Why does PREN not apply?

Because it is a formula built on the chromium, molybdenum and nitrogen of stainless steels. A copper-nickel alloy contains none of these as alloying elements: the value does not exist, and inventing one would be misleading.

What is the antifouling effect?

Copper releases very small quantities of ions that prevent marine organisms from settling on the wall. A copper-nickel tube stays clean where a stainless or titanium tube is colonised and loses heat transfer efficiency.

90/10 below 2.5 m/s and in temperate seawater — cheaper. 70/30 as soon as velocity rises, the water is warm, or service is continuous at high load.

GRADE PROFILE

Copper-nickel 90/10 — CW352H / CuNi10Fe1Mn

Copper-nickel 90/10 combines at least 86% copper with 9 to 11% nickel and 1 to 2% iron. Its distinguishing feature comes down to one word: antifouling. Copper naturally prevents marine organisms from settling, which neither stainless nor titanium does.

Copper alloy
PREN: does not apply to this family
Cost index 210
Seamless · Heat exchanger
Ø 6 to 168 mm

When to choose it

On seawater condensers, marine cooling circuits, in desalination. Copper-nickel is the historic material of these circuits, and its antifouling property is an operating argument as much as a corrosion one: a condenser that does not foul keeps its efficiency and avoids cleaning shutdowns.

Its thermal conductivity, far higher than that of stainless, also improves exchanger performance directly.

When not to choose it

Above roughly 2.5 m/s flow velocity. The protective film is eroded by the fluid and erosion-corrosion starts, often at tube inlets. That is the governing limit of 90/10: if velocity has to rise, move to 70/30.

In waters polluted by sulphides, which destroy the protective film.

Where ammonia is present, which causes stress corrosion cracking in copper alloys.

Composition

Chemical composition (% by mass)
Element	%
Cu	≥ 86
Ni	9–11
Fe	1–2
Mn	0.5–1

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

Equivalent normative designations
Reference	Designation
EN (numeric)	CW352H
EN (symbolic)	CuNi10Fe1Mn
ASTM / AISI	90/10
UNS	C70600
JIS	—
AFNOR	—

Tube product standards :

EN 12451
EN 12449
ASTM B111
ASTM B466

Availability

Available in seamless and heat exchanger tube, Ø 6 to 168 mm, to EN 12451, EN 12449, 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 70/30 (CW354H) — more nickel, for high velocities and warm seawater.
Titanium grade 2 (3.7035) — indifferent to chlorides and without a velocity limit, but with no antifouling.
254 SMO (1.4547) — the stainless route for seawater.

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Frequently asked questions

Why does PREN not apply?: Because it is a formula built on the chromium, molybdenum and nitrogen of stainless steels. A copper-nickel alloy contains none of these as alloying elements: the value does not exist, and inventing one would be misleading.
What is the antifouling effect?: Copper releases very small quantities of ions that prevent marine organisms from settling on the wall. A copper-nickel tube stays clean where a stainless or titanium tube is colonised and loses heat transfer efficiency.
90/10 or 70/30?: 90/10 below 2.5 m/s and in temperate seawater — cheaper. 70/30 as soon as velocity rises, the water is warm, or service is continuous at high load.