Shanghai, June 2025 — In a major advancement for thermal management and fluid transfer systems, Chinese manufacturers are now offering CuNi 90/10 (C70600) and CuNi 70/30 (C71500) square and rectangular nickel copper alloy tubes, specifically engineered for cooling fin applications. With a standard wall thickness of 2mm and availability in both square and rectangular cross-sections, these precision-engineered tubes are setting new performance standards in heat exchangers, marine condensers, power plants, and industrial cooling systems.
The Importance of Cooling Fins in Thermal Engineering
Cooling fins are essential components in systems that rely on heat dissipation. From HVAC units and radiators to power electronics and desalination systems, the efficiency of a cooling fin determines how well excess heat is removed from critical operations.
To optimize heat transfer, materials used for cooling fin tubing must exhibit:
High thermal conductivity
Strong corrosion resistance
Resistance to biofouling and scaling
Mechanical integrity under thermal and pressure stress
Enter CuNi 90/10 and 70/30 rectangular tubes—metals known not just for their functional properties, but also for their adaptability in extreme environments, including seawater, chemical vapor, and high-humidity coastal zones.
CuNi 90/10 (C70600) vs. CuNi 70/30 (C71500)
These two copper-nickel alloys are industry favorites due to their long-term stability and corrosion resistance:
CuNi 90/10 (C70600): Composed of 90% copper and 10% nickel, with small additions of iron and manganese. This alloy provides excellent corrosion resistance in seawater, brine, and mild acidic environments, making it ideal for marine cooling fins and low-to-medium pressure systems.
CuNi 70/30 (C71500): With 70% copper and 30% nickel, this alloy offers enhanced strength and greater resistance to high-velocity seawater and aggressive industrial chemicals. It is preferred for high-performance condensers, power station piping, and chemical process lines.
Both alloys meet international specifications such as ASTM B111, B466, EEMUA 234, and DIN 86019, ensuring global compatibility for OEM and custom cooling systems.
Why Square and Rectangular Tubes?
Traditionally, round tubes have been the default shape in thermal systems. However, square and rectangular tubes offer several engineering advantages when used in cooling fin systems:
Increased surface area for heat transfer
Improved airflow and fluid dynamics
Compact and modular design integration
Easier stacking or fin mounting
Custom layout flexibility for limited spaces
The 2mm wall thickness provides an optimal balance between structural strength and thermal conductivity, ensuring performance even in high-pressure or vibration-intensive systems.
Applications Across High-Performance Industries
The use of CuNi rectangular tubing for cooling fins is growing across sectors that demand high thermal performance and long-lasting materials:
Marine & Offshore: Used in heat exchangers, seawater-cooled condensers, and ballast water treatment systems.
Power Generation: Ideal for turbine condenser cooling fins, nuclear plant systems, and waste heat recovery.
Chemical Processing Plants: Suited for environments with acidic or saline vapors, where corrosion resistance is vital.
HVAC and Refrigeration: Integrated into compact fin-and-tube heat exchangers in commercial buildings and industrial chillers.
Desalination Facilities: Performs exceptionally well in high-salinity, biofouling-prone environments.
Manufacturing Process: Precision and Purity
Chinese manufacturers such as TOBO Industrial (Shanghai) Co., Ltd. are leveraging advanced extrusion and cold drawing technologies to produce high-precision CuNi tubes. The production process includes:
Billet Casting & Extrusion
Cold Drawing for dimensional accuracy
Annealing for grain structure optimization
Pickling and Passivation to enhance corrosion resistance
Final Dimensional Inspection and Pressure Testing
All tubes undergo hydrostatic and eddy current testing, and are delivered with EN 10204 3.1/3.2 MTCs, verifying full compliance with global standards. Custom fabrication services include:
Tailored lengths and bending
Square/rectangular shaping
Fin welding and integration
CNC end processing
Technical Specifications at a Glance
Material: CuNi 90/10 (C70600) and CuNi 70/30 (C71500)
Shape: Square or Rectangular
Wall Thickness: 2mm standard (customizable)
Size Range: From 10×10 mm to 100×50 mm (and beyond)
Standards: ASTM B111 / B466 / B552, EEMUA 234, DIN 86019
Finishing: Bright annealed, polished, or passivated
Test Certificates: ISO 9001, TUV, SGS, DNV, ABS available
Market Dynamics and Global Supply
Driven by the rise of clean energy projects, modular industrial cooling systems, and marine technology upgrades, the demand for copper-nickel rectangular tubes has grown steadily over the past five years. China remains the world’s largest producer of copper-nickel tubing, supplying OEMs and EPC contractors in Europe, Southeast Asia, the Middle East, and South America.
Bulk orders for 2mm rectangular tubes are now fulfilled with short lead times and competitive pricing. Suppliers offer FOB, CIF, and DDP shipping terms, with full documentation support including certificate of origin, customs codes, and product traceability.
Sustainability and Lifecycle Value
Copper-nickel alloys are 100% recyclable, contributing to greener supply chains and environmental compliance. With a service life of 20–50 years depending on conditions, CuNi tubes drastically reduce maintenance costs and system failures compared to carbon steel or aluminum alternatives.
The material’s resistance to zincification, pitting, and stress corrosion cracking further ensures long-term stability, especially in salt-heavy or chlorinated systems.
Final Thoughts
The emergence of CuNi 90/10 and 70/30 rectangular and square tubes is a game-changer for thermal systems that depend on reliability, efficiency, and resilience. With excellent corrosion resistance, formability, and thermal performance, these tubes are enabling engineers to design better, last longer, and operate smarter—particularly in environments where standard metals cannot survive.
As industries around the world invest in next-generation heat exchange technology, nickel-copper alloy tubes for cooling fins will remain an integral solution to modern engineering challenges.