CuNi 70/30 & 2205 Duplex Marine Seawater Cooler Coil Tube
Product Overview
The Marine Seawater Cooler Coil Tube is a high-performance coil tube engineered specifically for marine engineering seawater cooling systems. Designed by Wenzhou Jixing Metal Materials Co., Ltd., this product addresses the extreme challenges of prolonged seawater immersion, including sustained temperatures exceeding 30°C, aggressive biological fouling, and high flow velocities of 2–3 m/s. The coil tube integrates advanced alloy composition with a specialized anti-biofouling surface design, ensuring long service life, minimal maintenance intervals, and reliable thermal transfer performance in the most demanding offshore and naval environments.
Material & Properties
This coil tube is available in two premium marine-grade alloy options, each selected for superior corrosion resistance, mechanical strength, and biocompatibility with seawater environments:
- CuNi 70/30 (Copper-Nickel 70/30): A classic marine alloy offering exceptional resistance to seawater corrosion, excellent resistance to biofouling, and outstanding thermal conductivity. The 70/30 copper-nickel composition forms a stable passive oxide layer that inhibits both galvanic and pitting corrosion, even at elevated temperatures above 30°C.
- 2205 Duplex Stainless Steel: A super duplex-free duplex alloy providing outstanding mechanical strength (yield strength up to 450 MPa), superior resistance to chloride-induced stress corrosion cracking, and enhanced durability under high-velocity seawater flow conditions. The dual-phase microstructure (austenite + ferrite) delivers an optimal balance of toughness and strength.
Anti-Biofouling Design
A defining feature of this coil tube is its integrated anti-biofouling design, which employs a precision-engineered surface finish and/or specialized surface treatment to minimize the adhesion of marine organisms such as barnacles, mussels, and algae. This design significantly reduces fouling-related heat transfer degradation and extends the operational interval between cleaning cycles, translating to lower lifecycle costs and improved vessel uptime.
Specifications
| Parameter | Specification |
|---|---|
| Product Type | Seawater Cooler Coil Tube |
| Application Category | Marine Engineering — Seawater Systems |
| Available Materials | CuNi 70/30 (C90800 / UNS C70600) | 2205 Duplex Stainless Steel (UNS S31803 / S32205) |
| Operating Seawater Temperature | Up to 30°C and above (continuous exposure) |
| Design Flow Velocity | 2–3 m/s |
| Corrosion Resistance | Excellent seawater corrosion resistance; resistant to pitting and crevice corrosion |
| Biofouling Resistance | Specialized anti-fouling surface design to inhibit biological attachment |
| Coil Diameter | Customizable per project requirements |
| Tube Wall Thickness | Customizable (typical range: 0.5–2.0 mm) |
| Outer Diameter | Customizable (typical range: 8–25 mm) |
| Surface Finish | Polished / anti-fouling treated |
| Welding Method | Continuous TIG (GTAW) or orbital welding |
| Standards Compliance | ASTM B151, ASTM B751, EN 10217-7, NORSOK M-650 |
Manufacturing Process
The production of this marine seawater cooler coil tube follows a rigorous, multi-stage manufacturing protocol to ensure dimensional accuracy, metallurgical integrity, and surface quality:
- Material Selection & Inspection: Ingot or billet materials are sourced from certified suppliers and subjected to spectroscopic analysis to verify chemical composition compliance with applicable ASTM/EN standards.
- Hot & Cold Forming: Seamless tubes are hot-rolled and subsequently cold-drawn to achieve precise outer diameter and wall thickness tolerances. For CuNi 70/30, hot forging followed by cold working ensures optimal grain structure and mechanical properties.
- Coil Winding: The formed tubes are cold-bent into precise coil configurations using CNC-controlled coil winding machinery to maintain uniform bend radius and eliminate residual stress concentrations.
- Welding: Continuous TIG (GTAW) welding is employed to join tube sections, ensuring full-penetration welds with minimal heat-affected zone distortion. Weld quality is verified through visual inspection and radiographic testing (RT) where required.
- Surface Treatment & Anti-Fouling Processing: The coil tube surface undergoes precision polishing and/or specialized anti-biofouling coating application to achieve the target surface roughness (Ra ≤ 0.4 μm) that minimizes biological adhesion.
- Heat Treatment (if applicable): 2205 duplex tubes may undergo solution annealing to optimize phase balance and relieve residual stresses introduced during forming.
- Final Quality Assurance: Every coil tube undergoes hydrostatic pressure testing, dimensional verification, surface inspection, and material certification review prior to shipment.
Applications
This seawater cooler coil tube is purpose-built for the following marine engineering applications:
- Naval Vessel Seawater Cooling Systems: Primary heat exchanger elements for engine cooling, hydraulic fluid cooling, and auxiliary system thermal management on naval ships, warships, and offshore support vessels.
- Offshore Platform Cooling Loops: Seawater cooling circuits for offshore oil and gas platforms, FPSO units, and subsea production systems where corrosion and biofouling resistance are critical.
- Marine Propulsion System Heat Exchangers: Compact coil tube assemblies for diesel engine seawater coolers, turbocharger coolers, and lubricating oil coolers on commercial and industrial vessels.
- Power Generation Seawater Intake Systems: Thermal management coils for marine power plants and shore-based desalination facilities utilizing seawater as a coolant medium.
- Subsea Equipment Cooling: Pressure-resistant coil tubes for subsea control modules, hydraulic systems, and electrical enclosures requiring passive cooling.
Quality Certifications & Compliance
Wenzhou Jixing Metal Materials Co., Ltd. maintains a comprehensive quality management system and holds the following certifications to assure customers of product reliability and regulatory compliance:
- ISO 9001:2015 — Quality Management System Certification
- ISO 14001 — Environmental Management System Certification
- ISO 45001 — Occupational Health & Safety Management System Certification
- ASME Stamp — Pressure Vessel & Piping Components Certification (where applicable)
- NORSOK M-650 — Materials for Use in the Petroleum Industry (offshore compliance)
- DNV-GL — Classification Society Approval for Marine Applications
- ABS / Lloyd's Register — Naval Architecture & Marine Engineering Certification
- Material Test Certifications: EN 10204 3.1 / 3.2 material certificates provided with every shipment, including chemical analysis, mechanical test results, and traceability documentation.
Key Selling Points
- Dual Material Options: Choose between the corrosion-resistant, thermally conductive CuNi 70/30 or the high-strength 2205 duplex stainless steel to match specific project requirements.
- Engineered Anti-Biofouling Surface: Purpose-designed surface treatment significantly reduces marine organism attachment, cutting cleaning frequency and extending operational intervals.
- Proven Performance in Harsh Seawater Conditions: Validated for continuous operation at 30°C+ seawater temperatures with 2–3 m/s flow velocities, ensuring long-term reliability.
- Full Customization Capability: Coil diameter, tube dimensions, and configuration are tailored to exact OEM specifications and project requirements.
- End-to-End Traceability: Complete material traceability from ingot to finished coil, backed by third-party inspection and certification.
- Global Marine Industry Compliance: Products meet or exceed the standards of major classification societies and offshore industry regulations.
Note: All specifications listed are subject to project-specific engineering requirements. Wenzhou Jixing Metal Materials Co., Ltd. offers full technical consultation and custom design support to ensure optimal coil tube performance for each marine application. Please contact our engineering team for detailed quotations, material certifications, and sample testing.