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UNS C28000 (CW509L) Muntz Metal

C28000 Muntz Metal is a brass formulated for primary forming into wrought products. CW509L is the EN numeric designation for this material. C28000 is the UNS number. Additionally, the EN chemical designation is CuZn40. The British Standard (BS) designation is CZ109. And the common industry name is 60-40 Muntz Metal.

The properties of C28000 Muntz Metal include eight 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 C28000 Muntz Metal to: wrought brasses (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

100 GPa 15 x 106 psi

Elongation at Break

10 to 45 %

Poisson's Ratio


Rockwell B Hardness

55 to 78

Shear Modulus

40 GPa 5.8 x 106 psi

Shear Strength

230 to 330 MPa 33 to 48 x 103 psi

Tensile Strength: Ultimate (UTS)

330 to 610 MPa 47 to 88 x 103 psi

Tensile Strength: Yield (Proof)

150 to 370 MPa 22 to 54 x 103 psi

Thermal Properties

Latent Heat of Fusion

170 J/g

Maximum Temperature: Mechanical

120 °C 250 °F

Melting Completion (Liquidus)

900 °C 1660 °F

Melting Onset (Solidus)

900 °C 1650 °F

Specific Heat Capacity

390 J/kg-K 0.092 BTU/lb-°F

Thermal Conductivity

120 W/m-K 71 BTU/h-ft-°F

Thermal Expansion

21 µm/m-K

Electrical Properties

Electrical Conductivity: Equal Volume

28 % IACS

Electrical Conductivity: Equal Weight (Specific)

31 % IACS

Otherwise Unclassified Properties

Base Metal Price

23 % relative


8.0 g/cm3 500 lb/ft3

Embodied Carbon

2.7 kg CO2/kg material

Embodied Energy

46 MJ/kg 20 x 103 BTU/lb

Embodied Water

320 L/kg 38 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

27 to 240 MJ/m3

Resilience: Unit (Modulus of Resilience)

110 to 670 kJ/m3

Stiffness to Weight: Axial

7.2 points

Stiffness to Weight: Bending

20 points

Strength to Weight: Axial

11 to 21 points

Strength to Weight: Bending

13 to 20 points

Thermal Diffusivity

40 mm2/s

Thermal Shock Resistance

11 to 20 points

Alloy Composition

Among wrought copper alloys, the composition of C28000 Muntz Metal is notable for containing comparatively high amounts of lead (Pb) and iron (Fe). Lead is used to improve machinability and bearing properties, at the cost of toxicity. Iron is used to increase strength inexpensively.

Copper (Cu)Cu 59 to 63
Zinc (Zn)Zn 36.3 to 41
Lead (Pb)Pb 0 to 0.3
Iron (Fe)Fe 0 to 0.070
Residualsres. 0 to 0.3

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

Followup Questions

Similar Alloys

Further Reading

ASTM B111: Standard Specification for Copper and Copper-Alloy Seamless Condenser Tubes and Ferrule Stock

ASTM B36: Standard Specification for Brass 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