If you're sourcing copper nickel tubes, cupro nickel pipe, or cupronickel tubing for a USA marine, industrial, or offshore project, you're working with one of the most corrosion-resistant alloy systems available for seawater and harsh-environment applications. Getting the grade, size, and construction right before you order is what separates a successful specification from a costly one.

Browse Dexters Sales Inc.'s full range of copper, cupro nickel, and brass tubes and pipes — serving industrial and marine buyers across the USA, including New York — and use this guide to make the right call the first time.

What Is Cupro Nickel? The Short Version

Cupronickel (also written cupro nickel or copper nickel, abbreviated CuNi) is a copper-based alloy containing between 2% and 45% nickel, with small additions of iron and manganese that enhance corrosion resistance and strength. The result is a material that combines copper's thermal conductivity and workability with nickel's exceptional resistance to seawater corrosion, biofouling, and stress corrosion cracking.

The two commercially dominant grades — 90/10 (C70600) and 70/30 (C71500) — cover the majority of USA marine and industrial applications. A third grade, C715, is the military specification equivalent widely used in US Navy and defense applications.

Cupro Nickel Grades — Which One Do You Need?

GradeUNSCompositionKey PropertiesBest Applications90/10C7060090% Cu, 10% Ni, + Fe/MnExcellent seawater corrosion resistance, good weldability, cost-effective Seawater piping, heat exchangers, condensers, shipbuilding, desalination 70/30C7150070% Cu, 30% Ni, + Fe/MnHigher strength and corrosion resistance than 90/10; superior in high-velocity seawater High-pressure marine systems, naval vessels, offshore platforms, power plant condensers C715C71500 / MIL-T-16420K70% Cu, 30% Ni (military spec)Meets US Navy MIL-T-16420K Class 200 and Class 700 pressure specifications US Navy shipboard piping, military marine applications, defense procurement 

90/10 cupro nickel is the most widely stocked and specified grade in the USA for general seawater and marine piping applications — it provides excellent corrosion resistance at a lower cost per foot than 70/30. 70/30 is specified where higher strength and performance in more aggressive marine and high-velocity flow environments are required. C715 and the associated military pressure classes (Class 50, Class 200, Class 700) are the standard for US Navy procurement.

Copper Nickel Pipe vs. Copper Nickel Tube — What's the Difference?

The same distinction applies here as with other specialty metals:

Copper nickel tubes are specified by outer diameter (OD) and wall thickness — standard for heat exchanger tubes, condenser tubes, instrumentation tubing, and precision mechanical applications. Available in seamless construction for highest pressure ratings and tightest tolerances.

Cupro nickel pipe is specified by nominal pipe size (NPS) and pressure class — the standard for USA fluid conveyance piping systems in marine, industrial, and offshore applications. US standard pressure classes are Class 50, Class 200, and Class 700 per MIL-T-16420K.

Both are available in seamless (Type I) and welded (Type II) construction:

Seamless copper nickel tube/pipe — No weld seam; highest pressure rating; standard for critical marine, naval, and offshore applications

Welded cupronickel pipe — More cost-effective for larger diameters (typically 14" OD and above per US standards); suitable for lower-pressure and structural applications

Copper Nickel Pipe Sizes — US Standards

Cupro nickel pipe dimensions in the USA follow ASTM B466 and MIL-T-16420K standards. Standard size range runs from 1/8" nominal to 24" nominal in seamless and welded construction:Nominal SizeOD (mm)Available Pressure Classes1/4"13.72 mmClass 200, Class 700 1/2"21.34 mmClass 200, Class 700 1"33.4 mmClass 200, Class 700 2"60.32 mmClass 200, Class 700 4"114.3 mmClass 200, Class 700 6"168.3 mmClass 200, Class 700 8"219.1 mmClass 200, Class 700 12"323.9 mmClass 50, Class 200 14"–20"355.6–508.2 mmSeamless or Welded, Class 50, Class 200 22"–24"558.8–609.6 mmWelded Type II 

Copper nickel tubes for heat exchanger and condenser applications follow ASTM B111 — available from small-bore sizes starting at 3/8" OD through larger industrial diameters.

Primary Applications in the USA

Marine and Naval Shipbuilding: Copper nickel tubes and pipe are the material of choice for seawater piping systems, fire suppression systems, ballast systems, bilge systems, and exhaust cooling systems on commercial and naval vessels across the USA. The 90/10 grade handles most commercial shipbuilding applications; 70/30 and C715 are standard for US Navy vessels.

Heat Exchangers and Condensers: Cupronickel tubing is a benchmark material for heat exchanger and condenser tube bundles in power plants, desalination systems, offshore platforms, and HVAC systems — the combination of high thermal conductivity and seawater corrosion resistance makes it the go-to for these applications in the USA.

Offshore Oil and Gas: Offshore platforms and subsea systems across the Gulf of Mexico and other USA offshore zones specify cupro nickel pipe and tube for seawater cooling, fire water systems, hydraulic control lines, and process piping where saltwater exposure is continuous.

Desalination Plants: Multi-stage flash (MSF) and reverse osmosis desalination facilities in the USA and globally use copper nickel tubes for their heat transfer efficiency and long service life in hot brine and seawater environments.

Power Generation: Coastal and nuclear power plants use cupronickel condenser tubes and heat exchanger tubes — particularly 70/30 grade — for cooling water systems where seawater or brackish water is the coolant medium.

Automotive and Defense: Cupro nickel tubing is used in hydraulic brake lines, automotive cooling systems, and military vehicle hydraulic systems — applications where corrosion resistance and pressure performance in compact tube formats matter.

Key Standards for USA Procurement

When ordering copper nickel tubes or cupro nickel pipe in the USA, confirm that products meet the applicable standard for your application:

ASTM B111 — Standard for copper alloy seamless condenser tubes and ferrule stock; primary standard for heat exchanger and condenser tubing

ASTM B466 — Standard for seamless copper-nickel pipe and tube; primary standard for piping applications

ASTM B467 — Standard for welded copper-nickel pipe

MIL-T-16420K — US military specification for copper-nickel pipe, Class 50 / Class 200 / Class 700; required for US Navy procurement

ASME SB-111 / SB-466 — ASME pressure vessel and piping code equivalents for ASTM B111 and B466

What to Look for in a CuNi Tube Supplier

For USA marine and industrial buyers, the right copper nickel tube supplier is not simply the one with the lowest price per foot:

Grade and construction availability: A reliable cupro nickel pipe supplier stocks both 90/10 (C70600) and 70/30 (C71500) grades in seamless and welded construction across the standard USA size range. Military spec C715 / MIL-T-16420K availability is essential for defense and naval procurement.

Certifications and mill test reports: Every order of copper nickel tube for sale should come with full mill test reports (MTRs) confirming grade, chemistry, and mechanical properties per ASTM B111, B466, or MIL-T-16420K as applicable. For US Navy procurement, third-party inspection and NAVSEA-approved testing may also be required.

Cut-to-length and processing: Suppliers offering cut-to-length, bevel, and custom processing reduce fabrication lead time and handling costs for project-based orders.

Location and lead time: For USA projects requiring fast turnaround — particularly in the New York, New Jersey, and Gulf Coast markets — local or regional stocking suppliers reduce lead time significantly versus overseas direct shipment.

Dexters Sales Inc. serves USA marine and industrial buyers from Brooklyn, NY — browse copper, cupro nickel, and brass tubes and pipes here.

Additional Resources

For more detailed coverage of cupro nickel pipe grades, properties, and USA sourcing:

👉 Cupro Nickel Pipe & CuNi Tubes — Dexters Sales Inc. USA

👉 Cupro Nickel Pipes & Tubes — CuNi Suppliers for USA Marine & Industrial

FAQs

What is cupro nickel pipe used for?

Cupro nickel pipe is used in seawater piping systems, marine vessels, offshore platforms, heat exchangers, condensers, desalination plants, power generation cooling systems, and hydraulic and brake line tubing.

What is the difference between 90/10 and 70/30 copper nickel?

90/10 (C70600) contains 90% copper and 10% nickel — excellent seawater corrosion resistance at lower cost, suitable for most commercial marine applications. 70/30 (C71500) contains 70% copper and 30% nickel — higher strength and better performance in high-velocity seawater and more aggressive environments; standard for US Navy and offshore applications.

What is C715 cupro nickel?

C715 is the common trade designation for 70/30 copper nickel (UNS C71500) manufactured to US military specification MIL-T-16420K — required for US Navy shipboard piping and defense procurement in Class 200 and Class 700 pressure ratings.

What standard governs copper nickel pipe sizing in the USA?

ASTM B466 covers seamless copper-nickel pipe; ASTM B467 covers welded; MIL-T-16420K covers military specification pipe in Class 50, 200, and 700. Sizes range from 1/8" to 24" nominal in the US standard.

Can I buy copper nickel tubes in New York?

Yes — Dexters Sales Inc. in Brooklyn, NY stocks and supplies copper nickel tubes and cupro nickel pipe for USA marine and industrial buyers.

What certifications should I request when buying cupronickel tubing?

Request full mill test reports (MTRs) per ASTM B111 for heat exchanger tubes, ASTM B466 for pipe, or MIL-T-16420K for military applications. Third-party inspection certification may be required for US Navy procurement.