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UNS C17200 (CW101C) Beryllium Copper

C17200 copper is a lightly alloyed grade of copper, formulated for primary forming into wrought products. CW101C is the EN numeric designation for this material. C17200 is the UNS number. Additionally, the EN chemical designation is CuBe2. Older literature may refer to this material as ASTM Alloy 25, but this is now discouraged.

It has a moderately low electrical conductivity among wrought coppers. In addition, it has a moderately low melting temperature and can have a moderately high tensile strength.

The properties of C17200 copper include fifteen 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 C17200 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

1.1 to 37 %

Poisson's Ratio


Rockwell C Hardness

23 to 43

Shear Modulus

45 GPa 6.5 x 106 psi

Shear Strength

330 to 780 MPa 47 to 110 x 103 psi

Tensile Strength: Ultimate (UTS)

480 to 1380 MPa 70 to 200 x 103 psi

Tensile Strength: Yield (Proof)

160 to 1250 MPa 23 to 180 x 103 psi

Thermal Properties

Latent Heat of Fusion

230 J/g

Maximum Temperature: Mechanical

280 °C 530 °F

Melting Completion (Liquidus)

980 °C 1800 °F

Melting Onset (Solidus)

870 °C 1590 °F

Specific Heat Capacity

390 J/kg-K 0.092 BTU/lb-°F

Thermal Conductivity

110 W/m-K 61 BTU/h-ft-°F

Thermal Expansion

18 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

22 % IACS

Electrical Conductivity: Equal Weight (Specific)

23 % IACS

Otherwise Unclassified Properties


8.8 g/cm3 550 lb/ft3

Embodied Carbon

9.4 kg CO2/kg material

Embodied Energy

150 MJ/kg 63 x 103 BTU/lb

Embodied Water

310 L/kg 37 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

4.2 to 500 MJ/m3

Resilience: Unit (Modulus of Resilience)

110 to 5720 kJ/m3

Stiffness to Weight: Axial

7.6 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

15 to 44 points

Strength to Weight: Bending

16 to 31 points

Thermal Diffusivity

31 mm2/s

Thermal Shock Resistance

16 to 46 points

Alloy Composition

Among wrought copper alloys, the composition of C17200 copper is notable for including beryllium (Be) and aluminum (Al). Beryllium is used to permit precipitation hardening (which increases strength) without much effect on electrical conductivity, but at the cost of substantial toxicity. Aluminum is used to add strength and oxidation resistance.

Copper (Cu)Cu 96.1 to 98
Beryllium (Be)Be 1.8 to 2.0
Nickel (Ni)Ni 0.2 to 0.6
Iron (Fe)Fe 0 to 0.4
Silicon (Si)Si 0 to 0.2
Aluminum (Al)Al 0 to 0.2
Residualsres. 0 to 0.5

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

Followup Questions

Similar Alloys

Further Reading

ASTM B196: Standard Specification for Copper-Beryllium Alloy Rod and Bar

ASTM B194: Standard Specification for Copper-Beryllium Alloy Plate, Sheet, Strip, and Rolled Bar

Copper: Its Trade, Manufacture, Use, and Environmental Status, Gunter Joseph, 2001

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