Copper-Nickel 90/10: Complete Properties & Application Guide

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Overview

Copper-Nickel 90/10 (UNS C70600) is a cupronickel alloy offering good resistance to seawater corrosion and biofouling at a lower cost than 70/30. The iron addition enhances impingement corrosion resistance, making it the workhorse alloy for marine heat exchanger tubing.

Chemical Composition

The chemical composition of Copper-Nickel 90/10 is carefully controlled to achieve its unique combination of properties and performance characteristics.

Element	Min %	Max %
Copper (Cu)	Balance	Balance
Nickel (Ni)	9.0	11.0
Iron (Fe)	1.0	1.80
Manganese (Mn)	—	1.0
Zinc (Zn)	—	1.0
Carbon (C)	—	0.05
Lead (Pb)	—	0.05

Mechanical Properties at Room Temperature

The mechanical properties of Copper-Nickel 90/10 vary depending on product form and heat treatment condition. The data below represents typical values for solution-annealed material.

Property	Value
Tensile Strength	310 MPa
Yield Strength (0.2% offset)	105 MPa
Elongation in 2 inches	42%
Density	8.94 g/cm3
Melting Point	1150 °C
Max Service Temperature	300 °C

Corrosion Resistance

Excellent resistance to seawater corrosion and biofouling. Good resistance to pitting, crevice corrosion, and stress corrosion cracking in chloride environments. The protective oxide film forms naturally and heals quickly if damaged.

Applications

The unique combination of properties makes Copper-Nickel 90/10 suitable for a wide range of demanding applications:

• Heat Exchangers: Condenser and heat exchanger tubing in marine environments.
• Shipbuilding: Seawater cooling piping, bilge and ballast systems.
• Offshore: Seawater injection lines and firewater systems.
• Power Plants: Condenser tubing in coastal and estuarine power stations.
• Desalination: Brine heater tubing and flash chamber components.

Available Product Forms

Hangbo Alloy Group manufactures and supplies Copper-Nickel 90/10 in the following product forms, conforming to ASTM, AMS, and ASME specifications:

• Round Bars: Diameters from 6 mm to 300 mm, hot-finished or cold-drawn, solution annealed.
• Seamless Tubes & Pipes: Sizes from 6 mm OD to 219 mm OD, various wall thicknesses.
• Plates & Sheets: Thicknesses from 0.5 mm to 50 mm, hot-rolled or cold-rolled.
• Forgings: Custom flanges, rings, discs, and complex shapes per customer drawing.
• Welding Wire: Diameters 0.8 mm to 5.0 mm, precision-wound coils and spools.

Related Standards

Standard	Description
ASTM B111	Condenser Tube
ASTM B466	Seamless Pipe
ASTM B467	Welded Pipe
ASTM B122	Plate, Sheet, and Strip
ASTM B151	Bar and Rod
ASTM B171	Plate

Seawater Performance and Design Limits

Copper-nickel 90/10 forms a thin, self-healing oxide film that resists both general seawater corrosion and biofouling — the reason it is the default tube material for marine heat exchangers and condenser tubing.

Parameter	Typical limit
General corrosion rate (seawater)	< 0.025 mm/yr
Max water velocity, continuous	2.5–3.0 m/s
Max velocity, intermittent / erosion risk	4.0 m/s
Max service temperature	≈ 300 °C
Sulphide-bearing (polluted) water	Avoid — film breakdown

Keep velocities below the erosion-corrosion threshold and avoid stagnant conditions during commissioning; most 90/10 failures trace back to under-deposit attack or sulphide contamination rather than to the alloy itself. Watch galvanic effects when coupling to more noble materials.

Fabrication and Welding Guidance for Cu-Ni 90/10

• Cleanliness is critical — remove all grease, paint marker and sulphur-bearing lubricants before welding.
• Use GTAW with ERCuNi filler (AWS A5.7) or GMAW with ECuNi for production tube-to-tubesheet work.
• No preheat on thin sections; 150–200 °C on heavy plate to avoid porosity from hydrogen pickup.
• Shield with argon and back-purge tube bores — an unshielded root will oxidise and fail expansion.
• Avoid contact with carbon steel tools and fixtures; embedded iron particles initiate localised pitting.

Frequently Asked Questions

Why is 90/10 preferred over 70/30 for heat exchanger tubes?

90/10 delivers adequate seawater resistance at lower material cost and higher thermal conductivity, which matters for heat-transfer efficiency. 70/30 is specified where velocities are higher or erosion risk is significant.

Can copper-nickel be used in polluted or brackish water?

Only with care. Sulphides and ammonia break down the protective film and cause rapid attack. In those conditions, specify 70/30, increase wall thickness, or move to a high-molybdenum stainless or nickel alloy.

What standards cover 90/10 tube?

ASTM B111 / B466 for seamless tube and pipe, ASTM B171 for plate, and MIL-T-16420 for naval systems. Hangbo supplies to these with full EN 10204 3.1 certification.

What is the chemical composition of Cu-Ni 90/10?

UNS C70600 / W.Nr. 2.0872: copper balance, 9-11% nickel and 1.0-1.8% iron, with manganese up to 1.0%.

Why is 90/10 the workhorse for heat-exchanger tube?

The iron addition improves resistance to seawater impingement, and the alloy resists biofouling at lower cost than 70/30.

What are its mechanical properties?

Tensile about 310 MPa, yield about 105 MPa and 42% elongation in the annealed condition.

What standards cover Cu-Ni 90/10?

UNS C70600 / W.Nr. 2.0872, with ASTM B111 covering seamless tube for condensers and heat exchangers.

What is the maximum service temperature?

About 300 °C in seawater cooling duty.

How is 90/10 supplied?

Seamless and welded tube, pipe, plate and fittings for marine and desalination systems.

Contact Us for Copper-Nickel 90/10

Hangbo Alloy Group maintains extensive inventory of Copper-Nickel 90/10 in all standard product forms. We can provide mill test certificates, third-party inspection reports (SGS, TUV), and custom processing services.

For quotations, material certifications, or technical consultation, contact our sales team or call +86 166 2109 2936. We typically respond within 10 minutes.