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UNS C12900 Fire-Refined Silver-Bearing Tough Pitch Copper

C12900 copper is a lightly alloyed grade of copper, formulated for primary forming into wrought products.

The properties of C12900 copper include nine common variations. This page shows summary ranges across all of them. For more specific values, follow the links immediately below. The graph bars on the material properties cards further below compare C12900 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

2.8 to 50 %

Poisson's Ratio


Rockwell F Hardness

40 to 95

Shear Modulus

43 GPa 6.3 x 106 psi

Shear Strength

150 to 210 MPa 22 to 31 x 103 psi

Tensile Strength: Ultimate (UTS)

220 to 420 MPa 32 to 61 x 103 psi

Tensile Strength: Yield (Proof)

75 to 380 MPa 11 to 56 x 103 psi

Thermal Properties

Latent Heat of Fusion

210 J/g

Maximum Temperature: Mechanical

200 °C 390 °F

Melting Completion (Liquidus)

1080 °C 1980 °F

Melting Onset (Solidus)

1030 °C 1880 °F

Specific Heat Capacity

390 J/kg-K 0.092 BTU/lb-°F

Thermal Conductivity

380 W/m-K 220 BTU/h-ft-°F

Thermal Expansion

17 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

98 % IACS

Electrical Conductivity: Equal Weight (Specific)

98 % IACS

Otherwise Unclassified Properties

Base Metal Price

32 % relative


9.0 g/cm3 560 lb/ft3

Embodied Carbon

2.6 kg CO2/kg material

Embodied Energy

41 MJ/kg 18 x 103 BTU/lb

Embodied Water

330 L/kg 39 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

11 to 88 MJ/m3

Resilience: Unit (Modulus of Resilience)

24 to 640 kJ/m3

Stiffness to Weight: Axial

7.2 points

Stiffness to Weight: Bending

18 points

Strength to Weight: Axial

6.8 to 13 points

Strength to Weight: Bending

9.1 to 14 points

Thermal Diffusivity

110 mm2/s

Thermal Shock Resistance

7.8 to 15 points

Alloy Composition

Among wrought copper alloys, the composition of C12900 copper is notable for including bismuth (Bi) and tellurium (Te). Bismuth improves machinability. It is used a non-toxic but more expensive replacement for lead. Tellurium is used to improve machinability.

Copper (Cu)Cu 99.88 to 100
Silver (Ag)Ag 0 to 0.054
Nickel (Ni)Ni 0 to 0.050
Tellurium (Te)Te 0 to 0.025
Arsenic (As)As 0 to 0.012
Lead (Pb)Pb 0 to 0.0040
Bismuth (Bi)Bi 0 to 0.0030
Antimony (Sb)Sb 0 to 0.0030

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

Followup Questions

Similar Alloys

Further Reading

CRC Materials Science and Engineering Handbook, 4th ed., James F. Shackelford et al. (editors), 2015