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Copper Nickel Alloy 70/30 (Cu-Ni) | Product Overview
Introduction To Copper Alloys CU-NI 70/30 / UNS C71500 / CW354H
MOKSH TUBES & FITTINGS LLP is a leading manufacturer, supplier, exporter, importer, and stockist of Copper Nickel 70/30 (UNS C71500 / CW354H) products. We offer a complete range including Seamless & Welded Pipes and Tubes, Sheets & Plates, Rods, Bars, Pipe Fittings, Flanges, Wires, Fasteners, and Custom Machined Components.
Copper Alloys CU-NI 70/30, is a stronger and more corrosion-resistant copper-nickel alloy than 90/10. It is well suited for highly corrosive environments, including high-velocity seawater and industrial chemical exposure. With enhanced mechanical strength, excellent weldability, and strong resistance to biofouling, erosion, and hydrogen embrittlement, CU-NI 70/30 is widely used in demanding marine, offshore, and thermal applications.
Chemical Composition
| Element | Composition (%) |
|---|---|
| Copper | Balance |
| Nickel | 29.0 – 33.0 |
| Iron | 0.4 – 1.0 |
| Manganese | 1.0 max |
| Zinc | 1.0 max |
| Lead | 0.05 max |
| Others | ≤ 0.50 (Total) |
Technical Composition
Physical Properties
| Property | Metric | Imperial |
|---|---|---|
| Density | 8.94 g/cm³ | 0.323 lb/in³ |
| Melting Point | 1240 – 1310 °C | 2260 – 2390 °F |
| Thermal Conductivity | 33 W/m·K | 19 Btu/ft·hr·°F |
| Electrical Resistivity | 0.520 µΩ·m | 312 ohm·cmil/ft |
| Specific Heat Capacity | 0.38 J/g·K | 0.09 Btu/lb·° |
| Coefficient of Expansion | 9.8 x 10⁻⁶ /°F | 17.6 x 10⁻⁶ /°C |
Mechanical Properties
| Property | Annealed / Type O | Cold-Drawn (Stress-Relieved) | Hot-Rolled / Sheet |
|---|---|---|---|
| Tensile Strength (ksi / MPa) | 360 MPa (52 ksi) min | 495 MPa (72 ksi) | 372–517 MPa (54–75 ksi) |
| Yield Strength (0.2%) (ksi / MPa) | 125 MPa (18 ksi) min | 345 MPa (50 ksi) | 125–300 MPa (18–43 ksi) |
| Elongation (%) | ≥ 30 % | 12–15 % | 30–45 % |
| Brinell Hardness (HB) | – | – | 80–120 HB |
| Rockwell Hardness (B) | – | ≤ 88 B (H08 spring) | 81 B |
Products in Copper Alloys CU-NI 70/30
Copper Alloys CU-NI 70/30 is available in:
Copper Alloys CU-NI 70/30 products are produced to the following global standards:
Uses and Advantages
Highly resistant to pitting, crevice corrosion, and biofouling in both stagnant and flowing seawater.
Stronger than CU-NI 90/10, suited for demanding structural and pressure-bearing applications.
Performs reliably in thermal cycling and exposure to acids, salts, and ammonia.
Suitable for all standard welding methods with minimal pre/post-heat requirements.
Ideal for installations in remote or offshore environments with limited access.
Applications of Copper Alloys CU-NI 70/30
Copper Alloys CU-NI 70/30 is widely used in highly corrosive and high-stress applications in marine and industrial sectors:
Marine & Shipbuilding
Seawater piping systems, propeller sleeves, condenser plates, seawater valves
Heat Exchangers & Condensers
Used in desalination plants, chemical processing, and brine systems
Offshore Oil & Gas
Firewater systems, risers, deck piping, platform infrastructure
Power Plants & Thermal Stations
Feedwater heaters, condenser tubes, cooling water lines
Defense & Naval Applications
Military-grade piping, hull-mounted components, submarine systems
Water Treatment & Desalination
Brine heaters, evaporator shells, and saltwater discharge systems
WHY CHOOSE US?
FAQ's
What is Copper Nickel 70/30 and how is it different from 90/10?
Copper Nickel 70/30, also known as UNS C71500 or CW354H, is a copper alloy containing about 70% copper and 30% nickel with small additions of iron and manganese. Compared to Copper Nickel 90/10, the 70/30 grade offers greater mechanical strength, improved corrosion resistance, and excellent durability in highly aggressive environments such as fast-flowing seawater and chemical processing systems.
What are the main benefits of using Copper Nickel 70/30 alloy?
The key benefits of Copper Nickel 70/30 include outstanding resistance to pitting, crevice corrosion, biofouling, and stress cracking in both stagnant and turbulent seawater. It is stronger than CU-NI 90/10, performs reliably under thermal cycling, and is resistant to acidic and saline environments. Additionally, it has excellent weldability with minimal pre or post-heat treatment requirements, making it a reliable choice for marine and offshore installations.
Where is Copper Nickel 70/30 commonly used?
Copper Nickel 70/30 is widely used in marine and shipbuilding industries for seawater piping, condenser plates, valves, and propeller sleeves. It is a preferred material in power plants for feedwater heaters, condensers, and cooling water lines, in desalination plants for brine heaters and evaporator shells, and in offshore oil and gas for firewater systems, risers, and deck piping. Defense and naval sectors also use it extensively for submarine systems and hull-mounted components due to its long term performance in harsh environments.
What Copper Nickel 70/30 products are supplied by MOKSH TUBES & FITTINGS LLP?
MOKSH TUBES & FITTINGS LLP offers a comprehensive range of Copper Nickel 70/30 products including seamless and welded pipes and tubes, sheets, plates, coils, strips, round bars, flats, hex bars, pipe fittings, flanges, fasteners, wires, and custom machined components. All materials are produced in compliance with international standards and can be customized in terms of size, thickness, and finish to meet specific project requirements.
Why choose MOKSH TUBES & FITTINGS LLP for Copper Nickel 70/30 materials?
MOKSH TUBES & FITTINGS LLP is a trusted manufacturer, supplier, and exporter of Copper Nickel 70/30 with extensive industry experience. The company provides marine-grade certified products from reputed mills, an extensive stock range, cut-to-size services, and global logistics support. With expertise in serving shipyards, EPC contractors, power plants, refineries, and defense projects, the company ensures high-quality CU-NI 70/30 products with full traceability and reliable performance.
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