Top Cupronickel Pipes and Fittings Manufacturer & Exporter

Corrosion Behaviour

Our CuNi 70/30 and CuNi 10/90 products have excellent behavior when exposed to all forms of marine corrosion.

This property is mainly due to the fact that the alloy prevents dissolution by forming a very strong protective surface film.

Possible Factors of Corrosion

Corrosive environment Probable corrosion Behavior in service
Clean sea water
circulation at a velocity
of up to 1 m/s
Uniform or general 0,0025 - 0,025 mm/an
Clean sea water
circulation at a velocity
of up to 3,5 m/s* :
and 4,5 m/s* :
Impact corrosion Satisfactory
Polluted sea water and accelerated
pitting corrosion
General corrosion Less resistance
Deposits accumulated at the surface Local attack Generally good
Corrosion + stress Stress corrosion Very resistant

* the local speeds resulting from obstructions can be higher.

Behaviour of Our Products in the Presence of Sea Water, Brine and Sea Atmospheric Exposures.

Type of corrosion Behaviour
General corrosion Slightly sensitive to this type of corrosion
Corrosion rate is less than 25 μ/year
Pitting corrosion Insensitive to this type of attack
Penetration rate less than 25/130 μ/year
Selective corrosion Insensitive
Do not lose the alloying component like brasses and aluminium bronzes
Stress corrosion Never affected by this type of corrosion
Fouling corrosion Insensitive
Even at a low circulation speed, and although not affected by general corrosion, perfectly resist to the build-up of marine organisms
(impingement attack)
Very slightly sensitive
The addition of an optimum quantity of iron improves the nature of the protective film and makes the alloy very resistant to this type of agression
Galvanic corrosion Insensitive in the presence of other copper based metals.
With a dissolution potential of 200 mv/ECS in sea water,
is compatible with all other copper based metals.

Behaviour of Our Products in Other Environments

  • good resistance in an ammoniacal environment
  • the behaviour of copper nickel in the presence of crude petroleum is correct in the vapour phase, with however, the risk of the protective film being destroyed.

Resistance of to Fire

Tests of resistance to fire have been made in simulating the service conditions of a pipeline during an offshore fire : piping empty – during 5 minutes – at 700°C, partly in the flame, then 15 minutes on water (with the start of the sprinklers).

They have shown the total reliability of : no rupture of the weld or of the brazing, no leakage, no permanent deformation. After the end of the fire, the piping in has needed no replacement.