90/10 copper-nickel C70600 – UNS C70600
Copper-nickel alloy with iron for seawater
Alloy with ≈ 10% Ni, 1 – 1.8% Fe and up to 1% Mn, the reference for piping and heat exchangers working with seawater. Resists erosion-corrosion, stress corrosion cracking and biofouling, at a lower cost than 70/30. Good ductility and weldability.
Designations and equivalents
| System | Designation |
|---|---|
| UNS | C70600 |
| W.Nr./EN | CW352H – CuNi10Fe1Mn |
| DIN | 2.0872 (CuNi10Fe1Mn) |
| JIS | C7060* |
| Trade names | 90/10 copper-nickel, CuNi 90/10 |
| Others | MIL-T-16420, MIL-T-15005 (tube); MIL-C-15726; SAE J461/J463 |
Standards by product form
| Form | Standard |
|---|---|
| Tube | ASTM B111/B111M (condenser), B466 (seamless), B467 (welded), B543, B552 |
| Plate | ASTM B122/B122M; B171/B171M (tubesheets) |
| Bar | ASTM B151/B151M |
| Tube | EN 12449, EN 12451* |
Tolerances and HS codes
- Forged bars (round and square): machining allowance from 2 mm (Ø 6–16 mm) to 24 mm (Ø 400–500 mm) on the diameter. E.g. Ø 100–125 mm finished: +7 mm, tolerance +6 / −0 (length up to 3,500 mm).
- Forged discs: allowance of 4 to 9 mm on the diameter and 3 to 11 mm on the height, plus-only tolerance.
- Cutting and machining: band saw −0 / +5 to +15 mm on length; waterjet +10 % of thickness on the diameter (min. 2 mm); machined parts −0 / +2 to +5 mm on the diameter. See the full tables (INF 002 and INF 003, the same for every alloy).
| Form | NCM (Brazil, 8 digits) | HS (international, 6 digits) | HTS (USA, 10 digits)* | CN (European Union, 8 digits)* |
|---|---|---|---|---|
| Forged bar | 7407.29.10 | 7407.29 | 7407.29.4000 | 7407 29 00 |
| Hot-rolled bar | 7407.29.10 | 7407.29 | 7407.29.4000 | 7407 29 00 |
| Plate (> 10 mm, width ≥ 600 mm) | 7409.40.90 | 7409.40 | 7409.40.0000 | 7409 40 00 |
| Seamless pipe | 7411.22.10 | 7411.22 | 7411.22.0000 | 7411 22 00 |
| Welded pipe | 7411.22.10 | 7411.22 | 7411.22.0000 | 7411 22 00 |
Tariff class: copper-nickel alloy (cupronickel) (by chemical composition, under the Chapter 72 Notes and Section XV Note 5).
*: US and EU codes for reference. NCM per current legislation (General Rules of Interpretation, Notes to Chapters 72, 74 and 75 and Section XV Note 5). Confirm the final code with your customs broker according to the item size and finish. HS = first 6 digits of the NCM.
Chemical composition (%)
ASTM B111 / B466 (UNS C70600)
| Element | Range (%) |
|---|---|
| Ni (+Co) | 9.0 – 11.0 |
| Fe | 1.0 – 1.8 |
| Mn | ≤ 1.0 |
| Zn | ≤ 1.0 |
| Pb | ≤ 0.05 |
| Cu | balance (Cu + named elements ≥ 99.5) |
Mechanical properties
typical, annealed tube (O61, CDA)
| Property | Value |
|---|---|
| Tensile strength | ≈ 303 MPa |
| Yield strength (0.5%) | ≈ 110 MPa |
| Elongation | ≈ 42% |
| Hardness | ≈ 15 HRB (≈ 65 HRF) |
| Light-drawn tube (H55): tensile strength | ≥ 310 MPa |
Typical physical properties
| Property | Value |
|---|---|
| Density | 8.94 g/cm³ |
| Melting range | 1,099 – 1,149 °C |
| Modulus of elasticity | 124 GPa |
| Electrical conductivity | ≈ 9% IACS |
| Thermal conductivity (20 °C) | ≈ 45 W/m·K |
| Thermal expansion (20–300 °C) | 17.1 µm/m·K |
Heat treatment, welding and machining
| Item | Usual practice |
|---|---|
| Service temperature | Usual from sub-zero temperatures up to ≈ 300 °C*. In seawater, typical design velocity up to ≈ 3.5 m/s in tubes*; above that, prefer 70/30. |
| Heat treatment | Annealing at ≈ 595 – 815 °C. Hot working between ≈ 845 and 955 °C. Not hardenable by heat treatment, only by cold work. |
| Welding | Excellent by TIG/MIG and butt welding; good by covered electrode. 70/30 consumables: AWS A5.7 ERCuNi and A5.6 ECuNi. Excellent brazing and soft soldering. |
| Machining | Ductile, gummy material (≈ 20, C36000 = 100). Sharp tool, positive rake and coolant. |
Typical applications
- Condenser and heat exchanger tubes cooled with seawater
- Seawater piping and firewater systems on ships and platforms
- Desalination plants
- Antifouling cladding of offshore structures
- Automotive brake and hydraulic lines
Alternatives: 70/30 copper-nickel C71500 for higher flow velocity, polluted water or higher pressure; Monel 400 for more severe service; naval brass C46400 for tubesheets and lower-cost structural parts.
Frequently asked questions
What is the chemical composition of 90/10 copper-nickel C70600?
Per ASTM B111 / B466 (UNS C70600): Ni (+Co) 9.0 – 11.0; Fe 1.0 – 1.8; Mn ≤ 1.0; Zn ≤ 1.0; Pb ≤ 0.05; Cu balance (Cu + named elements ≥ 99.5).
Which standards cover 90/10 copper-nickel C70600?
Tube: ASTM B111/B111M (condenser), B466 (seamless), B467 (welded), B543, B552. Plate: ASTM B122/B122M; B171/B171M (tubesheets). Bar: ASTM B151/B151M. Tube: EN 12449, EN 12451*.
Up to what temperature can 90/10 copper-nickel C70600 be used?
Usual from sub-zero temperatures up to ≈ 300 °C*. In seawater, typical design velocity up to ≈ 3.5 m/s in tubes*; above that, prefer 70/30.
Which materials can replace 90/10 copper-nickel C70600?
70/30 copper-nickel C71500 for higher flow velocity, polluted water or higher pressure; Monel 400 for more severe service; naval brass C46400 for tubesheets and lower-cost structural parts.
