Picking the wrong tube material for a seawater cooling circuit can result in premature failure. Copper-nickel tube solves that problem. With natural resistance to chloride corrosion, biofouling, and thermal stress, it outlasts carbon steel and plain copper in aggressive wet environments. Copper alloy tubes are manufactured with precision for these tough conditions and cupro nickel grades remain among our most sought-after products for heat exchangers, condensers, and marine systems.
Copper Nickel 70/30 Tube
Thirty percent nickel changes everything about how copper behaves under heat and pressure. Copper Nickel 70/30 Tube carries that 70% copper, 30% nickel composition, giving it a tensile strength near 380 MPa and a continuous service ceiling around 300°C. Those numbers put it well above the 90/10 grade in mechanical terms. Engineers reach for Cupro Nickel 70/30 Tubes when the job involves steam condensers, offshore platform heat exchangers, or desalination pre-heaters where both pressure and saltwater exposure are daily realities.
Features of Copper Nickel 70/30 Tube
- Seawater corrosion resistance: Resists pitting and crevice attack in chloride-rich water at flow velocities up to 3.5 m/s, making it a standard choice for marine cooling loops.
- Tensile strength at 380 MPa: Higher tensile strength than 90/10 cupro nickel grade by about 20%, and can take higher internal pressures without distortion of the walls.
- Natural biofouling control: Copper ions in the alloy suppress barnacle and microbial attachment, cutting cleaning cycles on offshore condenser systems.
- Thermal conductivity of 29 W/m.K: Moves heat efficiently through tube walls, which directly improves exchanger performance in power plant condensers.
- Weldable without pre-heat: Accepts TIG and MIG welding under standard conditions, reducing fabrication time on site.
- ASME SB111 compliance: ASME SB111 Cupro Nickel Tube meets the code requirements for boilers and pressure vessels and can be purchased for projects on regulated plant.
- Near-unity magnetic permeability: Keeps magnetic interference low, which matters in instrumentation-heavy marine and offshore installations.
Copper-Nickel Alloys Are Used in the Following Areas
- Shell-and-tube heat exchangers and surface condensers in power stations
- Seawater desalination plant pre-heaters and evaporators
- Cooling circuits on offshore oil and gas platforms
- Naval vessel and submarine thermal management systems
- Hydraulic and instrument tubing in marine engineering
- HVAC condensers and refrigeration coil assemblies
- Chemical processing lines exposed to dilute acid or alkali media
Types of Copper Nickel Tube
Munot Metalloys stocks and manufactures copper-nickel tubing across six distinct product forms to match specific pressure ratings, installation methods, and heat transfer requirements.
- Seamless Copper Nickel Tube: No weld seam anywhere along the wall. Handles cyclic pressure and high-stress bending without seam failure. Available in OD sizes from 6 mm to 168 mm.
- Welded Copper Nickel Tube: Strip-formed and seam-welded for lower-pressure exchanger duty where cost per metre matters more than burst pressure margin.
- ASME SB111 Cupro Nickel Tube: Produced to ASTM B111 / ASME SB111 for code-compliant boilers, condensers, and heat exchangers in power and process plants.
- U-Bend Tube: Pre-formed into U-shape for direct drop-in fitment on U-tube heat exchangers, cutting on-site bending and fabrication hours.
- Finned Copper Nickel Tube: External fins increase the active surface area, pushing heat transfer rates up in air-cooled condensers and HVAC coil units.
- Straight Length Tube: Cut to 6 m standard lengths or project-specified dimensions for straightforward installation in custom exchanger builds.
Conclusion
Not every alloy survives saltwater, steam, and 300°C service at the same time. Copper Nickel 70/30 Tube does. From ASME SB111 Cupro Nickel Tube for code-regulated condensers to pre-bent U-tube forms for heat exchanger retrofits, Munot Metalloys produces each product to tight dimensional and compositional tolerances built up over 35 years of manufacturing. Reach out to our team for a product datasheet or to discuss grade and dimension requirements for your project.
