C71500 CuNi 70/30 Copper Nickel Tube for Marine Water Piping with High Tensile Strength and Anti-Corrosion Properties
C71500 CuNi 70/30 Cupronickel Seamless Tube Marine Water Piping Anti-Corrosion Pipe
1.Product Description
Copper nickel tube (also known as cupronickel tube) is a copper-based alloy tubing with nickel as the primary alloying element, typically containing 5% to 30% nickel. The most commercially common grades are 90-10 (10% nickel) and 70-30 (30% nickel) copper-nickel alloys, with small but important additions of iron and manganese to optimize corrosion resistance. These alloys exhibit a uniform face-centered cubic (FCC) structure that provides high toughness and excellent resistance to seawater corrosion. The tubes are available in both seamless and welded forms, complying with standards such as ASTM B466 (seamless) and ASTM B467 (welded). Copper-nickel tubes feature a silver-white metallic luster, with higher nickel content resulting in a whiter appearance.
2.Product Applications
Copper nickel tubes are widely used in marine and industrial environments where corrosion resistance is critical. The main applications for 90-10 and 70-30 copper-nickel alloys include:
-
Seawater piping systems – cooling water, firewater, and ballast systems on ships and offshore platforms
-
Heat exchangers and condensers – in power generation, chemical processing, and marine engineering
-
Desalination plants – multi-stage flash (MSF) and multiple effect distillation (MED) systems
-
Offshore oil and gas platforms – seawater cooling and firewater/deluge systems
-
Shipbuilding – hulls, platform riser and leg sheathing, oil coolers
-
Hydraulic tubing – including brake tubing for vehicles
-
Chemical processing and power generation – heat transfer equipment and corrosion-resistant piping
3.Product Advantages
Excellent corrosion resistance – Copper-nickel alloys exhibit exceptional resistance to seawater corrosion, with general corrosion rates ranging between 0.025 and 0.0025 mm/year. The alloys form stable, adherent protective films composed of copper oxides and nickel-enriched compounds that continue to grow and self-heal during seawater exposure.
Superior biofouling resistance – The alloy resists marine organism attachment and biofouling, making it ideal for long-term seawater exposure.
High strength and durability – Both alloys have good mechanical strength and ductility, with 70-30 alloy possessing greater inherent strength. Strength can be further increased by work hardening.
Excellent thermal conductivity – 90-10 alloy has a thermal conductivity of approximately 50 W·m⁻¹·K⁻¹, while 70-30 alloy offers about 29 W·m⁻¹·K⁻¹, ensuring efficient heat exchange.
Good weldability and formability – The tubes can be welded, bent, flared, and processed through plastic deformation.
Long service life – Seawater piping systems using copper-nickel tubes have extended service lives, directly impacting vessel availability and lifecycle costs.
4.Key Product Specifications
| Parameter Item | 90-10 (C70600) | 70-30 (C71500) | General Notes / Remarks |
| Chemical Composition | |||
| Copper (Cu) content | ≥99.5% (including Ni) | ≥65% (including Ni) | Ni counted in Cu |
| Nickel (Ni) content | 9.0 – 11.0% | 29.0 – 33.0% | — |
| Iron (Fe) content | 1.0 – 1.8% | 0.4 – 1.0% | — |
| Lead (Pb) content | ≤0.05% (standard) | ≤0.05% (standard) | — |
| Mechanical Properties (Annealed) | |||
| Tensile Strength | 275 – 310 MPa | 345 – 310 MPa | 70-30 has higher strength |
| Yield Strength | 105 – 90 MPa | 140 – 105 MPa | — |
| Elongation | ≥25% | ≥30% | — |
| Physical Properties | |||
| Density | 8.90 g/cm³ | 8.94 g/cm³ | — |
| Thermal Conductivity | ≈50 W·m⁻¹·K⁻¹ | ≈29 W·m⁻¹·K⁻¹ | — |
| Melting Point | 1100 – 1150 °C | ≈1171 °C | — |
| Electrical Resistivity | 19 µΩ·cm | 37.4 µΩ·cm | — |
| Coefficient of Thermal Expansion (20-300°C) | 17 ×10⁻⁶ K⁻¹ | 16.2 ×10⁻⁶ K⁻¹ | — |
| Dimensional Range (General) | |||
| Outside Diameter | Φ6 – 325 mm | Same | Custom sizes available |
| Wall Thickness | 1 – 30 mm | Same | — |
| Single Piece Length | Up to 16 meters | Same | — |
| Applicable Standards (General) | ASTM B466 (seamless), ASTM B467 (welded), ASTM B111 (heat exchangers), DIN 86019, GB/T (B10, B30) | Same |
FAQ
1. Are you trading company or manufacturer ? We are manufacturer ,You can see the certification.
2.How long is your delivery time? Generally it is 5-10 days if the goods are in stock. or it is 15-20 days if the goods are not in stock, it is according to quantity.
3. Do you provide samples ? is it free or extra ? Yes, we could offer the sample for free charge but need pay the cost of freight.
4. What is your terms of payment ? Payment<=1000USD, 100% in advance. Payment>=1000USD, 50% T/T in advance ,balance before shippment.
Get in Touch
Have questions about our products or want to discuss a custom order? Our team is ready to help you.