UNS C71500 Copper Nickel, also known as 70/30 Copper-Nickel, C71500 CuNi30Fe1Mn, or CW354H, is a high-strength copper-nickel alloy containing approximately 70% copper and 30% nickel, with controlled additions of iron and manganese to enhance mechanical strength and seawater corrosion resistance.
It offers superior resistance to stress-corrosion cracking, erosion, and biofouling, even in turbulent or polluted seawater, making it ideal for heat exchangers, condensers, marine piping, and offshore oil & gas systems.
Manufactured in accordance with ASTM B111, ASTM B466, ASTM B122, ASTM B171, and EN 12451, C71500 Copper Nickel Alloy is supplied in tubes, plates, rods, fittings, and coils, with ISO 9001 / ASTM-compliant quality certifications for global export.
Product Forms
| Form | Description |
|---|---|
| Pipe | Seamless, welded |
| Tube | Seamless condenser tube |
| Sheet / Plate | Hot rolled, cold rolled |
| Rod / Bar | Round, hex, square |
| Fittings | Elbow, tee, reducer |
| Flanges | Slip-on, weld neck, blind |
| Coil / Strip | Flexible tube forming |
International Standards
| Standard System | Grade / Specification |
|---|---|
| UNS | C71500 |
| ASTM | B111 (Tube), B122 (Plate/Sheet), B466 (Pipe), B467 (Seamless Pipe & Tube) |
| ASME | SB111, SB122, SB466, SB467 |
| EN (Europe) | CuNi30Mn1Fe (EN 1652 / EN 12451) |
| DIN (Germany) | 2.0882 |
| ISO | CuNi30Fe1Mn |
| JIS (Japan) | C7150 |
Chemical Composition (Typical %)
| Element | Content (%) |
|---|---|
| Copper (Cu) | 66.0 – 70.0 |
| Nickel (Ni) | 29.0 – 33.0 |
| Iron (Fe) | 0.4 – 1.0 |
| Manganese (Mn) | 0.5 – 1.0 |
| Lead (Pb) | ≤0.02 |
| Zinc (Zn) | ≤0.50 |
Mechanical Properties (Typical)
| Property | Annealed | Cold Worked (H55) |
|---|---|---|
| Tensile Strength (MPa) | 380 – 480 | 480 – 550 |
| Yield Strength (MPa) | 130 – 180 | 170 – 220 |
| Elongation (%) | ≥30 | ≥15 |
| Hardness (HV) | 90 – 120 | 120 – 150 |
| Density | 8.95 g/cm³ | - |
| Thermal Conductivity | 29 W/m·K | - |
| Electrical Conductivity | ~4% IACS | - |
| Max Working Temp | 350°C (662°F) | - |
C71500 vs C70600 – Comparison
| Property | C71500 (70/30 CuNi) | C70600 (90/10 CuNi) |
|---|---|---|
| Nickel Content | ~30% | ~10% |
| Strength | Higher | Lower |
| Corrosion Resistance | Excellent (aggressive seawater) | Very good (milder seawater) |
| Biofouling Resistance | Superior | Good |
| Cost | Higher | More economical |
| Fabrication | Good | Excellent (easier to form) |
| Max seawater velocity | Up to 4.5 m/s | Up to 3.5 m/s |
Why Choose 70/30 CuNi Over 90/10?
Superior corrosion resistance in harsh seawater: Enhanced resistance to high-velocity seawater, polluted or oxygenated seawater, and chloride-induced corrosion. Ideal for offshore installations.
Higher strength & erosion resistance: Higher tensile strength, better resistance to erosion-corrosion, longer service life under high flow conditions. Best for heavy-duty piping systems.
Better anti-biofouling performance: Naturally resists marine organism growth and biofouling buildup in pipes and tubes. Reduces maintenance cost in marine piping systems.
Preferred for offshore & power plant applications: Used extensively in offshore oil & gas platforms, desalination plants, and power plant condensers.
Product Forms & Standard Sizes
1. Seamless Tube / Pipe (ASTM B111 / B466 / EN 12451)
| OD (inch) | OD (mm) | Wall Thickness (mm) | Length | Temper | Application |
|---|---|---|---|---|---|
| 1/4" | 6.35 | 0.7 | 3 – 6 m | Annealed (O60) | Condenser tubing |
| 3/8" | 9.52 | 0.9 | 3 – 6 m | Light drawn | Seawater coolers |
| 1/2" | 12.7 | 1.0 | 3 – 6 m | O61 | Heat exchangers |
| 3/4" | 19.05 | 1.5 | 3 – 6 m | Cold worked | Power plant pipelines |
| 1" – 4" | 25.4 – 101.6 | 1.5 – 6.0 | 3 – 6 m | Annealed / H55 | Marine systems |
| Up to 12" | 300 | 1.5 – 8.0 | 6 m custom | Annealed | Offshore oil cooling |
2. Plate & Sheet (ASTM B122 / B171)
| Thickness (mm) | Width (mm) | Length (mm) | Finish | Application |
|---|---|---|---|---|
| 1.0 – 3.0 | 600 – 1200 | 2000 – 3000 | Mill Finish | Condenser plates |
| 4.0 – 25.0 | 600 – 1500 | 2000 – 6000 | Hot Rolled | Tube sheet & structural plates |
| 30.0 – 50.0 | 600 – 1200 | Custom | Machined | Pressure-resistant base plates |
3. Rod & Bar (ASTM B151)
| Diameter (mm) | Length | Temper | Application |
|---|---|---|---|
| 6 – 150 | 3 m | H55 / M30 | Valves, flanges, connectors |
4. Coil / Strip (ASTM B122)
| Thickness (mm) | Width (mm) | Coil Weight | Finish | Application |
|---|---|---|---|---|
| 0.3 – 2.0 | 10 – 400 | 50 – 250 kg | Bright / Smooth | Flexible tube forming, shielding |
5. Fittings & Flanges (ASTM B466 / B467)
| Type | Size Range | Standard | Application |
|---|---|---|---|
| Elbow / Tee / Reducer | 1/2" – 12" | ASTM B466 / B467 | Seawater pipelines |
| Flange (Slip-on / Weld Neck) | 1/2" – 24" | ASTM B151 | Shipbuilding & desalination systems |
Applications
Seawater Piping Systems: Marine piping networks for ships, offshore platforms, and coastal facilities
Heat Exchangers & Condensers: Power plants and desalination systems (continuous seawater exposure)
Shipbuilding & Marine Engineering: Cooling water systems, firewater systems, ballast water systems
Offshore Oil & Gas Platforms: Seawater lift lines, injection systems, platform cooling circuits
Desalination Plants: Intake and discharge pipelines, evaporator and condenser tubing
Power Plant Feedwater Heaters
Key Features & Advantages
Excellent corrosion resistance in seawater and brackish environments
High mechanical strength and resistance to erosion & stress cracking
Outstanding fabrication, welding, and forming properties
Low biofouling tendency; ideal for long-term marine exposure
Excellent thermal conductivity for heat transfer equipment
Compatible with C70600 (90/10 Cu-Ni) and titanium in multi-metal systems
Certified to ASTM / EN / ISO standards for global export
Quality Certifications & Testing
Available certificates:
Mill Test Certificate (EN 10204 3.1 / 3.2)
Eddy Current Testing
Hydrostatic Testing
PMI Testing
Dimensional and Mechanical Inspection Reports
ASTM B111, B466, B122, B171 Compliance
Testing methods:
Chemical verification by spectro analysis
Mechanical testing (tensile, yield, elongation, hardness)
Hydrostatic testing for pipes and tubes
Eddy current testing for seamless tubes
Dimensional inspection per ASTM standards
FAQ
Q1: What's the main difference between C71500 (70/30 Cu-Ni) and C70600 (90/10 Cu-Ni)?
C71500 has higher nickel content (30%), offering greater strength, corrosion, and erosion resistance, especially suitable for polluted seawater or high-pressure systems. C70600 contains 10% nickel and is more economical for low-velocity clean seawater.
Q2: Is C71500 resistant to biofouling?
Yes. Its copper content prevents marine organism growth, while the nickel enhances oxide film stability, minimizing fouling and reducing maintenance requirements in marine piping systems.
Q3: Can C71500 be welded easily?
Yes. It can be welded using TIG, MIG, or brazing with matching filler metals (AWS A5.7 Class ERCuNi or CuNi30). Cleaning and argon shielding are essential for quality welds.
Q4: What is the maximum seawater flow velocity for C71500 tubes?
Up to 4.5 m/s in clean seawater. This is higher than C70600's 3.5 m/s limit, due to its improved impingement resistance from higher nickel and iron content.
Q5: Does C71500 require special maintenance in marine service?
Only minimal cleaning is needed. The self-protective oxide layer ensures long-term stability without continuous treatment, reducing lifecycle costs in seawater systems.
Q6: What certificates and testing are available?
Mill Test Certificate (EN 10204 3.1 / 3.2), Eddy Current Testing, Hydrostatic Testing, PMI Testing, Dimensional and Mechanical Inspection Reports, ASTM B111, B466, B122, B171 Compliance.
Q7: Is C71500 suitable for high-pressure or offshore systems?
Yes. Its high strength and seawater resistance make it ideal for offshore oil & gas platforms, power stations, and heat recovery systems operating under high pressure and flow velocities.
Q8: Can C71500 be used with titanium or stainless steel?
Yes, provided dielectric insulation is used to prevent galvanic corrosion between dissimilar metals in seawater systems.
Q9: What is the maximum working temperature for C71500?
Maximum working temperature is 350°C (662°F). Thermal conductivity is 29 W/m·K with density of 8.95 g/cm³.
Q10: What forms of C71500 are available?
Pipe, tube (seamless), sheet, plate, rod, bar, fitting, flange, and coil/strip. All manufactured to ASTM B111, B466, B122, B171, and EN 12451 standards.
Packaging Details
Length: 3 m / 6 m standard, or custom cut
Surface Finish: Mill, polished, or annealed
Marking: Grade + size + heat number + ASTM standard
Packaging: Plastic-capped bundles or seaworthy wooden crates
Certifications: ASTM / EN / ISO 9001 with MTC 3.1
Production Equipment for C71500 Copper Nickel Products
| Equipment | Specification | Purpose |
|---|---|---|
| Induction Melting Furnaces | 6 ton capacity, argon stirring | Precise control of chemical composition: Ni 29-33%, Fe 0.4-1.0%, Mn 0.5-1.0% |
| Horizontal Continuous Caster | 200 mm billet diameter | Produces solid billet for pipe, tube, and bar extrusion |
| Extrusion Press | 3500 ton capacity | Pierces billet to form hollow pipe and tube shells |
| Hot Rolling Mill | Reversing type | Reduces plate and sheet thickness |
| Cold Pilger Mills | Multiple stands, up to 40 m length | Reduces OD and wall thickness of tubes and pipes |
| Draw Benches | 30 ton and 60 ton capacities | Final sizing of pipes, tubes, and bars; achieves straightness of 0.5 mm/m |
| Annealing Furnaces | 600-815°C (1112-1500°F), water quench | Produces annealed temper (O60/O61); restores ductility and corrosion resistance |
| ERW/EFW Pipe Mill | High-frequency welding | Produces welded pipes and tubes |
| U-Bend Bender | CNC controlled | Forms U-bend tubes for heat exchangers |
| Forging Press | Multiple capacities | Produces forged fittings and flanges |
| CNC Machining Center | Multi-axis | Precision machining of flanges, fittings, and custom components |
| Tube Straightening Machine | 6-roll rotary | Corrects bending; achieves straightness of 0.5 mm/m |
| Eddy Current Tester | 100% online, rotating probe | Detects pinholes, slivers, and wall variations in seamless tubes |
| Ultrasonic Tester | Multi-channel | Laminar flaw detection for high-specification orders |
| Hydrostatic Tester | Pressure up to 6000 psi | Leak tests each pipe and tube; automated pressure recording |
| Metallurgical Laboratory | OES spectrometer, universal tensile tester, hardness tester, microscopes | In-process and final quality verification; PMI testing |
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