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UNS C18600 Chromium Copper

C18600 copper is a lightly alloyed grade of copper, formulated for primary forming into wrought products. It has a moderately high embodied energy among wrought coppers. In addition, it can have a moderately high tensile strength and a moderately low ductility.

The properties of C18600 copper include two common variations. This page shows summary ranges across both of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C18600 copper to: wrought coppers (top), all copper alloys (middle), and the entire database (bottom). A full bar means this is the highest value in the relevant set. A half-full bar means it's 50% of the highest, and so on.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

120 GPa 17 x 106 psi

Elongation at Break

8.0 to 11 %

Poisson's Ratio


Shear Modulus

44 GPa 6.3 x 106 psi

Shear Strength

310 to 340 MPa 45 to 49 x 103 psi

Tensile Strength: Ultimate (UTS)

520 to 580 MPa 76 to 84 x 103 psi

Tensile Strength: Yield (Proof)

500 to 520 MPa 72 to 76 x 103 psi

Thermal Properties

Latent Heat of Fusion

210 J/g

Maximum Temperature: Mechanical

200 °C 390 °F

Melting Completion (Liquidus)

1090 °C 2000 °F

Melting Onset (Solidus)

1070 °C 1960 °F

Specific Heat Capacity

390 J/kg-K 0.092 BTU/lb-°F

Thermal Conductivity

280 W/m-K 160 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

70 % IACS

Electrical Conductivity: Equal Weight (Specific)

71 % IACS

Otherwise Unclassified Properties

Base Metal Price

31 % relative


8.9 g/cm3 560 lb/ft3

Embodied Carbon

2.9 kg CO2/kg material

Embodied Energy

46 MJ/kg 20 x 103 BTU/lb

Embodied Water

310 L/kg 37 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

44 to 58 MJ/m3

Resilience: Unit (Modulus of Resilience)

1060 to 1180 kJ/m3

Stiffness to Weight: Axial

7.3 points

Stiffness to Weight: Bending

18 points

Strength to Weight: Axial

16 to 18 points

Strength to Weight: Bending

16 to 17 points

Thermal Diffusivity

81 mm2/s

Thermal Shock Resistance

19 to 20 points

Alloy Composition

Among wrought copper alloys, the composition of C18600 copper is notable for including zirconium (Zr) and chromium (Cr). Zirconium is used to increase recrystallization temperature and to permit or facilitate certain forms of heat treatment. Chromium additions permits certain types of heat treatment to improve mechanical strength.

Copper (Cu)Cu 96.5 to 99.55
Chromium (Cr)Cr 0.1 to 1.0
Iron (Fe)Fe 0.25 to 0.8
Titanium (Ti)Ti 0.050 to 0.5
Zirconium (Zr)Zr 0.050 to 0.4
Nickel (Ni)Ni 0 to 0.25
Cobalt (Co)Co 0 to 0.1
Residualsres. 0 to 0.5

All values are % weight. Ranges represent what is permitted under applicable standards.

Followup Questions

Similar Alloys

Further Reading

Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993