ISO Solder Alloy 301 (IEC B580, Bi58Sn42)
Solder alloy 301 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. B580 is the IEC 60672 type for this material. 301 is the ISO numeric designation. Older literature may refer to this material as S-Bi58Sn42, but this is now discouraged.
It has a moderately low melting temperature among alloys in the same category. In addition, it has a moderately high ductility and a moderately low heat capacity.
The graph bars on the material properties cards below compare solder alloy 301 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
23
Elastic (Young's, Tensile) Modulus
40 GPa 5.7 x 106 psi
Elongation at Break
51 %
Poisson's Ratio
0.34
Shear Modulus
15 GPa 2.1 x 106 psi
Tensile Strength: Ultimate (UTS)
55 MPa 8.0 x 103 psi
Tensile Strength: Yield (Proof)
49 MPa 7.1 x 103 psi
Thermal Properties
Latent Heat of Fusion
55 J/g
Melting Completion (Liquidus)
140 °C 280 °F
Melting Onset (Solidus)
140 °C 280 °F
Specific Heat Capacity
160 J/kg-K 0.039 BTU/lb-°F
Thermal Conductivity
19 W/m-K 11 BTU/h-ft-°F
Thermal Expansion
14 µm/m-K
Electrical Properties
Electrical Conductivity: Equal Volume
4.7 % IACS
Electrical Conductivity: Equal Weight (Specific)
4.9 % IACS
Otherwise Unclassified Properties
Density
8.7 g/cm3 550 lb/ft3
Embodied Carbon
13 kg CO2/kg material
Embodied Energy
210 MJ/kg 89 x 103 BTU/lb
Common Calculations
Resilience: Ultimate (Unit Rupture Work)
27 MJ/m3
Resilience: Unit (Modulus of Resilience)
30 kJ/m3
Stiffness to Weight: Axial
2.5 points
Stiffness to Weight: Bending
13 points
Strength to Weight: Axial
1.8 points
Strength to Weight: Bending
3.7 points
Thermal Diffusivity
13 mm2/s
Thermal Shock Resistance
7.2 points
Alloy Composition
| Bi | 56.5 to 59 | |
| Sn | 41 to 43 | |
| Ag | 0 to 0.1 | |
| Sb | 0 to 0.1 | |
| In | 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