CuNi 90/10 (C70600) Copper-Nickel Alloy Coil Tube
Product Overview
Wenzhou Jixing Metal Materials Co., Ltd. presents its premium CuNi 90/10 (C70600) coil tube, a high-performance copper-nickel alloy tubing product specifically engineered for the most demanding marine and offshore environments. Designed to withstand prolonged exposure to seawater and aggressive chloride-rich media, this coil tube delivers exceptional resistance to flow-induced corrosion, pitting, and crevice attack — making it the material of choice for shipbuilding, marine heat exchange systems, and seawater desalination infrastructure.
Supplied in continuous coil form, this product offers superior installation efficiency and material utilization, reducing welding joints and minimizing potential failure points in critical piping systems. The 90% copper / 10% nickel composition provides an optimal balance of mechanical strength, thermal conductivity, and corrosion resistance that outperforms standard austenitic stainless steels in seawater applications.
Material & Properties
CuNi 90/10 (C70600) is a wrought copper-nickel alloy that benefits from the synergistic protective effects of both copper and nickel. The high nickel content (10%) forms a stable, self-healing passive oxide film on the alloy surface, providing outstanding resistance to biofouling and microbiologically influenced corrosion (MIC). This alloy is fully compliant with ASTM B151/B151M, ASTM B751, EN 12735-2, and ISO 21092 standards.
- Composition: 90% Copper (Cu), 10% Nickel (Ni), with trace amounts of iron, zinc, and manganese
- Specific Gravity: 8.9 g/cm³
- Thermal Conductivity: 25.7 W/(m·K) at 20°C
- Electrical Resistivity: 6.25 × 10⁻⁶ Ω·m
- Operating Temperature Range: −40°C to +150°C (short-term up to 200°C)
- Corrosion Resistance: Excellent resistance to seawater flow-induced corrosion (up to 2 m/s), freshwater, brackish water, and mildly acidic/alkaline environments
- Biofouling Resistance: Inherently low susceptibility to marine organism attachment due to copper's oligodynamic effect
Specifications
| Parameter | Specification |
|---|---|
| Alloy Designation | CuNi 90/10 (C70600 / CW4440) |
| Product Form | Coil Tube (Continuous Coil) |
| Outside Diameter (OD) | 6.0 mm – 108 mm (custom sizes available) |
| Wall Thickness | 0.5 mm – 6.0 mm |
| Coil Length | 10 m – 100 m per coil (configurable) |
| Tensile Strength | ≥ 310 MPa (annealed condition) |
| Yield Strength (0.2% offset) | ≥ 110 MPa |
| Elongation at Fracture | ≥ 35% |
| Hardness | ≤ 90 HRB (annealed) |
| Tolerance (OD) | ±0.05 mm to ±0.15 mm (per EN 12735-2) |
| Tolerance (Wall) | ±0.10 mm |
| Surface Finish | Smooth, bright, or matte (as required) |
| Maximum Seawater Flow Velocity | 2.0 m/s (without erosion-corrosion) |
| Standards Compliance | ASTM B151, ASTM B751, EN 12735-2, ISO 21092 |
Manufacturing Process
The CuNi 90/10 coil tube is produced through a rigorous multi-stage manufacturing process to ensure dimensional accuracy, metallurgical integrity, and consistent corrosion performance:
- Alloy Casting & Ingot Production: High-purity copper and nickel are melted in vacuum or argon-protected furnaces to minimize oxide inclusions and ensure homogeneous alloy composition.
- Hot Rolling & Extrusion: Billets are hot-rolled and/or extruded to produce seamless tubes to the required nominal dimensions.
- Cold Drawing & Forming: Tubes are cold-drawn through precision tooling to achieve tight dimensional tolerances and enhanced mechanical properties.
- Coil Winding & Annealing: Drawn tubes are carefully coiled and subjected to controlled solution annealing (typically 700°C – 750°C in a protective atmosphere) to relieve cold-work stresses and restore full ductility.
- Pipe Inspection: Each coil undergoes 100% hydrostatic pressure testing, eddy current inspection, and visual examination to detect internal or external defects.
- Surface Treatment: Tubes are cleaned, pickled, and passivated to remove surface contaminants and ensure optimal corrosion resistance from delivery.
- Coil Packaging: Finished coils are wrapped in protective film, secured with strapping, and packed on wooden reels for safe transport.
Applications
CuNi 90/10 coil tube is the industry-standard material for a wide range of marine and industrial applications where seawater corrosion resistance is critical:
- Ship Condensers & Heat Exchangers: Primary and secondary condensers in marine propulsion systems, power generation vessels, and offshore platforms
- Seawater Desalination Plants: Pre-treatment piping, heat recovery exchangers, and cooling water circuits in multi-stage flash (MSF) and reverse osmosis (RO) systems
- Marine Cooling Systems: Sea water intake piping, jacket water coolers, and auxiliary cooling circuits on naval and commercial vessels
- Offshore Oil & Gas Platforms: Subsea cooling circuits, ballast water systems, and seawater circulation lines
- Chemical Processing: Equipment handling non-chloride-containing acids, alkalis, and ammonia solutions
- Power Generation: Cooling water systems in coastal thermal power stations and nuclear facilities
- Brackish Water & Wastewater Treatment: Distribution piping and heat exchangers in municipal and industrial water treatment plants
Quality Certifications
Wenzhou Jixing Metal Materials Co., Ltd. maintains rigorous quality management systems and holds the following certifications to assure product reliability:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001:2015 — Environmental Management System Certification
- EN 10204 3.1 — Material Test Certificate (MTC) with third-party inspection
- CE Marking — Compliance with European directives for pressure equipment and marine components
- ABS / DNV / Lloyd's Register — Class society approval for marine applications (available upon request)
- Mill Test Reports (MTR) — Full chemical analysis and mechanical test data provided with every shipment
Key Selling Point: CuNi 90/10 coil tube from Wenzhou Jixing offers superior seawater corrosion resistance, low biofouling susceptibility, and high thermal conductivity — all in a continuous coil format that reduces installation time and eliminates unnecessary weld joints. This makes it the ideal choice for shipbuilders, desalination plant engineers, and offshore platform designers who demand long service life and minimal maintenance in marine environments.