Copper Nickel flange Cu-Ni 90/10, Cu-Ni 70/30

Copper Nickel Standards and Composition

Copper Nickel Tube Applications

Cu-Ni alloys are alloys of copper (base metal with the largest individual content) and nickel with or without other elements, whereby the zinc content may not be more than 1%. When other elements are present, nickel has the largest individual content after copper, compared with each other element. As with other copper alloys, it is necessary to distinguish between wrought alloys, which are processed to semi-finished products, and cast alloys, from which castings are produced by various casting processes. The Cu-Ni alloys with additions of manganese are important in electrical engineering. Additions of iron significantly improve the resistance of Cu-Ni alloys to erosion corrosion in flowing seawater and other aggressive waters.
Copper Nickel Applications

Copper alloys have very good resistance to seawater, brine water, organic compounds, salts, diluted non-oxidizing acids, and more. CuNi 90/10 (C70600 & C7060X) is a Copper Nickel Iron alloy with a small content of manganese which allows excellent resistance to sea- and brakish water. Of all commercial coper alloys, CuNi 70/30 (C71500) offers the best resistance to aqueous corrosion. It is resistant to acid solutions and highly resistant to stress corrosion cracking, and impingement corrosion. In addition, CuNi70/30 offers a greater strength for higher pressures.

Cupronickel (copper nickel) is an alloy of copper, nickel and strengthening elements such as iron and manganese. Cupronickel exhibits superior corrosion resistance in seawater. Because of this, it is used for marine hardware, piping systems and sometimes for the propellers, crankshafts and hulls of premium tugboats, fishing boats and other working boats.

The cupronickel alloy technology has been known by the Chinese since the third century BC under the name white copper and was used in corrosive environments. It is still used extensively in modern boat building. Cupronickel is uniquely qualified as an ideal candidate for piping systems in the ship-building industry due to its alloy properties, including low general corrosion rates in seawater, resistance to stress corrosion cracking due to ammonia in seawater, high resistance to crevice corrosion and stress corrosion due to chlorides, good pitting resistance, ready weldability, ease of fabrication and inherent resistance to biofouling. In some cases, cupronickel seawater piping systems can last a ship’s lifetime.