C72900 Introduction

Copper alloys are of many types. The addition of various other elements provides each alloy its distinct characteristics. The addition of nickel to a copper alloy improves strength and corrosion resistance. Copper nickel alloys are also called cupronickel alloys.

The following datasheet discusses the chemical composition and properties of copper UNS C72900.

Other Designations

Equivalent material to UNS C72900 copper alloy is ASTM B740.


  • Welding – Soldering, seam welding, spot welding, butt welding, coated metal arc welding, brazing, gas shielded arc welding are all excellent methods. Oxyacetylene welding can also be used.
  • Forging – The hot forging temperature for copper UNS C72900 alloy ranges between 649 and 871°C (1200 and 1600°F).
  • Hot working – Copper UNS C72900 alloy has good hot working abilities.
  • Cold working – Copper UNS C72900 alloy has excellent cold working properties.
  • Annealing – Copper UNS C72900 alloy is annealed at temperatures 824ºC (1515ºF).


Chemical Composition

The chemical composition of UNS C72900 copper alloy is outlined in the following table.

Min (%)7.514.5
Max (%)Rem0.028.50.500.5015.50.150.300.10
(1) Cu + Sum of Named Elements 99.7% min.
(2) Cu value includes Ag.
(3) 0.005% Pb max. for hot rolling.
(4) Ni value includes Co.

Mechanical Properties *

FormTemperTemper CodeTensile Strength
YS-0.2% Offset
YS-0.5% Ext
YS-0.05% OffsetElongation
Strip1/2 Hard and Spinodal Hardened (1/2 TS)TS02145 Min for Standard125 Min for Standard3 Typ
1/4 Hard and Spinodal Hardened (1/4 TS)TS01130 Min for Standard105 Min for Standard4 Typ
3/4 Hard and Spinodal Hardened (3/4 TS)TS03155 Min for Standard135 Min for Standard2 Typ
Hard and Spinodal HardenedTS04165 Min for Standard145 Min for Standard2 Typ
Mill-hardened Temper, TM – 1/2 HardTM02105 Min for Standard90 Min for Standard80 Min for Standard15 Typ
Mill-hardened Temper, TM – 1/2 HardTM0095 Min for Standard75 Min for Standard70 Min for Standard22 Typ
Mill-hardened Temper, TM – HardTM04115 Min for Standard105 Min for Standard95 Min for Standard10 Typ
Mill-hardened Temper, TM – XHMS SpringTM08150 Min for Standard140 Min for Standard125 Min for Standard2 Typ
Mill-hardened Temper, TM -XHM – Extra HardTM06130 Min for Standard120 Min for Standard105 Min for Standard6 Typ
Solution Heat TreatedTB0064 Min for Standard24 Min for Standard32 Typ
Solution Heat Treated and Cold Worked: 1/2 HardTD0285 Min for Standard8 Typ
Solution Heat Treated and Cold Worked: 1/4 HardTD0175 Min for Standard50 Min for Standard18 Typ
Solution Heat Treated and Cold Worked: 3/4 HardTD0395 Min for Standard80 Min for Standard3 Typ
Solution Heat Treated and Cold Worked: HardTD04100 Min for Standard85 Min for Standard
Spinodal Hardened-Low Strength (ATLS)TX00120 Min for Standard95 Min for Standard6 Typ
* Measured at room temperature, 68°F (20°C).

Physical Properties

Melting Point – Liquidus°F2039
Melting Point – Solidus°F1742
Densitylb/cu in. at 68°F0.323
Specific Gravity8.94
Electrical Conductivity% IACS at 68°F7.8 (1)
Thermal ConductivityBtu/ sq ft/ ft hr/ °F at 68°F17
Coefficient of Thermal Expansion 68-57210 to -6 power per °F (68 – 572°F)9.1
Specific Heat CapacityBtu/ lb /°F at 68°F0.09
Modulus of Elasticity in Tensionksi18500
Modulus of Rigidityksi7500
(1)Aged condition.

Fabrication Properties

Oxyacetylene WeldingGood
Gas Shielded Arc WeldingExcellent
Coated Metal Arc WeldingExcellent
Spot WeldExcellent
Seam WeldExcellent
Butt WeldExcellent
Capacity for Being Cold WorkedExcellent
Capacity for Being Hot FormedGood

Common Fabrication Processes

No fabrication process properties for this alloy

Thermal Properties

Hot Working Temperature12001600
* Temperature is measured in Fahrenheit.

Typical uses

Product CategoryProductReason CategoryReason
ElectricalConnectorsConductivity (Electrical)Electrical Conductivity
ConnectorsConductivity (Thermal)Thermal Conductivity
ConnectorsCorrosion ResistanceCorrosion Resistance
ConnectorsCorrosion ResistanceResistant to Oxidation
ConnectorsForming CharacteristicsFormability
ConnectorsMechanical PropertiesHigh Modulus of Elasticity
ConnectorsMechanical PropertiesVery High Strength
ConnectorsThermal PropertiesResistance to Stress Relaxation
ContactsConductivity (Electrical)Electrical Conductivity
ContactsConductivity (Thermal)Thermal Conductivity
ContactsCorrosion ResistanceCorrosion Resistance
ContactsCorrosion ResistanceCorrosion Resistance to Fresh Water
ContactsCorrosion ResistanceCorrosion Resistance to Salt Water
ContactsCorrosion ResistanceResistant to Oxidation
ContactsForming CharacteristicsFormability
ContactsMechanical PropertiesHigh Modulus of Elasticity
ContactsMechanical PropertiesVery High Strength
ContactsThermal PropertiesResistance to Stress Relaxation
ControlsConductivity (Electrical)Electrical Conductivity
ControlsConductivity (Thermal)Thermal Conductivity
ControlsCorrosion ResistanceCorrosion Resistance
ControlsCorrosion ResistanceCorrosion Resistance to Salt Water
ControlsMechanical PropertiesHigh Strength
Miniaturized SocketsCorrosion ResistanceCorrosion Resistance
Miniaturized SocketsForming CharacteristicsFormability
Miniaturized SocketsMechanical PropertiesHigh Modulus of Elasticity
Miniaturized SocketsMechanical PropertiesVery High Strength
Relay ElementsConductivity (Electrical)Electrical Conductivity
Relay ElementsConductivity (Thermal)Thermal Conductivity
Relay ElementsCorrosion ResistanceCorrosion Resistance
Relay ElementsCorrosion ResistanceResistant to Oxidation
Relay ElementsForming CharacteristicsFormability
Relay ElementsMechanical PropertiesHigh Modulus of Elasticity
Relay ElementsMechanical PropertiesVery High Strength
Relay ElementsThermal PropertiesResistance to Stress Relaxation
SwitchesConductivity (Electrical)Electrical Conductivity
SwitchesConductivity (Thermal)Thermal Conductivity
SwitchesCorrosion ResistanceCorrosion Resistance
SwitchesCorrosion ResistanceCorrosion Resistance to Salt Water
SwitchesMechanical PropertiesHigh Strength
IndustrialSpringsCorrosion ResistanceCorrosion Resistance
SpringsCorrosion ResistanceResistant to Oxidation
SpringsForming CharacteristicsFormability
SpringsMechanical PropertiesHigh Modulus of Elasticity
SpringsMechanical PropertiesVery High Strength
SpringsThermal PropertiesResistance to Stress Relaxation
WireCorrosion ResistanceCorrosion Resistance
WireCorrosion ResistanceResistant to Oxidation
WireForming CharacteristicsFormability
WireMechanical PropertiesHigh Modulus of Elasticity
WireMechanical PropertiesVery High Strength
MarineMarine ComponentsCorrosion ResistanceCorrosion Resistance
Marine ComponentsCorrosion ResistanceCorrosion Resistance to Fresh Water
Marine ComponentsCorrosion ResistanceCorrosion Resistance to Salt Water
Marine ComponentsCorrosion ResistanceResistant to Oxidation
Marine ComponentsForming CharacteristicsFormability
Marine ComponentsMechanical PropertiesHigh Modulus of Elasticity
Marine ComponentsMechanical PropertiesVery High Strength
Marine ComponentsThermal PropertiesResistance to Stress Relaxation

Applicable Specifications

FormSpecific Sub-FormApplicationSystemStandardDescription