ISO Solder Alloy 601 (IEC B520, In52Sn48)
Solder alloy 601 is an alloy that does not fit into any substantial classification group in the database. Cited properties are appropriate for the as-fabricated (no temper or treatment) condition. B520 is the IEC 60672 type for this material. 601 is the ISO numeric designation. Older literature may refer to this material as S-In52Sn48, but this is now discouraged.
It has the lowest melting temperature among alloys in the same category. In addition, it has the highest ductility and the lowest tensile strength.
The graph bars on the material properties cards below compare solder alloy 601 to: minor element 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
Brinell Hardness
5.0
Elastic (Young's, Tensile) Modulus
31 GPa 4.5 x 106 psi
Elongation at Break
83 %
Poisson's Ratio
0.41
Shear Modulus
11 GPa 1.6 x 106 psi
Tensile Strength: Ultimate (UTS)
12 MPa 1.7 x 103 psi
Thermal Properties
Latent Heat of Fusion
43 J/g
Melting Completion (Liquidus)
120 °C 240 °F
Melting Onset (Solidus)
120 °C 240 °F
Specific Heat Capacity
230 J/kg-K 0.054 BTU/lb-°F
Thermal Conductivity
34 W/m-K 20 BTU/h-ft-°F
Thermal Expansion
23 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
12 % IACS
Electrical Conductivity: Equal Weight (Specific)
14 % IACS
Otherwise Unclassified Properties
Density
7.3 g/cm3 460 lb/ft3
Embodied Water
1330 L/kg 160 gal/lb
Common Calculations
Stiffness to Weight: Axial
2.3 points
Stiffness to Weight: Bending
14 points
Strength to Weight: Axial
0.45 points
Strength to Weight: Bending
1.6 points
Thermal Diffusivity
20 mm2/s
Thermal Shock Resistance
1.2 points
Alloy Composition
| In | 51 to 52.5 | |
| Sn | 47.5 to 48.5 | |
| Bi | 0 to 0.1 | |
| Ag | 0 to 0.1 | |
| Sb | 0 to 0.1 | |
| Pb | 0 to 0.070 | |
| Cu | 0 to 0.050 | |
| 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
Further Reading
ISO 9453: Soft solder alloys - Chemical compositions and forms