CuNi 90/10 (C70600) Stainless Steel Coil Tube – Marine Grade Copper-Nickel Alloy
Product Overview
The CuNi 90/10 (UNS C70600) Coil Tube is a premium marine-grade copper-nickel alloy tube supplied in continuous coil form by Wenzhou Jixing Metal Materials Co., Ltd. This product is specifically engineered for aggressive seawater environments, offering exceptional resistance to erosion-corrosion, biofouling, and pitting under high-velocity flow conditions. The coil configuration enables seamless forming, bending, and fabrication into complex geometries required in marine heat exchangers, condensers, and seawater distribution systems, thereby minimizing material waste and welding joints.
Material & Properties
The CuNi 90/10 alloy (C70600) consists of approximately 90% Copper (Cu) and 10% Nickel (Ni), with trace amounts of iron, manganese, and other residual elements. This composition provides a well-recognized balance of corrosion resistance, thermal conductivity, and mechanical strength in marine applications.
- Erosion-Corrosion Resistance: Withstands seawater flow velocities up to 2.5 m/s without significant material degradation, making it ideal for high-throughput marine cooling systems.
- Low Biofouling: The copper-rich matrix inhibits marine organism attachment and growth, reducing maintenance intervals and ensuring long-term hydraulic efficiency.
- Thermal Conductivity: Superior heat transfer performance (approximately 85 W/m·K) ensures efficient operation in condensers and heat exchangers.
- Galvanic Compatibility: Compatible with stainless steel and titanium components commonly used in marine systems.
- Ductility & Formability: Excellent cold-formability allows the coil tube to be precisely shaped without cracking or thinning.
Specifications
| Parameter | Specification |
|---|---|
| Alloy Designation | UNS C70600 / CuNi 90/10 / Admiralty Brass (Marine Grade) |
| Chemical Composition | Cu: 88.0–90.5%, Ni: 9.5–11.0%, Fe: ≤0.35%, Mn: ≤0.35%, Zn: ≤0.25%, Sn: ≤0.05% |
| Density | 8.85 g/cm³ |
| Tensile Strength | ≥290 MPa (annealed condition) |
| Yield Strength | ≥130 MPa (0.2% offset) |
| Elongation | ≥35% |
| Thermal Conductivity | ~85 W/(m·K) at 20°C |
| Electrical Resistivity | ~0.052 μΩ·m |
| Maximum Operating Temperature | 120°C (in seawater service) |
| Maximum Seawater Flow Velocity | 2.5 m/s (without erosion-corrosion) |
| Supply Form | Continuous Coil Tube (Coiltube) |
| Surface Condition | Smooth, annealed, or polished as specified |
| Applicable Standards | ASTM B151 / ASME SB151 / ASTM B152 / EN 12464 |
Manufacturing Process
The production of CuNi 90/10 (C70600) coil tube follows a rigorous multi-stage manufacturing sequence to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Ingot Casting: High-purity copper and nickel are melted and cast into ingots under controlled atmosphere conditions to minimize oxide inclusions.
- Hot Rolling: Ingots are hot-rolled into thick-walled seamless tubes, establishing initial wall geometry and homogenizing the microstructure.
- Cold Drawing / Extrusion: Tubes are cold-drawn through precision dies to achieve final dimensions and enhanced surface finish. The cold working process improves mechanical properties through strain hardening.
- Coiling: Finished tubes are wound onto precision coils using controlled tension systems to prevent deformation, kinking, or surface marring.
- Heat Treatment (Annealing): Controlled annealing relieves residual stresses, restores ductility, and stabilizes the grain structure for optimal formability downstream.
- Quality Inspection: Each coil undergoes ultrasonic testing (UT), hydrostatic pressure testing, chemical analysis, and dimensional verification before dispatch.
Applications
CuNi 90/10 (C70600) coil tube is the industry-standard material for critical marine and water-treatment systems. Key application domains include:
- Marine Condensers & Heat Exchangers: Primary tubing material for shipboard condensers, surface condensers, and heat recovery units operating in seawater-cooled environments.
- Seawater Desalination Pretreatment Piping: Used in intake lines, strainers, and pretreatment systems for reverse osmosis (RO) and multi-stage flash (MSF) desalination plants.
- Naval & Military Vessels: Cooling water circuits, ballast systems, and auxiliary heat exchangers on naval platforms.
- Offshore Platforms: Seawater cooling loops, fire-fighting systems, and HVAC condensers on offshore oil and gas installations.
- Power Generation: Condenser tubes in coastal thermal power plants utilizing seawater as a cooling medium.
- Aquaculture Systems: Seawater circulation and aeration piping where biofouling resistance is critical.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. ensures that all CuNi 90/10 (C70600) coil tube products comply with internationally recognized quality and industry standards:
- ISO 9001:2015 – Quality Management System certification ensuring consistent production quality.
- ASTM B151 / ASME SB151 – Standard specification for copper-nickel alloy seamless tube for heat transfer equipment.
- EN 12464 – European standard for copper-nickel alloy seamless tubes for heat exchangers and heat sinks.
- ASTM B152 – Standard for copper-nickel alloy pipe and tube (welded and seamless).
- DNV-GL / ABS / Lloyd's Register – Classification society approvals for marine applications.
- Mill Test Certificates (MTC): Full chemical analysis, mechanical test results, and dimensional verification provided with each batch.
- NDT (Non-Destructive Testing): Ultrasonic flaw detection and eddy current testing performed on all production lots.
Unique Selling Points
The CuNi 90/10 (C70600) coil tube from Wenzhou Jixing Metal Materials Co., Ltd. stands out through:
- Continuous Coil Supply: Eliminates the need for field welding on long runs, reducing leak points and installation labor while improving system reliability.
- Proven Marine Durability: Decades of field performance data validate service life exceeding 15–20 years in seawater applications with minimal maintenance.
- Superior Biofouling Resistance: Reduces chemical treatment requirements and maintenance downtime compared to stainless steel alternatives.
- Cost-Effective Lifecycle: Lower total cost of ownership due to extended service intervals, reduced energy consumption from maintained heat transfer efficiency, and minimal replacement frequency.
- Comprehensive Traceability: Full batch traceability from raw material to finished coil, backed by detailed mill certificates and third-party inspection options.