Copper Nickel 70/30 Explained
Copper Nickel 70/30 (CU-NI 70/30)—also known as Cupronickel 70/30—is a premium copper-nickel alloy composed of 70% copper and 30% nickel, engineered for exceptional performance in highly corrosive marine and industrial environments. This alloy offers superior resistance to seawater corrosion, stress corrosion cracking, biofouling, and erosion, making it one of the most reliable materials for demanding offshore and naval applications. With its high mechanical strength, excellent thermal stability, and outstanding resistance to high-velocity seawater, Copper Nickel 70/30 is widely used in heat exchangers, condensers, seawater intake systems, desalination plants, offshore platforms, and shipbuilding components. Its excellent weldability, durability, and long service life make it a preferred choice for critical cooling and piping systems where consistent performance and reliability are essential.
70/30 CUPRO NICKEL SHEETS AND PLATES EQUIVALENT GRADES
| Common Name | UNS | DIN | Werkstoff Nr. | AFNOR |
|---|---|---|---|---|
| Cupro Nickel 70/30 | C71500 | 2.0882 | NiCr20CuMo | Z2NCUD31-20AZ |
SPECIFICATION OF CUPRO NICKEL 70/30 SHEETS AND PLATES
| Standard | ASTM B151 / ASME SB151 |
|---|---|
| Dimension Standard | JIS, AISI, ASTM, GB, DIN, EN, etc |
| Width | 1000mm, 1219mm, 1500mm, 1800mm, 70 / 300mm, 2500mm, 3000mm, 3500mm, etc |
| Length | 70 / 300mm, 2440mm, 3000mm, 5800mm, 6000mm, etc |
| Thickness | 0.3 mm to 120 mm |
| Form | Coils, Foils, Rolls, Plain Sheet, Shim Sheet, Perforated Sheet, Chequered Plate, Strip, Flats, Blank (Circle), Ring (Flange) etc. |
| Surface Finishing | Hot rolled plate (HR), Cold rolled sheet (CR), 2B, 2D, BA, NO.1, NO.4, NO.8, 8K, mirror, Chequered, embossed, hair line, sand blast, Brush, etching, SATIN (Met with Plastic Coated) etc. |
CHEMICAL COMPOSITION OF CUPRO NICKEL 70/30 SHEETS AND PLATES
| Grade | Cu | Mn | Pb | Ni | Fe | Zn |
|---|---|---|---|---|---|---|
| Cupro Nickel 70/30 | 65 min | 1.0 max | 0.05 max | 29-33 max | 0.4-1.0 max | 1 max |
MECHANICAL PROPERTIES OF CUPRO NICKEL 70/30 SHEETS AND PLATES
| Density | Melting Point | Tensile Strength | Yield Strength (0.2% Offset) | Elongation |
|---|---|---|---|---|
| 0.323 lb/in3 at 68 F | 2260 F | 50000 psi | 70 / 3000 psi | 30 % |
💡 Practical Difference in Use
Use Copper Nickel 90/10 when: excellent seawater corrosion resistance, high ductility, and cost-effective performance are required in moderate marine and heat transfer applications.
→ Example: desalination plants, seawater piping, condensers, heat exchangers, marine hardware, coolers, and shipbuilding components.
Use Copper Nickel 70/30 when: superior strength, higher corrosion resistance, and better performance in high-velocity or aggressive seawater conditions are needed.
→ Example: offshore platforms, naval systems, high-pressure seawater pipelines, power plant heat exchangers, and industrial cooling systems.
Use Copper-Nickel Alternatives (Monel / Admiralty Brass) when: specific mechanical performance, temperature stability, or corrosion resistance requirements exceed Cu-Ni capabilities.
→ Example: chemical processing equipment, acidic media handling, and specialized marine engineering components.
Applications of Copper Nickel 70/30 & 90/10 Sheets and Plates
Copper Nickel alloys are engineered for exceptional resistance against seawater corrosion, erosion, and biofouling, making them ideal for marine and industrial environments. Both grades offer long service life, stable mechanical strength, and excellent weldability for critical fluid handling and cooling systems.
- Marine Applications: Seawater piping, ship hulls, desalination systems, marine heat exchangers.
- Industrial Systems: Condenser tubing, power plant cooling, brine heaters, offshore structures.
- Instrumentation & Engineering: Pumps, valves, pressure vessels, fittings, and fluid handling components.
When to Choose Copper Nickel 70/30 vs. 90/10?
Your choice depends on seawater velocity, corrosion resistance needs, mechanical strength, system pressure, and fabrication preferences.
Choose Copper Nickel 90/10 when:
- General marine corrosion resistance is required
- Cost-effective solution is preferred
- Material will be used in moderate seawater flow
- High ductility and easy fabrication are important
- Applications include desalination units, seawater piping & heat exchangers
Choose Copper Nickel 70/30 when:
- Higher strength and toughness are required
- System faces high seawater velocity or turbulence
- Excellent resistance to erosion and cavitation is needed
- Used in offshore, naval, and high-pressure marine systems
- Ideal for industrial cooling, process equipment & defense marine systems
Choose Monel / Admiralty Brass when:
- Very high corrosion resistance in aggressive media is required
- Material must perform against acids and chemical attack
- Used in chemical plants or advanced marine engineering
- Applications include pumps, valves, and harsh chemical environments
- Suited for specialized high-temperature or high-corrosion areas
Industries That Use Copper Nickel 70/30 & 90/10
Copper Nickel alloys are widely used in industries where long-term seawater corrosion resistance, mechanical stability, and biofouling protection are essential.
Preferred material for seawater handling systems and structural marine applications.
Uses
Seawater pipes, ship hull plating, ballast systems, condensers.
Why Copper Nickel?
Outstanding resistance to marine corrosion and biological growth.
Commonly used in thermal and desalination plants handling brackish or seawater.
Uses
Heat exchangers, brine heaters, condensers, cooling systems.
Why Copper Nickel?
Stable performance under continuous seawater flow and thermal cycling.
Widely used in high-pressure and turbulent seawater conditions.
Uses
Offshore platforms, naval cooling systems, subsea piping.
Why Copper Nickel?
High strength, excellent erosion resistance, and proven reliability.
Reliable for corrosive fluid handling and thermal equipment.
Uses
Pumps, valves, evaporators, process piping.
Why Copper Nickel?
Resistant to brine, chlorides, and mildly acidic environments.
Used where thermal conductivity and corrosion resistance are crucial.
Uses
Cooling coils, condenser units, evaporator systems.
Why Copper Nickel?
Excellent heat transfer efficiency and long service life.
Essential in systems handling saline, brackish, or treated water.
Uses
Filtration units, pumps, valves, flow control equipment.
Material Selection
90/10 for general systems, 70/30 for high-pressure/velocity systems.
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