ISO Solder Alloy 503 (Sn92Cu6Ag2)
Solder alloy 503 is a tin-based soldering alloy. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. 503 is the ISO numeric designation for this material. Older literature may refer to this material as S-Sn92Cu6Ag2, but this is now discouraged.
It has a moderately high heat capacity and a moderately high tensile strength among tin-based solder alloys.
The graph bars on the material properties cards below compare solder alloy 503 to: tin-based solder alloys (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
54 GPa 7.9 x 106 psi
Elongation at Break
30 %
Poisson's Ratio
0.36
Shear Modulus
20 GPa 2.9 x 106 psi
Tensile Strength: Ultimate (UTS)
57 MPa 8.3 x 103 psi
Thermal Properties
Latent Heat of Fusion
69 J/g
Melting Completion (Liquidus)
380 °C 720 °F
Melting Onset (Solidus)
220 °C 420 °F
Specific Heat Capacity
230 J/kg-K 0.055 BTU/lb-°F
Thermal Conductivity
61 W/m-K 35 BTU/h-ft-°F
Thermal Expansion
22 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
14 % IACS
Electrical Conductivity: Equal Weight (Specific)
17 % IACS
Otherwise Unclassified Properties
Density
7.5 g/cm3 470 lb/ft3
Embodied Carbon
16 kg CO2/kg material
Embodied Energy
270 MJ/kg 120 x 103 BTU/lb
Common Calculations
Stiffness to Weight: Axial
4.1 points
Stiffness to Weight: Bending
17 points
Strength to Weight: Axial
2.1 points
Strength to Weight: Bending
4.4 points
Thermal Diffusivity
35 mm2/s
Thermal Shock Resistance
3.5 points
Alloy Composition
| Sn | 90.8 to 92.7 | |
| Cu | 5.5 to 6.5 | |
| Ag | 1.8 to 2.2 | |
| Sb | 0 to 0.1 | |
| In | 0 to 0.1 | |
| Bi | 0 to 0.080 | |
| Pb | 0 to 0.070 | |
| Au | 0 to 0.050 | |
| As | 0 to 0.030 | |
| Fe | 0 to 0.020 | |
| Ni | 0 to 0.010 | |
| Cd | 0 to 0.0020 | |
| Al | 0 to 0.0010 | |
| Zn | 0 to 0.0010 |
All values are % weight. Ranges represent what is permitted under applicable standards.
Followup Questions
Similar Alloys
Further Reading
ISO 9453: Soft solder alloys - Chemical compositions and forms