Copper nickel alloys are alloys that have moderate strength and thermal stability in high temperature levels. The high oxidation resistance of these alloys is visible in moist air and steam. Copper nickel alloys have 2 to 30% nickel, high oxidation resistance and stress corrosion cracking resistance.
Copper nickel alloys have good fabricability and high inherent resistance to biofouling. The addition of manganese, niobium, iron and or chromium in these alloys improves their corrosion resistance and strength.
Nickel is soluble in copper and this renders the copper nickel alloys as single phase alpha structures. The cast structures have alpha dendrites that contain huge quantities of nickel. The dendrite structure is broken by mechanical treatments. However, the alloying elements do not become homogenized even by repeated thermal and mechanical treatments.
Copper nickel alloys are of two types that include 90/10 and 70/30. The 90/10 alloys are widely used as they are inexpensive. The 90/10 copper nickel alloys have great resistance to sea water corrosion due to the presence of significant amounts of manganese and iron.
Copper nickel alloys are used in the following applications:
Hydraulic lines
Fish cages for aquaculture
Heat exchangers and condensers
Desalination units
Sea water pipework
Tubes for power plants and ships
Offshore fire water systems
Pumps, valves, sheathing and fittings for ship hulls
The following datasheet will provide details about UNS C70600 copper nickel alloys.
Chemical Composition
The chemical composition of UNS C70600 copper nickel alloys is outlined in the following table.ElementContent (%)Cu88.7Fe1.3Ni10.0
Physical Properties
The following table shows the physical properties of UNS C70600 copper nickel alloys.PropertiesMetricImperialDensity8.94 g/cm30.323 lb/in3
Mechanical Properties
The mechanical properties of UNS C70600 copper nickel alloys are displayed in the following table.PropertiesMetricImperialTensile strength, ultimate303-414 MPa43900-60000 psiTensile strength, yield (depending on temper)110-393 MPa16000-57000 psiElongation at break (in 254 mm)42.00%42.00%Machinability (UNS C36000 (free-cutting brass) = 100%)20%20%Shear modulus52.0 GPa7540 ksiPoisson’s ratio0.340.34Elastic modulus140 GPa20300 ksi
Other Designations
Equivalent materials to UNS C70600 copper nickel alloys are:ASME SB111ASTM B111ASTM B466ASME SB171ASME SB359ASTM B122ASTM B469MIL T-22214ASME SB395ASTM B151ASTM B543SAE J461ASME SB466ASTM B171ASTM B608SAE J463ASME SB467ASTM B359DIN 2.0872MIL T-16420ASME SB543ASTM B395MIL C-15726MIL T-15005ASTM B432
Fabrication and Heat Treatment
Annealing
UNS C70600 copper nickel alloys are annealed at temperatures between 593 and 816°C (1100 and 1500°F)
Cold Working
UNS C70600 copper nickel alloys have good cold working capacity.
Hot Working
Copper nickel 90/10 alloys have good hot forming capacity.
Welding
Copper nickel 90/10 alloys can be welded using gas shielded arc welding, spot welding, coated metal arc welding, butt welding, oxyacetylene welding, brazing, soldering and seam welding processes.
Forging
Temperatures between 843 and 954°C (1550 and 1750°F) are suitable for the forging of 90/10 copper nickel alloys.
Machinability
The machinability rating of copper nickel 90/10 alloys is 20%.
Applications
UNS C70600 copper nickel alloys are used in areas where stainless steel cannot be used due to chloride stress-corrosion cracking and in other parts requiring high levels of corrosion resistance. These alloys are also used as machined and forged valve and pump parts that are utilized for seawater services.
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