Copper Nickel Tube

copper-nickel-pipe-processing-lineCopper nickel tubes

A copper nickel tube is made from an alloy of copper that contains a high percentage of nickel. Apart from copper and nickel, there are other elements added to the alloy, such as iron or manganese. These serve the purpose of making the alloy stronger.

Applications/uses of copper nickel tubes

In the past few years, copper nickel tubes have started to be used in more and more industries, give their high resistance to corrosion (especially in seawater). Copper nickel tubes are used in the following domains:

  • For the making of complex piping systems (high-pressure water heaters, sea water piping – ships)
  • As essential elements in heat exchangers (naval vessels)
  • For condensers
  • Seawater systems
  • Marine hardware
  • In the making of boats
  • In desalination plants (evaporators)
  • For power stations or thermal power plants
  • Offshore structures
  • For the building of air cooling zones.

Often times, copper nickel tubes are used in heat exchangers on naval vessels. Heat exchangers are actually represented by a set of tubes. These are mounted between tube plates. The whole ensemble is arranged so that it will fit under a protective coverage. The heat exchanger has special holes through which the gas/liquid can enter or exit. The main purpose is for the gas or liquid to be either cooled down or heated. Sometimes, the copper nickel tubes are cooled through internal processes (water-based). In such situations, each tube plate has a water box outside, for the cooling process.

Copper nickel tubes are used in heat exchangers that function through seawater cooling. There are several reasons why copper nickel tubes are chosen, including the high resistance to corrosion (especially since the cooling is done with seawater), the guaranteed strength and flexibility and the life-time resistance. Plus, copper nickel tubes are well known to be resistant against marine deposits, without their integrity being affected.

Titanium – material for heat exchangers tubes

The copper nickel alloy is not the only material used for tubes in heat exchangers. As a matter of fact, titanium is often considered an alternative material to the copper nickel alloy. Titanium is chosen as material for the making of heat exchanger tubes that are going to be used in desalination plants. Just like copper nickel, it delivers an exceptional resistance to corrosion (even in highly corrosive environment, such as seawater).

Any plant that uses a cooling system based on seawater can benefit from the excellent performance titanium delivers. This is the reason why titanium tubes are often found in heat exchangers from desalination plants. Moreover, given its high resistance to corrosion and its existent mechanical properties, using titanium for the making of tubes has allowed for the thickness of the tube walls to be considerably reduced.

As a material chosen for the making of heat exchangers tubes, titanium can guarantee a better rate for the heat transfer, being light and strong. However, it should be mentioned that the heat transfer is not as good as the one delivered by the copper nickel alloy. Also, its specific gravity is half of the copper nickel alloy. Other differences are represented by the coefficient of thermal expansion (almost twice than the one of copper nickel) and the specific heat (bigger than the one of copper nickel).

Returning to the main subject, it should be mentioned that there are two types of copper nickel tubes. The first is C70600 (90/10) and the second is C71500 (70/30). Both of these two types have different mechanical and chemical properties. The first one to have been developed is the 70/30 (1920), being used in condensers for naval vessels. The second is the 90/10 (1950), being used for seawater piping.

Mechanical and chemical properties of copper nickel alloys

Mechanical and chemical properties 70/30 Copper Nickel 90/10 Copper Nickel
Density 8.94 g/cm3 8.94 g/cm3
Elastic modulus 150 GPa 140 GPa
Electrical conductivity 5% IACS 9% IACS
Elongation at break 3-36% 3-35%
Melting onset 1170 °C 1100 °C
Shear modulus 57 GPa 52 GPa
Specific heat capacity 380 J/kg-K 380 J/kg-K
Strength to weight ratio 43-65 kN-m/kg 39-63 kN-m/kg
Tensile strength (ultimate) 380-580 MPa 350-565 MPa
Tensile strength (yield) 125-545 MPa 63-90 MPa
Thermal conductivity 29 W/m-K 40 W/m-K
Thermal diffusivity 9 12
Thermal expansion 16.2 µm/m-K 17.1 µm/m-K

Table source: Make it From

ASTM B111 applicable production standards

The applicable production standards are included within the ASTM B111. This includes the standard specifications for copper alloys, used in general for the making of seamless condenser tubes and Ferrule stock. The specifications related to the copper nickel tubes that are found in naval condensers, evaporators and heat exchangers.

The standard specifications include the chemical requirements for different types of copper nickel alloys, including C70600 and C71500. The first one should have, besides copper, nickel between 9 and 11 and the following as strengthening elements (lead, iron, zinc and manganese). As for C71500, this has copper as primary element, nickel between 29 and 33 and similar strengthening elements as the other one.

Related to tensile requirements, C70600 should exhibit a tensile strength of 45 and yield strength of 35. As for C71500, this should deliver a tensile strength of 52 and a value for 18 for the yield strength. According to the ASTM B111 standard specifications, C70600 can be supplied in two different types of temper, meaning light drawn or annealed. The expansion requirements are as follows: 30 for C70600 and 20 for C71500.

The standard specifications also include the tests that can be made in order to assess the quality standards of the copper nickel tubes. Among these tests, there are: expansion test, flattening test, mercurous nitrate test and non-destructive testing. ASTM B111 also presents the dimensions and permissible variations, delivering useful information about the following aspects: diameter tolerance, wall thickness tolerance and tube length tolerance. Details regarding the density of copper alloys are also presented.

In conclusion, copper nickel tubes are 100% recommended for seawater cooling systems, given their high resistance to corrosion. They also prevent algae and creatures of the marine life (such as mollusks) from destroying their quality. The one thing to keep in mind is that they are not that resistant when the seawater is polluted or stagnant. In order to maintain the quality standards for the copper nickel tubes, it is for the best to avoid such conditions.



Copper Nickel Tube

copper nickel tubeCopper Nickel Tube available to the widest size range of outside diameter, length and wall thickness.

Seamless Copper Nickel pipes (CU NI) available in an Outside Diameters between 0.5mm to 330mm.

Welded Copper Nickel pipes available in an Outside Diameter range of 100 mm 2m and manufactured upto lengths of 15m ! Welded tubing is offered with single continuous weld lines.

North Steel Co. maintain a large stock program of cupronickel billets and tube billets to enable rapid production of tubes to fast delivery times.

Custom Cu Ni composition and tolerance levels are available subject to minimum orders with further information available from the customer service team.

Product RangeGalleryCuNi GradesNorth Steel CuNiApplicationsSupply

Copper Nickel Tube Production Capability

The following list gives details of our production capability. For custom and specialist tubes contact our sales team for further information.

  • Cu-Ni Tube Standards: ASTM B111
  • Cu-Ni Tube Type: Welded Tube / Seamless Tube
  • Cu-Ni Material: Cu-Ni 90/10, Cu-Ni 70/30
  • Cu-Ni Seamless Tube Dimensions:
    • Outer Diameter Range: 5 – 330 mm
    • Wall Height Range: 0.4 – 10 mm
    • Length Range: < 15000 mm
  • Cu-Ni Welded Tube Dimensions:
    • Outer Diameter Range: 100 – 5,000 mm
    • Wall Height Range: 0.4 – 100 mm
    • Length Range: < 15000 mm
  • We also follow the National Pipe Standards and hold a large stock to meet immediate demand.
  • Monthly Output: 2,000 tonnes
  • Rating: 4.6 / 5 based on 8 customer reviews


Copper Nickel Processing Line
Copper Nickel ASTM Standard Tubing

Copper Nickel Standards and Composition

Trade Name UNS Copper Nickel Industry Specifications Chemical Composition Min.Tensile
CuNi 90/10 UNS C70600
UNS C70620
ASME SB111, SB171, SB359, SB395, SB466, SB467, SB543
ASTM B111, B122, B151, B171, B359, B395, B432, B466, B467, B543, B608 DIN 2.0872 MIL C-15726, T-15005, T-16420, T-22214 SAE J461, J463
Cu 88.6 min
.05 max*
Fe 1.8 max
1 max*
Ni 9-11 max
Mn 1.0 max
38 15 30
CuNi 90/10 UNS C7060X EEMUA 144 90/10, 145 90/10, 14 90/1 Cu rem.
 .01 max
Fe 1.5-2.0
Zn 0.2 max
P 0.2 max
S 0.2 max
Ni 10-11
Mn 0.5-1.0
40 15 30
CuNi 70/30 UNS C71500
UNS C71520
ASME SB111, SB171, SB359, SB395, SB466, SB467, SB543
ASTM B111, B122, B151, B171, B359, B395, B432, B467, B543, B552, B608, F467, F468
DIN 2.0882
MIL C-15726, T-15005, T-16420, T-22214
SAE J461, J463
Cu rem (65.0 min)
 .05 max*
Fe 0.4-1.0
Zn 1 max*
Ni 29-33
Mn 1 max
 52 18 45
CuNi 70/30 UNS C71640 ASTM B111, B543, B552 Cu rem 
 .05 max*
Fe 1.7-2.3
Zn 1 max*
Ni 29-32
Mn 1.5-2.5
63 25

North Steel CuNi

Copper nickel tube tube production in large volumes and to short lead times requires great engineering excellence and one in which we excel. Such is our passion and dedication for cutting edge technology and engineering for cu-ni pipe manufacture we have won several regional and national awards in China for the production and supply of copper nickel piping. We understand the great need to evolve our copper nickel pipe production processes and our techniques and we continually look to invest in the most state of the art copper nickel tube equipment and machinery along with the extensive training that all of our engineering and technical personnel undergo.

cu-ni-tubes-heat-exchangerYou can find our copper nickel tubes at work in a whole variety of industries and applications from the core tubing in heat exchangers, frames in aerospace airframes, implants and medical equipment and in bicycle frames. We have worked hard over the years to build a reputation as one of the leading suppliers and manufacturers of Cu-Ni pipe and tube. To find out more on how we can support you copper nickel tube supply contact us today !

We are extremely proud of our tube production capabilities and have invested heavily in the future as we believe cu-ni tubing will play a key part in developing technologies. This along with our commitment to service excellence we believe is the reason why our customers keep choosing us for their tubing and piping requirements.Our large annual production volume of cupronickel tube allows us to maintain a large stock program inventory. We can meet customer requirements and expectations with rapid production of tubes and fast delivery times.

Copper Nickel Tube Applications

Cu-Ni alloys are alloys of copper (base metal with the largest individual content) and nickel with or without other elements, whereby the zinc content may not be more than 1%. When other elements are present, nickel has the largest individual content after copper, compared with each other element. As with other copper alloys, it is necessary to distinguish between wrought alloys, which are processed to semi-finished products, and cast alloys, from which castings are produced by various casting processes. The Cu-Ni alloys with additions of manganese are important in electrical engineering. Additions of iron significantly improve the resistance of Cu-Ni alloys to erosion corrosion in flowing seawater and other aggressive waters.
Copper Nickel Applications

  • Desalination
  • Seawater Piping Systems
  • Copper Nickel Corrosion Resistance

Copper alloys have very good resistance to seawater, brine water, organic compounds, salts, diluted non-oxidizing acids, and more. CuNi 90/10 (C70600 & C7060X) is a Copper Nickel Iron alloy with a small content of manganese which allows excellent resistance to sea- and brakish water. Of all commercial coper alloys, CuNi 70/30 (C71500) offers the best resistance to aqueous corrosion. It is resistant to acid solutions and highly resistant to stress corrosion cracking, and impingement corrosion. In addition, CuNi70/30 offers a greater strength for higher pressures.

copper-nickel-pipe-production-lineCupronickel (copper nickel) is an alloy of copper, nickel and strengthening elements such as iron and manganese. Cupronickel exhibits superior corrosion resistance in seawater. Because of this, it is used for marine hardware, piping systems and sometimes for the propellers, crankshafts and hulls of premium tugboats, fishing boats and other working boats.

The cupronickel alloy technology has been known by the Chinese since the third century BC under the name white copper and was used in corrosive environments. It is still used extensively in modern boat building. Cupronickel is uniquely qualified as an ideal candidate for piping systems in the ship-building industry due to its alloy properties, including low general corrosion rates in seawater, resistance to stress corrosion cracking due to ammonia in seawater, high resistance to crevice corrosion and stress corrosion due to chlorides, good pitting resistance, ready weldability, ease of fabrication and inherent resistance to biofouling. In some cases, cupronickel seawater piping systems can last a ship’s lifetime.

Copper Nickel Heat Resistance

The hot strength of copper increases with only a small addition of nickel. By adding iron, mechanical properties are improved, not only at room temperature, but also at elevated temperatures. 10% Ni. CuNi10Fe1Mn, for example, can be used in pressure vessel construction up to 300°C, CuNi30Mn1Fe up to 350°C. Above these limit temperatures, strength drops markedly, particularly the creep strength and creep strain limit.

Copper Nickel Heat Treatment

In general, heat treatments are only used with Cu-Ni alloys for soft annealing and stress relieving. Temperatures for recrystallisation annealing can vary over wide limits between about 620 and 900°C, depending on degree of cold work, nickel content and additional constituents. High temperatures are associated with short annealing times (continuous annealing) and low temperatures with long annealing times (static annealing). Stress-relief annealing is carried out at 280 to 500°C. It is advisable to anneal excluding air or in a slightly reducing atmosphere, to avoid the pickling that is required with air-containing annealing atmospheres.

Table 1. This summary covers American (ASTM), European (EN – replaces all previous national standards) and International Standards (ISO).
Standards Applicable Standard Numbers
Composition Plate Sheet Strip Tube Rod Wire Forgings Castings
ASTM 122
122 122 111
EN 1652
12163 12420 1982
ISO 429 1634 1634 1634 1635,
1637 1639 1638 1640
‡ 70-30 alloy only
§ 90-10 alloy only
Table 2. Standard Compositions of Wrought Cu-Ni Alloys (UNS Copper Alloy Numbers) Maximum or range.
UNS Number
Cu Pb Fe Zn Ni (incl Co) Mn Other
C70600 Rem 0.05* 1.0-1.8 1.0* 9.0-11.0 1.0 *
C71500 Rem 0.05* 0.4-1.0 1.0* 29.0-33.0 1.0 *
C71640 Rem 0.01 1.7-2.3 29.0-32.0 1.5-2.5 0.03S 0.06C
*Special limits apply when the product is to be welded and is so specified by the purchaser: 0.5% Zn, 0.02%P, 0.02%Pb, 0.02%S and 0.05%C
Table 4. Typical Physical Properties.
Units 90-10 70-30 66-30-2-2
Density kg/dm3 8.90 8.95 8.86
Melting Range °C 1100-1145 1170-1240
Specific Heat J/kg °K 377 377 377
Thermal Conductivity W/m°K 50 29 25
Coeff. of Linear Expansion
10-6/°K 17 16 15.5
Electrical Resistivity microhm. cm 19 34 50
Modulus of Elasticity GPa 135 152 156
Modulus of Rigidity GPa 50 56