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AWS BAg-20 (P07301) Filler Metal

AWS BAg-20 is a silver-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAg-20 is the AWS designation for this material. P07301 is the UNS number.

It has a fairly low density and a very high heat capacity among silver-based braze fillers.

The graph bars on the material properties cards below compare AWS BAg-20 to: silver-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.

Mechanical Properties

Elastic (Young's, Tensile) Modulus

93 GPa 14 x 106 psi

Poisson's Ratio


Shear Modulus

35 GPa 5.1 x 106 psi

Tensile Strength: Ultimate (UTS)

160 MPa 23 x 103 psi

Thermal Properties

Brazing Temperature

770 to 900 °C 1410 to 1650 °F

Latent Heat of Fusion

150 J/g

Melting Completion (Liquidus)

770 °C 1410 °F

Melting Onset (Solidus)

680 °C 1250 °F

Specific Heat Capacity

340 J/kg-K 0.082 BTU/lb-°F

Thermal Expansion

21 µm/m-K

Otherwise Unclassified Properties


8.6 g/cm3 540 lb/ft3

Embodied Carbon

30 kg CO2/kg material

Embodied Energy

480 MJ/kg 210 x 103 BTU/lb

Common Calculations

Stiffness to Weight: Axial

6.0 points

Stiffness to Weight: Bending

17 points

Strength to Weight: Axial

5.1 points

Strength to Weight: Bending

7.6 points

Thermal Shock Resistance

5.9 points

Alloy Composition

Copper (Cu)Cu 37 to 39
Zinc (Zn)Zn 30 to 34
Silver (Ag)Ag 29 to 31
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