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AWS BAu-4 (P00820) Filler Metal

AWS BAu-4 is a gold-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAu-4 is the AWS designation for this material. P00820 is the UNS number.

The graph bars on the material properties cards below compare AWS BAu-4 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

950 to 1000 °C 1740 to 1840 °F

Latent Heat of Fusion

100 J/g

Melting Completion (Liquidus)

950 °C 1740 °F

Melting Onset (Solidus)

950 °C 1740 °F

Specific Heat Capacity

190 J/kg-K 0.044 BTU/lb-°F

Thermal Expansion

14 µm/m-K

Other Material Properties


17 g/cm3 1090 lb/ft3

Elastic (Young's, Tensile) Modulus

110 GPa 17 x 106 psi

Poisson's Ratio


Shear Modulus

41 GPa 5.9 x 106 psi

Tensile Strength: Ultimate (UTS)

200 MPa 29 x 103 psi

Common Calculations

Stiffness to Weight: Axial

3.6 points

Stiffness to Weight: Bending

9.3 points

Strength to Weight: Axial

3.2 points

Strength to Weight: Bending

4.4 points

Thermal Shock Resistance

9.2 points

Alloy Composition

Gold (Au)Au 81.5 to 82.5
Nickel (Ni)Ni 17.4 to 18.5
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