UNS C18400 Chromium Copper
C18400 copper is a lightly alloyed grade of copper, formulated for primary forming into wrought products. It can have a moderately high ductility among the wrought coppers in the database.
The properties of C18400 copper include five 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 C18400 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
13 to 50 %
Poisson's Ratio
0.34
Rockwell B Hardness
16 to 84
Shear Modulus
44 GPa 6.3 x 106 psi
Shear Strength
190 to 310 MPa 27 to 44 x 103 psi
Tensile Strength: Ultimate (UTS)
270 to 490 MPa 40 to 71 x 103 psi
Tensile Strength: Yield (Proof)
110 to 480 MPa 16 to 69 x 103 psi
Thermal Properties
Latent Heat of Fusion
210 J/g
Maximum Temperature: Mechanical
200 °C 390 °F
Melting Completion (Liquidus)
1080 °C 1970 °F
Melting Onset (Solidus)
1070 °C 1960 °F
Specific Heat Capacity
390 J/kg-K 0.093 BTU/lb-°F
Thermal Conductivity
320 W/m-K 190 BTU/h-ft-°F
Thermal Expansion
17 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
80 % IACS
Electrical Conductivity: Equal Weight (Specific)
81 % IACS
Otherwise Unclassified Properties
Base Metal Price
31 % relative
Density
8.9 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
310 L/kg 37 gal/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
63 to 120 MJ/m3
Resilience: Unit (Modulus of Resilience)
54 to 980 kJ/m3
Stiffness to Weight: Axial
7.3 points
Stiffness to Weight: Bending
18 points
Strength to Weight: Axial
8.5 to 15 points
Strength to Weight: Bending
10 to 16 points
Thermal Diffusivity
94 mm2/s
Thermal Shock Resistance
9.6 to 17 points
Alloy Composition
Among wrought copper alloys, the composition of C18400 copper is notable for including chromium (Cr) and arsenic (As). Chromium additions permits certain types of heat treatment to improve mechanical strength. Arsenic is used to protect the alloy against dezincification.
| Cu | 97.2 to 99.6 | |
| Cr | 0.4 to 1.2 | |
| Zn | 0 to 0.7 | |
| Fe | 0 to 0.15 | |
| Si | 0 to 0.1 | |
| P | 0 to 0.050 | |
| Li | 0 to 0.050 | |
| Ca | 0 to 0.0050 | |
| As | 0 to 0.0050 | |
| res. | 0 to 0.5 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
Copper Alloys: Preparation, Properties and Applications, Michael Naboka and Jennifer Giordano (editors), 2013