70/30 UNS C71500 copper nickel alloys Tubes

Copper nickel alloys comprise 2 to 30% nickel and have high oxidation resistance and stress corrosion cracking resistance. Their high oxidation resistance is seen in moist air and steam. These alloys are thermally stable and possess moderate strength even when the temperature is high. The corrosion resistance and strength of these alloys are improved by the addition of manganese, iron, niobium, and or chromium. Copper nickel alloys also have good fabricability and high inherent resistance to biofouling.

The soluble nature of nickel in copper provides the copper nickel alloys with single phase alpha structures. The alpha dendrites in the cast structures contain a large amount of nickel starting from the center up to the edge of the dendrite. A large quantity of nickel is also present in interdendritic regions. The dendrite structure is broken by mechanical treatments. The alloying elements do not get homogenized even by repeated thermal and mechanical treatments.

Copper nickel alloys are of two types that include 70/30 and 90/10. The 70/30 copper nickel alloys have great resistance to sea water-related corrosion due to the presence of significant amounts of manganese and iron.

Copper nickel alloys are used in the following areas:

• Desalination units
• Hydraulic lines
• Fish cages for aquaculture
• Heat exchangers and condensers
• Nickel Alloy Pipes for sea water pipework
• Offshore fire water systems
• Tubes for power plants and ships
• Pumps, valves, sheathing and fittings for ship hulls

Chemical Composition

The chemical composition of UNS C71500 copper nickel alloys Tubes are outlined in the following table.

Element	Content (%)
Copper, Cu	70.0
Nickel, Ni	30.0

Physical Properties

The following table shows the physical properties of UNS C71500 copper nickel alloys Tube.

Properties	Metric	Imperial
Density	8.94 g/cm3	0.323 lb/in3
Melting point	2140°F	1171°C

Mechanical Properties

The mechanical properties of UNS C71500 copper nickel alloys Tubes are displayed in the following table.

Properties	Metric	Imperial
Tensile strength, ultimate	372-517 MPa	54000-75000 psi
Tensile strength, yield (depending on temper)	88.0-483 MPa	12800-70100 psi
Elongation at break (in 381 mm)	45.0%	45.0%
Charpy impact	107 J	78.9 ft-lb
Machinability (UNS C36000 (free-cutting brass) = 100%)	20%	20%
Shear modulus	57.0 GPa	8270 ksi
Poisson's ratio	0.34	0.34
Elastic modulus	150 GPa	21800 ksi

Other Designations

Equivalent materials to UNS C71500 copper nickel alloys Tubes are:

ASME SB111	ASME SB171	ASME SB359	ASME SB395
ASME SB466	ASME SB467	ASME SB543	ASTM B111
ASTM B122	ASTM B151	ASTM B171	ASTM B359
ASTM B395	ASTM B432	ASTM B466	ASTM B543
ASTM B552	ASTM B552	ASTM B608	ASTM F467
ASTM F468	DIN 2.0882	MIL C-15726	MIL T-15005
MIL T-16420	MIL T-22214	SAE J461	SAE J463

Fabrication and Heat Treatment

Annealing

UNS C71500 copper nickel alloys Tubes are annealed at temperatures between 649 and 816°C (1200 and 1500°F)

Cold Working

UNS C71500 copper nickel alloys Tubes have good cold working capacity.

Hot Working

UNS C71500 Copper nickel 70/30 alloys Tubes are hot formed in an excellent manner.

Welding

UNS C71500 Copper nickel 70/30 alloys Tubes can be welded using gas shielded arc welding, spot welding, coated metal arc welding, butt welding, seam welding, brazing, soldering and oxyacetylene welding processes.

Forging

Temperatures between 927 and 1038°C (1700 and 1900°F) are suitable for the copper nickel 70/30 alloys Tubes.

Machinability

The machinability rating of copper nickel 70/30 alloys Tubes is 20%.

Applications

UNS C71500 copper nickel alloys Tubes are used in areas where stainless steel cannot be used due to chloride stress-corrosion cracking and in other parts requiring high corrosion resistance. These alloys are also used as machined and forged valve and pump parts that are utilized for seawater services.

For more information on this source, please visit Yaang Pipe Industry.

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