Cu-Ni 70/30 Tube Specifications

The table below shows all the technical details for Cu-Ni 70/30 tubes, so engineers, buyers, and project managers can see if the material is right for their needs.

Parameter Details
Standard ASTM B111 (Seamless) / ASTM B466 (Seamless) / ASTM B543 (Welded)
Outer Diameter Range 6.35 mm to 50.8 mm (1/4" to 4")
Wall Thickness 0.71 mm to 3.05 mm
Length Random, Fixed, or Cut to Length (up to 6000 mm)
Form Seamless Tube, Welded Tube, ERW Tube
Surface Finish Bright Annealed, Pickled, Mill Finish
Condition Annealed / Light Drawn
End Type Plain End, Bevelled End, Threaded End

Cu-Ni 70/30 Tube Sizes and Dimensions

Cu-Ni 70/30 tubes are stocked in a range of standard sizes. The table below summarises available dimensions for both seamless and welded forms.

Dimension Range
Outer Diameter (OD) 6.35 mm (1/4 in.) to 50.8 mm (2 in.)
Wall Thickness 0.71 mm (0.028 in.) to 3.05 mm (0.120 in.)
Standard Length 6 m and 12 m
Seamless Tube OD 9.50 to 24.4 mm
Welded Tube OD 3.18 mm (0.125 in.) to 25.4 mm (1 in.)

Custom lengths, non-standard OD ranges, and special wall thicknesses are available on request with confirmed lead times.

Cu-Ni 70/30 Tube Price

Cu-Ni 70/30 tube prices in India begin at around ₹880 per kg, while international and US prices generally range from about $12 to $30 per kg. The final cost is influenced by multiple parameters, including tube outer diameter, wall thickness, length, order volume, manufacturing type (seamless or welded), relevant specifications (ASTM B111, B466, or B543), and current copper–nickel market conditions. Overseas pricing also shifts based on destination, shipping terms, and the prevailing LME prices for copper and nickel.

Please reach out to our sales team for updated pricing tailored to your exact size and quantity requirements.

Chemical Composition of Cu-Ni 70/30 Tube

The table below lists the nominal composition per ASTM B111 / B466 for Cu-Ni 70/30 tube (UNS C71500). It has a copper-nickel base with minor alloying elements that improve strength and corrosion performance in marine environments.

Copper Cu
Remainder
Nickel Ni
29.0 – 33.0%
Iron Fe
0.40 – 1.0%
Manganese Mn
Max 1.0%
Lead Pb
Max 0.05%
Zinc Zn
Max 1.0%

Mechanical Properties of Cu-Ni 70/30 Tube

The values below apply to standard condenser and seamless tube forms per ASTM B111 and ASTM B466. Cu-Ni 70/30 tubes in the annealed temper (O61) deliver a solid balance of ductility and tensile performance.

360
MPa
Tensile Strength
125
MPa (min)
Yield Strength
30%
(min)
Elongation
80 - 120
HB
Hardness
Property Value
Tensile Strength (Ultimate) 360 MPa
Yield Strength (0.5% Extension) 125 min MPa
Elongation (in 50 mm) 30 min %
Hardness 80 - 120 HB
Density 8.94 g/cm3
Melting Point 1,171°C
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Cu-Ni 70/30 Tube Equivalent Designations

The table below lists the equivalent names and grades for Cu-Ni 70/30 tubes in major international standards. This makes it easier to compare materials and pick the best one for your project.

Standard Designation
UNS C71500
W.Nr. (EN) 2.0882
EN / DIN CuNi30Mn1Fe
ISO CuNi30
BS CN107
JIS C7150
GOST (Russia) MNZhMts 30-1-1

Cu-Ni 70/30 Tube Forms

Copper Nickel 70/30 tubes are produced in 3 primary forms. Each form is governed by a separate ASTM/ASME specification and suits a different service requirement.

  • Seamless Cu-Ni 70/30 Tube
  • Welded Cu-Ni 70/30 Tube
  • Condenser and U-Bend Tubes

Cu-Ni 70/30 Tube Industrial Applications

70/30 copper-nickel tubes are used in many industries because they resist corrosion and biofouling and stay strong even in harsh conditions.The following industries commonly use Cu-Ni 70/30 tubes.

Marine and Offshore

Cu-Ni 70/30 tubes are used for seawater cooling systems, ballast water piping and fire main lines on vessels. The alloy handles seawater without significant erosion-corrosion, which is why it's preferred for high-flow shipboard systems.

Power Generation

Cupronickel 70/30 tubes are used in coastal power plants for condensers and heaters. With seawater as the coolant, C71500 tubes last long and reduce fouling-related shutdowns.

Chemical Processing

UNS C71500 tubes resist weak acids and neutral salt solutions. Chemical plants use them in heat exchangers and cooling lines when fluids or cooling water contain chlorides or other corrosive chemicals.

Oil and Gas

Offshore platforms rely on Cu-Ni 70/30 tubes for fire water systems, seawater lift lines, and hydraulic control tubing. Their proven performance in splash and underwater areas makes them reliable for critical safety systems.

Cu-Ni 70/30 Tube vs Cu-Ni 90/10 Tube

The table below outlines the primary distinctions between Cu-Ni 70/30 (C71500) and Cu-Ni 90/10 Tube (C70600).

Cu-Ni 70/30 is the robust choice, offering superior strength and corrosion resistance, making it ideal for situations with high flow rates or exposure to chlorides. Cu-Ni 90/10 is usually the cheaper choice for standard seawater use, where conditions are not very harsh.

Property Cu-Ni 70/30 (C71500) Cu-Ni 90/10 (C70600)
Nickel Content 29.0 - 33.0% 9.0 - 11.0%
Tensile Strength (Annealed) 372 - 517 MPa 275 - 415 MPa
Max Seawater Flow Velocity 4.5 m/s 3.0 m/s
Corrosion Resistance Higher Moderate
Relative Cost Higher Lower
Primary Use Demanding marine, offshore and naval General seawater cooling, piping

Shipping & Packaging

Main export packaging setup Heavy-duty wooden boxes Packing
Export Packaging Standard

We strictly follow seaworthy export handling standards to protect Cu-Ni 70/30 tubes from transit damage, moisture ingress, and surface contamination during long-distance dispatch.

  • Heavy-duty wooden boxes with moisture barrier lining
  • HDPE stretch film wrapping on all bundles
  • Plastic end caps on threaded and plain-end pipes
  • Silica gel desiccants to minimize moisture exposure
  • ISPM-15 fumigated wooden packaging for export
shipping preparation Tube Bundle Yard Staging
Shipping packaging Container End-Cap Protection
Shipping stock Wrapped Export-Ready Bundles

We Export Worldwide

Sachiya Steel International supplies copper nickel products to major industrial markets across North America, Europe, the Middle East, Asia and Africa with export-ready documentation and logistics support.

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Frequently Asked Questions:

What is Cu-Ni 70/30 tube material? +
Cu-Ni 70/30 tube material is a cupronickel alloy containing approximately 70% copper and 30% nickel (UNS C71500). Iron and manganese are added in small quantities to improve erosion resistance in seawater. The alloy is essentially non-magnetic in annealed condition
What standards cover Cu-Ni 70/30 tubes? +
Cu-Ni 70/30 tubes are covered by ASTM B111 / ASME SB111 (condenser tubes), ASTM B466 / ASME SB466 (seamless pipe and tube), ASTM B543 / ASME SB543 (welded tubes), ASTM B395 / ASME SB395 (U-bend tubes) and ASTM B359 / ASME SB359 (finned tubes).
What sizes are Cu-Ni 70/30 tubes available in? +
Cu-Ni 70/30 tubes are available in OD ranges from 6.35 mm (1/4 in.) to 50.8 mm (2 in.), with wall thickness from 0.71 mm to 3.05 mm. Length is available to 6000 mm. Custom sizes can be produced on request.
What is the difference between Cu-Ni 70/30 and Cu-Ni 90/10 tubes? +
Cu-Ni 70/30 (C71500) contains roughly three times more nickel than Cu-Ni 90/10 (C70600). The higher nickel content gives 70/30 superior corrosion resistance and allows it to handle seawater flow velocities up to 4.5 m/s, compared to 3.0 m/s for the 90/10 grade.
What are Cu-Ni 70/30 tubes used for? +
Cu-Ni 70/30 tubes are used in seawater piping, heat exchangers, steam condensers, desalination plants, offshore fire water systems and chemical process cooling circuits. Marine and offshore sectors are the largest consumers of this alloy grade.
Can Cu-Ni 70/30 tubes be welded? +
Cu-Ni 70/30 tubes can be welded using gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW). Soldering and brazing are also suitable for this alloy. Pre-heat is not required, though joint cleanliness is critical to prevent porosity.
What is the maximum seawater flow velocity for Cu-Ni 70/30 tubes? +
Cu-Ni 70/30 tubes handle seawater flow velocities up to 4.5 m/s without significant erosion-corrosion. This is higher than the 3.0 m/s limit for Cu-Ni 90/10, making the 70/30 grade preferable for high-velocity cooling water systems.
What is the price of Cu-Ni 70/30 tubes? +
Cu-Ni 70/30 tube prices in India start at about Rs 880 per kg, while in the US they are roughly $12 to $30 per kg, depending on size, length, order quantity, tube type, and current copper-nickel prices.

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