# UNS C82700 Beryllium-Nickel Copper

C82700 copper is a lightly alloyed grade of copper, formulated for casting. Cited properties are appropriate for the heat treated (HT) condition. It has a very low melting temperature among cast coppers. In addition, it has the highest tensile strength and a fairly low thermal conductivity.

The graph bars on the material properties cards below compare C82700 copper to: cast 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* 18 *x 10 ^{6} psi*

Elongation at Break

1.8 *%*

Poisson's Ratio

0.33

Rockwell C Hardness

39

Shear Modulus

46 *GPa* 6.7 *x 10 ^{6} psi*

Tensile Strength: Ultimate (UTS)

1200 *MPa* 170 *x 10 ^{3} psi*

Tensile Strength: Yield (Proof)

1020 *MPa* 150 *x 10 ^{3} psi*

## Thermal Properties

Latent Heat of Fusion

240 *J/g*

Maximum Temperature: Mechanical

300 *°C* 570 *°F*

Melting Completion (Liquidus)

950 *°C* 1750 *°F*

Melting Onset (Solidus)

860 *°C* 1570 *°F*

Specific Heat Capacity

380 *J/kg-K* 0.092 *BTU/lb-°F*

Thermal Conductivity

130 *W/m-K* 75 *BTU/h-ft-°F*

Thermal Expansion

17 *µm/m-K*

## Electrical Properties

Electrical Conductivity: Equal Volume

20 *% IACS*

Electrical Conductivity: Equal Weight (Specific)

21 *% IACS*

## Otherwise Unclassified Properties

Density

8.7 *g/cm ^{3}* 550

*lb/ft*

^{3}Embodied Carbon

12 *kg CO _{2}/kg material*

Embodied Energy

180 *MJ/kg* 78 *x 10 ^{3} BTU/lb*

Embodied Water

310 *L/kg* 37 *gal/lb*

## Common Calculations

Resilience: Ultimate (Unit Rupture Work)

21 *MJ/m ^{3}*

Resilience: Unit (Modulus of Resilience)

4260 *kJ/m ^{3}*

Stiffness to Weight: Axial

7.8 *points*

Stiffness to Weight: Bending

19 *points*

Strength to Weight: Axial

38 *points*

Strength to Weight: Bending

29 *points*

Thermal Diffusivity

39 *mm ^{2}/s*

Thermal Shock Resistance

41 *points*

## Alloy Composition

Among cast copper alloys, the composition of C82700 copper is notable for including beryllium (Be) and chromium (Cr). Beryllium is used to permit precipitation hardening (which increases strength) without much effect on electrical conductivity, but at the cost of substantial toxicity. Chromium additions permits certain types of heat treatment to improve mechanical strength.

Cu | 94.6 to 96.7 | |

Be | 2.4 to 2.6 | |

Ni | 1.0 to 1.5 | |

Fe | 0 to 0.25 | |

Si | 0 to 0.15 | |

Al | 0 to 0.15 | |

Sn | 0 to 0.1 | |

Zn | 0 to 0.1 | |

Cr | 0 to 0.090 | |

Pb | 0 to 0.020 | |

res. | 0 to 0.5 |

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

## Followup Questions

## Similar Alloys

## Further Reading

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