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AWS BAg-4 (P07400) Filler Metal

AWS BAg-4 is a silver-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAg-4 is the AWS designation for this material. P07400 is the UNS number.

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

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

91 GPa 13 x 106 psi

Poisson's Ratio


Shear Modulus

34 GPa 5.0 x 106 psi

Tensile Strength: Ultimate (UTS)

150 MPa 22 x 103 psi

Thermal Properties

Brazing Temperature

740 to 900 °C 1370 to 1650 °F

Latent Heat of Fusion

140 J/g

Melting Completion (Liquidus)

780 °C 1430 °F

Melting Onset (Solidus)

670 °C 1240 °F

Specific Heat Capacity

330 J/kg-K 0.078 BTU/lb-°F

Thermal Expansion

21 µm/m-K

Otherwise Unclassified Properties


8.9 g/cm3 550 lb/ft3

Embodied Carbon

40 kg CO2/kg material

Embodied Energy

630 MJ/kg 270 x 103 BTU/lb

Common Calculations

Stiffness to Weight: Axial

5.7 points

Stiffness to Weight: Bending

17 points

Strength to Weight: Axial

4.7 points

Strength to Weight: Bending

7.1 points

Thermal Shock Resistance

5.7 points

Alloy Composition

Silver (Ag)Ag 39 to 41
Copper (Cu)Cu 29 to 31
Zinc (Zn)Zn 26 to 30
Nickel (Ni)Ni 1.5 to 2.5
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