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UNS C38000 (CW624N) Leaded Brass

C38000 brass is a brass formulated for primary forming into wrought products. Cited properties are appropriate for the M20 (as hot rolled) condition. CW624N is the EN numeric designation for this material. C38000 is the UNS number. Additionally, the EN chemical designation is CuZn43Pb2Al.

It has a moderately low base cost among wrought brasses. In addition, it has the lowest melting temperature and a moderately low tensile strength.

The graph bars on the material properties cards below compare C38000 brass 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

17 %

Poisson's Ratio


Shear Modulus

39 GPa 5.7 x 106 psi

Shear Strength

230 MPa 34 x 103 psi

Tensile Strength: Ultimate (UTS)

380 MPa 55 x 103 psi

Tensile Strength: Yield (Proof)

120 MPa 18 x 103 psi

Thermal Properties

Latent Heat of Fusion

170 J/g

Maximum Temperature: Mechanical

110 °C 230 °F

Melting Completion (Liquidus)

800 °C 1470 °F

Melting Onset (Solidus)

760 °C 1400 °F

Specific Heat Capacity

380 J/kg-K 0.091 BTU/lb-°F

Thermal Conductivity

110 W/m-K 66 BTU/h-ft-°F

Thermal Expansion

21 µm/m-K

Otherwise Unclassified Properties

Base Metal Price

22 % 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

330 L/kg 39 gal/lb

Common Calculations

Resilience: Ultimate (Unit Rupture Work)

50 MJ/m3

Resilience: Unit (Modulus of Resilience)

74 kJ/m3

Stiffness to Weight: Axial

7.1 points

Stiffness to Weight: Bending

19 points

Strength to Weight: Axial

13 points

Strength to Weight: Bending

14 points

Thermal Diffusivity

37 mm2/s

Thermal Shock Resistance

13 points

Alloy Composition

Among wrought copper alloys, the composition of C38000 brass is notable for including aluminum (Al) and containing a comparatively high amount of lead (Pb). Aluminum is used to add strength and oxidation resistance. Lead is used to improve machinability and bearing properties, at the cost of toxicity.

Copper (Cu)Cu 55 to 60
Zinc (Zn)Zn 35.9 to 43.5
Lead (Pb)Pb 1.5 to 2.5
Aluminum (Al)Al 0 to 0.5
Iron (Fe)Fe 0 to 0.35
Tin (Sn)Sn 0 to 0.3
Residualsres. 0 to 0.5

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

Followup Questions

Similar Alloys

Further Reading

ASTM B455: Standard Specification for Copper-Zinc-Lead Alloy (Leaded-Brass) Extruded Shapes

ASM Specialty Handbook: Copper and Copper Alloys, J. R. Davis (editor), 2001