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Solder & Low-Melting Alloy Bi32.5In51Sn16.5 vs Bi58Sn42

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Bi32.5In51Sn16.5 and Bi58Sn42 are both solder & low-melting alloy grades. Bi58Sn42 is the stronger of the two: yield strength 42 MPa (6.09 ksi) against 8 MPa (1.16 ksi) for Bi32.5In51Sn16.5, about 5.3 times as much; tensile strength follows at 65 MPa (9.43 ksi) vs 15 MPa (2.18 ksi). In exchange, Bi32.5In51Sn16.5 is the more ductile: elongation 100% versus 40% for Bi58Sn42, and Bi58Sn42 is harder (22 HB vs 10 HB). Bi32.5In51Sn16.5 is lighter (7.88 g/cm³ vs 8.56 g/cm³ for Bi58Sn42) and Bi58Sn42 is stiffer (42 GPa vs 10 GPa).

Bi32.5In51Sn16.5Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

Bi58Sn42Choose it when strength drives the design, or when the part sees heat.

Bi32.5In51Sn16.5 vs Bi58Sn42: properties

Bi32.5In51Sn16.5Bi58Sn42

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

10 GPa1.5 Msi
42 GPa6.1 Msi

Shear Modulus

3.6 GPa0.52 Msi
16 GPa2.3 Msi

Bulk Modulus

40 GPa5.8 Msi
41 GPa5.9 Msi

Poisson's Ratio

0.38
0.33

Tensile Strength (Ultimate)

15 MPa2.2 ksi
65 MPa9.4 ksi

Yield Strength (0.2% offset)

8 MPa1.2 ksi
42 MPa6.1 ksi

Elongation at Break

100%
40%

Compressive Strength

20 MPa2.9 ksi
—

Shear Strength

9 MPa1.3 ksi
45 MPa6.5 ksi

Hardness, Brinell

10 HB
22 HB

Fatigue Strength (Endurance Limit)

—
20 MPa2.9 ksi

Hardness, Vickers

—
23 HV

Physical

Density and transition temperatures.

Density

7.88 g/cm³0.28 lb/in³
8.56 g/cm³0.31 lb/in³

Melting Point (Solidus)

62°C144 °F
138°C280 °F

Liquidus Temperature

62°C144 °F
138°C280 °F

Thermal

How each material carries heat and how hot it can run.

Specific Heat Capacity

200 J/kg·K0.05 BTU/lb·°F
167 J/kg·K0.04 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

23 µm/m·K12.8 µin/in·°F
15 µm/m·K8.3 µin/in·°F

Latent Heat of Fusion

30 J/g12.9 BTU/lb
45 J/g19.3 BTU/lb

Max Service Temperature (continuous)

40°C104 °F
80°C176 °F

Min Service Temperature

-50°C-58 °F
-40°C-40 °F

Same in both: Thermal Conductivity 19 W/m·K11 BTU/hr·ft·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

3.4 % IACS
5 % IACS

Electrical Resistivity

5×10⁻⁷ Ω·m19.7 µΩ·in
3.4×10⁻⁷ Ω·m13.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

55 / 100
50 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.45 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Formability (cold)

85 / 100
60 / 100

Castability

95 / 100
90 / 100

Brazeability / Solderability

90 / 100
95 / 100

Polishability

25 / 100
30 / 100

Same in both: Machinability 30 / 100 · Weldability 20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

1,100 MJ/kg472,915 BTU/lb
190 MJ/kg81,685 BTU/lb

Embodied Carbon (primary production)

70 kg CO₂/kg
11 kg CO₂/kg

Typical Recycled Content

60%
25%

Embodied Water

—
500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2 kN·m/kg
8 kN·m/kg

Specific Stiffness (E / density)

1.3 MN·m/kg
4.9 MN·m/kg

Modulus of Resilience

3 kJ/m³
21 kJ/m³

Thermal Diffusivity

12.1 mm²/s
13.3 mm²/s

Thermal Shock Resistance Index

1
2

Strength versus weight

Yield strength against density for every solder & low-melting alloy grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

125102050891011Density (g/cm³)Yield strength (MPa) — log scaleBi58Sn42Bi32.5In51Sn16.5

Manufacturing and finishing

CapabilityBi32.5In51Sn16.5Bi58Sn42
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Bi32.5In51Sn16.5 vs Bi58Sn42 — frequently asked

Is Bi58Sn42 stronger than Bi32.5In51Sn16.5?

Yes. Bi58Sn42 has a typical yield strength of 42 MPa (6.09 ksi) against 8 MPa (1.16 ksi) for Bi32.5In51Sn16.5 — about 5.3 times as much. Tensile strength is 65 MPa (9.43 ksi) vs 15 MPa (2.18 ksi).

Which is cheaper, Bi32.5In51Sn16.5 or Bi58Sn42?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

When should I choose Bi32.5In51Sn16.5 over Bi58Sn42?

Pick Bi32.5In51Sn16.5 when the part is bent, formed or impact-loaded, or when weight is the constraint. Pick Bi58Sn42 when strength drives the design, or when the part sees heat.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Bi32.5In51Sn16.5 and Bi58Sn42 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.