GRADE PROFILE
Copper-nickel 70/30 — CW354H / CuNi30Mn1Fe
Copper-nickel 70/30 raises nickel to 30–32%. It keeps the antifouling effect of 90/10 while handling higher flow velocities and temperatures. It is the copper-nickel of power station condensers and heavily loaded circuits.
- Copper alloy
- PREN: does not apply to this family
- Cost index 290
- Seamless · Heat exchanger
- Ø 6 to 168 mm
When to choose it
On high-velocity condensers, in warm seawater, in power stations and sugar refineries. This is the case where 90/10 reaches its erosion limit: the higher nickel content strengthens the protective film and raises the admissible velocity threshold.
In sugar refining, the alloy is also valued for its resistance to juices and its conductivity.
When not to choose it
Where 90/10 is sufficient. The cost difference is around 40%, and on a moderate-velocity circuit in temperate water it is not justified.
Where ammonia is present, like every copper alloy: stress corrosion cracking is rapid and gives no warning.
In waters polluted by sulphides, which attack the protective film of both copper-nickels.
Composition
| Element | % |
|---|---|
| Cu | ≥ 65 |
| Ni | 30–32 |
| Fe | 0.4–1 |
| Mn | 0.5–1.5 |
Mechanical properties
We only publish mechanical properties tied to a specific standard and product form — welded tube, seamless tube and bar do not share the same values, and the gap routinely exceeds 30%. The figures that apply to your specification appear on the material certificate; ask us at enquiry stage.
Designations and standards
| Reference | Designation |
|---|---|
| EN (numeric) | CW354H |
| EN (symbolic) | CuNi30Mn1Fe |
| ASTM / AISI | 70/30 |
| UNS | C71500 |
| JIS | — |
| AFNOR | — |
Tube product standards :
- EN 12451
- ASTM B111
- ASTM B466
Availability
Available in seamless and heat exchanger tube, Ø 6 to 168 mm, to EN 12451, ASTM B111 and B466. ⚠️ This grade is not offered in welded tube. Partner stock or mill depending on the size and quantity. EN 10204 3.1 material certificates supplied with the goods.
Related grades
- CuNi 90/10 (CW352H) — less nickel, cheaper, below 2.5 m/s.
- Titanium grade 2 (3.7035) — no velocity or chloride limit, but no antifouling.
- 2507 (1.4410) — the duplex route for seawater, with far higher mechanical strength.
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Frequently asked questions
- What is the real gain on flow velocity?
- The admissible threshold is appreciably higher than with 90/10, but it depends on geometry, temperature and water quality. On a condenser project it is validated case by case rather than from a catalogue figure.
- Why are copper-nickels not offered in welded tube?
- Condenser tube in copper alloys is produced seamless, which is what the practice of EN 12451 and ASTM B111 reflects. For a particular requirement, ask us.
- Is ammonia really a deal-breaker?
- Yes. It causes stress corrosion cracking in copper alloys, even at low concentration and ambient temperature. On a circuit that might contain it, even accidentally, copper must be ruled out.