OSNA®-10 and OSNA®-30                                                                                    

The sea and its atmosphere is one of the most corrosive environments on the earth. Seagoing vessels need large amounts of seawater daily for:

> fire water systems
> sprinkler systems
> cooling systems
> ballast systems

The materials used for seawater piping systems therefore must be highly resistant to cavitation erosion, crevice and galvanic corrosion as well as stress corrosion cracking. Moreover such materials must satisfy high standards in terms of hot and cold working properties and weldability

THE MATERIAL Main properties and advantages of copper nickel alloy

For decades, seawater pipe systems made of copper-nickel alloys have been put to successful use on seagoing vessels and offshore production units like platforms, drilling rigs, semi-submersibles FPSOs etc. The chemical composition of OSNA®-10 (CuNi 90/10) and OSNA®-30 (CuNi 70/30) copper nickel alloys have been modified so that they meet the requirements of all the main international standards (see tables below). Reduced tolerance limits for certain impurities moreover provide for an enhanced cold workability and weldability of cunova’s alloy. OSNA®-10 and OSNA®-30 seawater pipes are manufactured in two configurations: seamless and seam welded.

Main Advantages of OSNA®10 and OSNA®-30

Despite the rough conditions in marine service and the highly corrosive nature of seawater, the products provide well balanced combination of technical and economical advantages:

> Simple alloying system with good weldability

> Excellent ductility and toughness

> Outstanding erosion corrosion performance

> Resistant to uniform and localized corrosion

> No effect of ambient seawater temperatures

> No effect of seawater chlorination

> Resistant to biofouling

> Resistant to stress-corrosion cracking

> Low maintenance costs

> A lot of design experience