Copper Nickel (Cu-Ni) Alloys are copper-based alloys containing nickel as the primary alloying element, with minor additions of iron and manganese. These alloys are engineered for excellent corrosion resistance, particularly in seawater and brackish water environments. The two most common grades, C70600 (Cu-Ni 90/10) and C71500 (Cu-Ni 70/30), offer distinct advantages for various service conditions.
Inherent advantages include:
Exceptional Seawater Corrosion Resistance: Outstanding resistance to general corrosion, pitting, and crevice corrosion in seawater and other saline solutions.
Erosion & Impingement Resistance: Superior resistance to erosion-corrosion, especially in high-velocity flows, crucial for piping and heat exchanger tubes.
Anti-Fouling Properties: C70600 (90/10 Cu-Ni) demonstrates good resistance to biofouling (growth of marine organisms), reducing maintenance needs.
High Strength & Ductility: Good mechanical strength and ductility, allowing for ease of fabrication while maintaining structural integrity.
Key Features & Benefits
Superior Seawater Corrosion Resistance
Excellent Erosion & Impingement Resistance
Natural Biofouling Resistance (especially C70600)
Good Strength & Ductility
Thermal Stability
Ease of Fabrication & Joining
Full Material Traceability & Certifications (EN 10204 3.1 MTCs)
Longevity & Reduced Maintenance
Product Forms Available
Pipes & Tubes: Seamless and welded for heat exchangers, condensers, piping systems, and desalination plants.
Pipe Fittings: Butt-weld fittings (elbows, tees, reducers, caps), threaded fittings, and socket weld fittings.
Flanges: Weld Neck, Slip-On, Blind, Socket Weld, Threaded, Lap Joint, and Orifice flanges.
Bars & Rods: Round, square, flat, and hexagonal bars for shafts, fasteners, and general machining.
Sheets & Plates: Hot rolled and cold rolled for tank fabrication, structural components, and heat exchanger plates.
General Dimensions & Technical Capabilities
| Product Type | Size Range |
|---|---|
| Pipes & Tubes | NPS 1/8 to NPS 48, various schedules and wall thicknesses |
| Fittings | NPS 1/2 to NPS 48, Class 150 to Class 2500 (flanges), Class 3000 to 9000 (forged fittings) |
| Flanges | NPS 1/2 to NPS 60, Pressure Classes 150 to 2500, RF / RTJ facing |
| Bars | Diameter 6 mm to 300 mm, custom lengths |
| Sheets & Plates | Thickness 1 mm to 100 mm, custom sizes |
Manufacturing processes: Hot rolling, cold drawing, extrusion, forging, welding (ERW/EFW), precision machining, specialized heat treatments.
C70600 (90/10) – Grades, Equivalents & Properties
Chemical Composition (Typical %):
| Element | Percentage |
|---|---|
| Copper (Cu) | 88.0 – 91.0 |
| Nickel (Ni) | 9.0 – 11.0 |
| Iron (Fe) | 1.0 – 1.8 |
| Manganese (Mn) | 0.50 – 1.0 |
| Zinc (Zn) | 1.0 max |
Mechanical Properties (Typical, Annealed):
| Property | Value |
|---|---|
| Tensile Strength | 40-55 ksi (275-380 MPa) |
| Yield Strength (0.5% Ext.) | 15-25 ksi (105-170 MPa) |
| Elongation | 35-50% |
| Hardness (Rockwell B) | 45-75 |
C71500 (70/30) – Grades, Equivalents & Properties
Chemical Composition (Typical %):
| Element | Percentage |
|---|---|
| Copper (Cu) | 68.9 – 72.0 |
| Nickel (Ni) | 29.0 – 33.0 |
| Iron (Fe) | 0.40 – 0.70 |
| Manganese (Mn) | 1.0 max |
| Zinc (Zn) | 1.0 max |
Mechanical Properties (Typical, Annealed):
| Property | Value |
|---|---|
| Tensile Strength | 55-75 ksi (380-520 MPa) |
| Yield Strength (0.5% Ext.) | 20-30 ksi (138-207 MPa) |
| Elongation | 30-45% |
| Hardness (Rockwell B) | 60-90 |
Properties: Superior corrosion and erosion resistance, especially in fast-flowing and turbulent seawater. Higher strength and better resistance to stress corrosion cracking than C70600. Good for higher temperature service.
C70600 vs C71500 – Comparison Summary
| Property | C70600 (90/10) | C71500 (70/30) |
|---|---|---|
| Copper (Cu) | 88.0 – 91.0% | 68.9 – 72.0% |
| Nickel (Ni) | 9.0 – 11.0% | 29.0 – 33.0% |
| Iron (Fe) | 1.0 – 1.8% | 0.40 – 0.70% |
| Tensile Strength | 40-55 ksi | 55-75 ksi |
| Yield Strength | 15-25 ksi | 20-30 ksi |
| Elongation | 35-50% | 30-45% |
| Hardness (HRB) | 45-75 | 60-90 |
| Biofouling Resistance | Excellent | Good |
| Corrosion Resistance (high-velocity) | Good | Superior |
| Cost | Lower | Higher |
Selection guidance: Choose C71500 for higher strength, superior erosion resistance in high-velocity and turbulent seawater, and better performance at higher temperatures. Choose C70600 for cost-sensitive projects with lower velocity seawater, where anti-fouling is the primary concern.
Applicable Specifications & Standards
| Category | Standards |
|---|---|
| Seamless Pipes/Tubes | ASTM B466 / B466M |
| Welded Pipes/Tubes | ASTM B467 / B467M |
| Seamless Condenser Tubes | ASTM B111 / B111M |
| Rod, Bar, and Wire | ASTM B151 / B151M |
| Plates, Sheets, Strips | ASTM B171 / B171M |
| Pipe Fittings | ASME B16.9, MSS-SP-43, ASME B16.11 |
| Flanges | ASME B16.5 / B16.47 |
| Pressure Piping Codes | ASME B31.1, ASME B31.3 |
| Material Traceability | EN 10204 3.1 |
Applications
Marine & Shipbuilding: Hull sheathing, seawater piping (bilge, ballast), heat exchangers, condensers
Offshore Oil & Gas: Piping, heat exchangers, subsea systems, firewater systems on platforms and FPSOs
Desalination Plants: Tubing in MSF and MED evaporators, brine heaters, heat exchangers
Power Generation (Condenser Systems): Steam condensers and heat exchangers in coastal power plants
Chemical & Petrochemical Processing: Applications involving mildly corrosive chemicals where chloride stress corrosion cracking is a concern
Refrigeration & HVAC: Heat exchanger tubing with brackish water or seawater cooling
Automotive Braking Systems: Brake lines for corrosion resistance and ductility
Quality Assurance & Testing
Certifications: ISO 9001:2015 certified. All products supplied with EN 10204 3.1 Mill Test Certificates (MTCs).
Testing includes:
Dimensional Accuracy: Verification against ASTM, ASME, and client specifications
Mechanical Testing: Tensile, yield, elongation, hardness
Chemical Analysis: Spectro analysis (PMI - Positive Material Identification)
Hydrostatic Testing: Mandatory for pipes, tubes, and pressure-retaining components
Eddy Current Testing: For seamless tubes to detect surface and subsurface defects
Flaring and Flattening Tests: For tubes, to assess ductility and weld integrity
Third-Party Inspection (TPI): Facilitated for TUV, BV, Lloyd's Register, SGS, DNV
FAQ
Q1: What are Copper Nickel Alloys C70600 and C71500?
C70600 (Cu-Ni 90/10) and C71500 (Cu-Ni 70/30) are copper-based alloys with nickel, iron, and manganese additions. They offer exceptional resistance to corrosion, erosion, and biofouling in seawater and brackish water, making them ideal for marine and industrial applications.
Q2: What industries use Cupro Nickel products?
Marine & shipbuilding, offshore oil & gas, desalination plants, coastal power generation (condenser tubing), chemical processing, refrigeration & HVAC, and automotive braking systems.
Q3: What is the difference between C70600 and C71500?
C70600 contains 10% nickel; C71500 contains 30% nickel. C71500 provides superior strength and enhanced resistance to erosion and impingement attack in higher velocity seawater. C70600 is preferred for its better anti-fouling characteristics and slightly higher thermal conductivity.
Q4: What product forms are available?
Pipes, tubes (seamless and welded), pipe fittings (butt-weld, socket weld, threaded), flanges (weld neck, slip-on, blind, socket weld, threaded, lap joint, orifice), bars (round, square, flat, hexagonal), and sheets/plates.
Q5: Is full material traceability provided?
Yes. Every shipment includes EN 10204 3.1 Mill Test Certificate (MTC) providing chemical analysis, mechanical test results, and inspection data of the specific heat batch.
Q6: What standards do these products comply with?
ASTM B466, B467, B111, B151, B171; ASME B16.9, B16.11, B16.5, B16.47; ASME B31.1, B31.3; EN 10204 3.1.
Production Equipment
| Equipment | Specifications | Purpose |
|---|---|---|
| Induction Melting Furnaces | 6 ton capacity, argon stirring | Precise control of chemical composition for C70600 (Ni 9-11%, Fe 1.0-1.8%) and C71500 (Ni 29-33%, Fe 0.40-0.70%) |
| Horizontal Continuous Caster | 200 mm billet diameter | Produces solid billet for pipe and tube extrusion |
| Extrusion Press | 3500 ton capacity | Pierces billet to form hollow pipe/tube shells |
| Hot Rolling Mill | Reversing type | Reduces plate and sheet thickness |
| Cold Pilger Mills | Multiple stands, up to 40m 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 (1200-1500°F), water quench | Produces annealed temper for C70600 and C71500; 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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