# UNS C55281 (BCuP-3) Filler Metal

C55281 copper is a copper-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BCuP-3 is the AWS designation for this material. C55281 is the UNS number.

The graph bars on the material properties cards below compare C55281 copper to: copper-based braze fillers (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* 15 *x 10 ^{6} psi*

Poisson's Ratio

0.34

Shear Modulus

40 *GPa* 5.8 *x 10 ^{6} psi*

Tensile Strength: Ultimate (UTS)

190 *MPa* 28 *x 10 ^{3} psi*

## Thermal Properties

Brazing Temperature

720 to 820 *°C* 1320 to 1500 *°F*

Latent Heat of Fusion

190 *J/g*

Maximum Temperature: Mechanical

200 *°C* 390 *°F*

Melting Completion (Liquidus)

810 *°C* 1500 *°F*

Melting Onset (Solidus)

640 *°C* 1190 *°F*

Specific Heat Capacity

400 *J/kg-K* 0.1 *BTU/lb-°F*

Thermal Expansion

16 *µm/m-K*

## Otherwise Unclassified Properties

Density

8.7 *g/cm ^{3}* 540

*lb/ft*

^{3}Embodied Carbon

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

Embodied Energy

110 *MJ/kg* 48 *x 10 ^{3} BTU/lb*

## Common Calculations

Stiffness to Weight: Axial

6.9 *points*

Stiffness to Weight: Bending

18 *points*

Strength to Weight: Axial

6.1 *points*

Strength to Weight: Bending

8.5 *points*

Thermal Shock Resistance

7.7 *points*

## Alloy Composition

Cu | 88.5 to 89.4 | |

P | 5.8 to 6.2 | |

Ag | 4.8 to 5.2 | |

res. | 0 to 0.15 |

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

## Followup Questions

## Similar Alloys

## Further Reading

AWS A5.8: Specification for Filler Metals for Brazing and Braze Welding

Properties and Selection: Nonferrous Alloys and Special-Purpose Materials, ASM Handbook vol. 2, ASM International, 1993