UNS C21000 (CW500L) Gilding Brass
C21000 brass is a brass formulated for primary forming into wrought products. CW500L is the EN numeric designation for this material. C21000 is the UNS number. Additionally, the EN chemical designation is CuZn5. The British Standard (BS) designation is CZ125. And the common industry name is 95-5 Gilding Brass.
It has a moderately high melting temperature among wrought brasses. In addition, it can have the lowest tensile strength and has the highest thermal conductivity.
The properties of C21000 brass 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 C21000 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
110 GPa 17 x 106 psi
Elongation at Break
2.9 to 50 %
Poisson's Ratio
0.34
Rockwell B Hardness
36 to 73
Rockwell Superficial 30T Hardness
44 to 68
Shear Modulus
43 GPa 6.2 x 106 psi
Shear Strength
180 to 280 MPa 26 to 40 x 103 psi
Tensile Strength: Ultimate (UTS)
240 to 450 MPa 34 to 65 x 103 psi
Tensile Strength: Yield (Proof)
69 to 440 MPa 10 to 63 x 103 psi
Thermal Properties
Latent Heat of Fusion
200 J/g
Maximum Temperature: Mechanical
190 °C 370 °F
Melting Completion (Liquidus)
1070 °C 1950 °F
Melting Onset (Solidus)
1050 °C 1920 °F
Specific Heat Capacity
390 J/kg-K 0.092 BTU/lb-°F
Thermal Conductivity
230 W/m-K 140 BTU/h-ft-°F
Thermal Expansion
18 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
56 % IACS
Electrical Conductivity: Equal Weight (Specific)
57 % IACS
Otherwise Unclassified Properties
Base Metal Price
30 % relative
Density
8.8 g/cm3 550 lb/ft3
Embodied Carbon
2.6 kg CO2/kg material
Embodied Energy
42 MJ/kg 18 x 103 BTU/lb
Embodied Water
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
13 to 100 MJ/m3
Resilience: Unit (Modulus of Resilience)
21 to 830 kJ/m3
Stiffness to Weight: Axial
7.2 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
7.4 to 14 points
Strength to Weight: Bending
9.6 to 15 points
Thermal Diffusivity
69 mm2/s
Thermal Shock Resistance
8.1 to 15 points
Alloy Composition
Among wrought copper alloys, the composition of C21000 brass is notable for containing comparatively high amounts of iron (Fe) and lead (Pb). Iron is used to increase strength inexpensively. Lead is used to improve machinability and bearing properties, at the cost of toxicity.
| Cu | 94 to 96 | |
| Zn | 3.7 to 6.0 | |
| Fe | 0 to 0.050 | |
| Pb | 0 to 0.030 | |
| res. | 0 to 0.2 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ASTM B134: Standard Specification for Brass Wire
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