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AWS BAg-37 (P07253) Filler Metal

AWS BAg-37 is a silver-based filler metal for brazing. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. BAg-37 is the AWS designation for this material. P07253 is the UNS number.

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

The graph bars on the material properties cards below compare AWS BAg-37 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

94 GPa 14 x 106 psi

Poisson's Ratio


Shear Modulus

36 GPa 5.2 x 106 psi

Tensile Strength: Ultimate (UTS)

180 MPa 26 x 103 psi

Thermal Properties

Brazing Temperature

780 to 890 °C 1430 to 1630 °F

Latent Heat of Fusion

150 J/g

Melting Completion (Liquidus)

780 °C 1430 °F

Melting Onset (Solidus)

690 °C 1270 °F

Specific Heat Capacity

350 J/kg-K 0.083 BTU/lb-°F

Thermal Expansion

21 µm/m-K

Otherwise Unclassified Properties


8.5 g/cm3 530 lb/ft3

Embodied Carbon

26 kg CO2/kg material

Embodied Energy

410 MJ/kg 180 x 103 BTU/lb

Common Calculations

Stiffness to Weight: Axial

6.1 points

Stiffness to Weight: Bending

18 points

Strength to Weight: Axial

5.9 points

Strength to Weight: Bending

8.3 points

Thermal Shock Resistance

6.6 points

Alloy Composition

Copper (Cu)Cu 39 to 41
Zinc (Zn)Zn 31 to 35
Silver (Ag)Ag 24 to 26
Tin (Sn)Sn 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