed 3 m/s, for desalination plants, or when superior corrosion resistance is needed.
| Grade | ASTM | UNS | Cu % | Ni % | Fe % | Mn % | Min Tensile |
|---|---|---|---|---|---|---|---|
| CuNi 90/10 | B466 / B467 | C70600 | Bal. | 9–11 | 1.0–1.8 | 1.0 max | 275 MPa |
| CuNi 70/30 | B466 / B467 | C71500 | Bal. | 29–33 | 0.4–1.0 | 1.0 max | 345 MPa |
| Parameter | Range | Notes |
|---|---|---|
| Pipe Size (NPS) | ½" to 12" NB | Larger sizes on request |
| Wall Schedule | Sch 10, 40, 80 | Per ASME B16.9 |
| Fitting Standard | ASME B16.9 | MSS SP-43 also available |
| Material Certificate | EN 10204 3.1 MTC | Chemical + mechanical |
| Surface | Mill finish (standard) | Bright annealed on request |
We have supplied CuNi fittings to shipbuilding yards, offshore platform contractors, and desalination plant EPC companies across Asia, Middle East, and Europe.
90/10 and 70/30 maintained in common sizes year-round. Urgent dispatch possible for standard requirements — critical for vessel maintenance and repair.