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AWS BAu-1 (P00375) Filler Metal

AWS BAu-1 is a gold-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAu-1 is the AWS designation for this material. P00375 is the UNS number.

It has a moderately low density among gold-based braze fillers. In addition, it has a fairly high heat capacity and a moderately high tensile strength.

The graph bars on the material properties cards below compare AWS BAu-1 to: gold-based braze fillers (top), all alloys in the same category (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.

Thermal Properties

Brazing Temperature

1020 to 1090 °C 1860 to 2000 °F

Latent Heat of Fusion

150 J/g

Melting Completion (Liquidus)

1020 °C 1860 °F

Melting Onset (Solidus)

990 °C 1820 °F

Specific Heat Capacity

290 J/kg-K 0.069 BTU/lb-°F

Thermal Expansion

16 µm/m-K

Other Material Properties


13 g/cm3 800 lb/ft3

Elastic (Young's, Tensile) Modulus

110 GPa 16 x 106 psi

Poisson's Ratio


Shear Modulus

40 GPa 5.8 x 106 psi

Tensile Strength: Ultimate (UTS)

210 MPa 30 x 103 psi

Common Calculations

Stiffness to Weight: Axial

4.7 points

Stiffness to Weight: Bending

12 points

Strength to Weight: Axial

4.5 points

Strength to Weight: Bending

6.1 points

Thermal Shock Resistance

8.5 points

Alloy Composition

Copper (Cu)Cu 61.9 to 63
Gold (Au)Au 37 to 38
Residualsres. 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