Copper nickel alloys are alloys of copper (base metal with the largest individual content) and nickel with or without other elements, whereby the zinc content may not exceed 1%. When other elements are present, nickel has the largest individual content after copper. These alloys offer excellent resistance to seawater, brine water, organic compounds, salts, and diluted non-oxidizing acids.
Additions of iron significantly improve the resistance of copper nickel alloys to erosion corrosion in flowing seawater and other aggressive waters.
Available Product Forms
| Product Form | C70600 (90/10) | C71500 (70/30) |
|---|---|---|
| Plate / Sheet | ✓ | ✓ |
| Seamless Tube | ✓ | ✓ |
| Welded Tube | ✓ | ✓ |
| Seamless Pipe | ✓ | ✓ |
| Welded Pipe | ✓ | ✓ |
| Round Bar | ✓ | ✓ |
| Flanges | ✓ | ✓ |
| Seamless & Welded BW Fittings | ✓ | ✓ |
Specifications & Standards by Alloy
UNS C70600 / C70620 (CuNi 90/10)
| Standard | Specification |
|---|---|
| ASME | SB111, SB171, SB359, SB395, SB466, SB467, SB543 |
| ASTM | B111, B122, B151, B171, B359, B395, B432, B466, B467, B543, B608 |
| DIN | 2.0872 |
| MIL | C-15726, T-15005, T-16420, T-22214 |
| SAE | J461, J463 |
UNS C7060X (EEMUA Specification)
| Standard | Specification |
|---|---|
| EEMUA | 144 90/10, 145 90/10, 14 90/1 |
UNS C71500 / C71520 (CuNi 70/30)
| Standard | Specification |
|---|---|
| ASME | SB111, SB171, SB359, SB395, SB466, SB467, SB543 |
| ASTM | B111, B122, B151, B171, B359, B395, B432, B467, B543, B552, B608, F467, F468 |
| DIN | 2.0882 |
| MIL | C-15726, T-15005, T-16420, T-22214 |
| SAE | J461, J463 |
UNS C71640
| Standard | Specification |
|---|---|
| ASTM | B111, B543, B552 |
Chemical Composition
| Element | C70600 / C70620 (90/10) | C7060X (EEMUA) | C71500 (70/30) | C71640 |
|---|---|---|---|---|
| Copper (Cu) | 88.6% min. | Rem. | 65.0% min. | Rem. |
| Nickel (Ni) | 9.0 - 11.0% | 10.0 - 11.0% | 29.0 - 33.0% | 29.0 - 32.0% |
| Iron (Fe) | 1.8% max. | 1.5 - 2.0% | 0.4 - 1.0% | 1.7 - 2.3% |
| Manganese (Mn) | 1.0% max. | 0.5 - 1.0% | 1.0% max. | 1.5 - 2.5% |
| Lead (Pb) | 0.05% max.* | 0.01% max. | 0.05% max.* | 0.05% max.* |
| Zinc (Zn) | 1.0% max.* | 0.2% max. | 1.0% max.* | 1.0% max.* |
| Phosphorus (P) | - | 0.2% max. | - | - |
| Sulfur (S) | - | 0.2% max. | - | - |
Mechanical Properties (Minimum Values)
| Alloy | Tensile Strength (KSI) | Yield Strength (KSI) | Elongation (%) |
|---|---|---|---|
| C70600 / C70620 (90/10) | 38 | 15 | 30 |
| C7060X (EEMUA 90/10) | 40 | 15 | 30 |
| C71500 (70/30) | 52 | 18 | 45 |
| C71640 | 63 | 25 | - |
Key Applications
| Industry | Application |
|---|---|
| Desalination | Tubing, piping, and heat exchanger components |
| Marine / Shipbuilding | Seawater piping systems, condensers, and cooling systems |
| Offshore Oil & Gas | Fire water systems, risers, platform leg sheathing |
| Power Generation | Condenser tubes, heat exchangers |
| Chemical Processing | Corrosive fluid handling |
Corrosion Resistance
| Alloy | Corrosion Resistance Characteristics |
|---|---|
| C70600 / C7060X (90/10) | Excellent resistance to seawater and brackish water. The addition of iron and manganese provides outstanding performance in marine environments. |
| C71500 (70/30) | Of all commercial copper alloys, C71500 offers the best resistance to aqueous corrosion. It is resistant to acid solutions and highly resistant to stress corrosion cracking and impingement corrosion. Additionally, C71500 offers greater strength for higher pressure applications. |
Heat Resistance
| Alloy | Maximum Service Temperature |
|---|---|
| C70600 (CuNi10Fe1Mn) | Up to 300°C in pressure vessel construction |
| C71500 (CuNi30Mn1Fe) | Up to 350°C in pressure vessel construction |
Heat Treatment Guidelines
| Treatment Type | Temperature Range | Notes |
|---|---|---|
| Recrystallisation Annealing | 620 – 900°C | High temperatures = short annealing times (continuous annealing); Low temperatures = long annealing times (static annealing) |
| Stress-Relief Annealing | 280 – 500°C | For removing residual stresses after cold working |
| Atmosphere Recommendation | Excluding air or slightly reducing atmosphere | Avoids pickling that is required with air-containing annealing atmospheres |
Product Specifications
For C70600 Copper Nickel (90/10)
| Standard Type | Specific Standards |
|---|---|
| ASME | SB111, SB171, SB359, SB395, SB466, SB467, SB543 |
| ASTM | B111, B122, B151, B171, B359, B395, B432, B466, B467, B543, B608 |
For C71500 Copper Nickel (70/30)
| Standard Type | Specific Standards |
|---|---|
| ASME | SB111, SB171, SB359, SB395, SB466, SB467, SB543 |
| ASTM | B111, B122, B151, B171, B359, B395, B432, B467, B543, B552, B608, F467, F468 |
Detection
| Inspection Method | Standard / Purpose |
|---|---|
| Eddy Current Testing | ASTM E243 - Detects defects in non-ferromagnetic tubing |
| Hydrostatic Test | Pressure integrity verification |
| Ultrasonic Testing | Wall thickness measurement |
| Chemical Analysis | Spectrometer - Verifies c71500 chemical composition or C70600 composition |
| Mechanical Testing | Tensile, hardness, flattening, expansion tests |
| Flattening Test | Required per ASTM B111 |
| Expansion Test | 30% at 60° (after annealing) |
Packaging
| Item | Method |
|---|---|
| Small diameter tubes (≤ 12 inch) | Waterproof paper + plastic bag + wooden case |
| Large diameter pipes (> 12 inch) | Plastic end caps + steel strip bundles + wooden pallets |
| Flanges and fittings | Anti-rust oil + plastic film + carton + wooden case |
| Marking | Grade (C70600/C71500/C71640), size, schedule, heat number, standard (ASTM B111 / ASME SB466) |
Factory Equipment
| Equipment | Purpose for Copper Nickel Production |
|---|---|
| Induction Melting Furnace | Precise control of c71500 chemical composition and C70600 composition |
| Continuous Casting Machine | Billet production |
| Extrusion Press | Hollow shell formation |
| Cold Pilger Mill | Tube diameter reduction |
| Draw Bench | Final sizing and surface finish |
| Annealing Furnace | Stress relief and recrystallisation (620-900°C) |
| Straightening Machine | Dimensional accuracy |
| NDT Equipment | Eddy current and ultrasonic testing |
Certificates
