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Solder & Low-Melting Alloy Bi50Pb25Sn25 vs In52Sn48

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Bi50Pb25Sn25 and In52Sn48 are both solder & low-melting alloy grades. Bi50Pb25Sn25 is the stronger of the two: yield strength 18 MPa (2.61 ksi) against 7 MPa (1.02 ksi) for In52Sn48, about 157% more; tensile strength follows at 30 MPa (4.35 ksi) vs 12 MPa (1.73 ksi). In exchange, In52Sn48 is the more ductile: elongation 60% versus 35% for Bi50Pb25Sn25, and Bi50Pb25Sn25 is harder (11 HB vs 5 HB). In52Sn48 is lighter (7.3 g/cm³ vs 9.7 g/cm³ for Bi50Pb25Sn25) and Bi50Pb25Sn25 is stiffer (25 GPa vs 20 GPa). On the shop floor, Bi50Pb25Sn25 machines more easily (fair vs poor).

Bi50Pb25Sn25Choose it when strength drives the design, or when the part is machined in volume.

In52Sn48Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.

Bi50Pb25Sn25 vs In52Sn48: properties

Bi50Pb25Sn25In52Sn48

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

25 GPa3.6 Msi
20 GPa2.9 Msi

Shear Modulus

9 GPa1.3 Msi
—

Bulk Modulus

34 GPa4.9 Msi
—

Poisson's Ratio

0.36
0.4

Tensile Strength (Ultimate)

30 MPa4.4 ksi
12 MPa1.7 ksi

Yield Strength (0.2% offset)

18 MPa2.6 ksi
7 MPa1 ksi

Elongation at Break

35%
60%

Compressive Strength

45 MPa6.5 ksi
—

Shear Strength

22 MPa3.2 ksi
11 MPa1.6 ksi

Hardness, Brinell

11 HB
5 HB

Physical

Density and transition temperatures.

Density

9.7 g/cm³0.35 lb/in³
7.3 g/cm³0.26 lb/in³

Melting Point (Solidus)

98°C208 °F
118°C244 °F

Liquidus Temperature

110°C230 °F
118°C244 °F

Thermal

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

Thermal Conductivity

17 W/m·K9.8 BTU/hr·ft·°F
34 W/m·K19.6 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

17 µm/m·K9.4 µin/in·°F
20 µm/m·K11.1 µin/in·°F

Latent Heat of Fusion

35 J/g15 BTU/lb
28 J/g12 BTU/lb

Max Service Temperature (continuous)

50°C122 °F
60°C140 °F

Min Service Temperature

-50°C-58 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

4 % IACS
11.7 % IACS

Electrical Resistivity

4.5×10⁻⁷ Ω·m17.7 µΩ·in
1.47×10⁻⁷ Ω·m5.79 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.5 V
-0.55 V

Same in both: Corrosion Resistance 45 / 100

Manufacturability

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

Machinability

40 / 100
20 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
—

Formability (cold)

60 / 100
95 / 100

Castability

92 / 100
90 / 100

Brazeability / Solderability

95 / 100
98 / 100

Polishability

35 / 100
—

Same in both: Weldability 10 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

120 MJ/kg51,591 BTU/lb
1,600 MJ/kg687,877 BTU/lb

Embodied Carbon (primary production)

8.5 kg CO₂/kg
105 kg CO₂/kg

Embodied Water

260 L/kg31.2 gal/lb
—

Typical Recycled Content

60%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

3 kN·m/kg
2 kN·m/kg

Specific Stiffness (E / density)

2.6 MN·m/kg
2.7 MN·m/kg

Modulus of Resilience

6 kJ/m³
1 kJ/m³

Thermal Diffusivity

10.5 mm²/s
23.3 mm²/s

Same in both: Thermal Shock Resistance Index 1

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 scaleIn52Sn48Bi50Pb25Sn25

Manufacturing and finishing

CapabilityBi50Pb25Sn25In52Sn48
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Bi50Pb25Sn25 vs In52Sn48 — frequently asked

Is Bi50Pb25Sn25 stronger than In52Sn48?

Yes. Bi50Pb25Sn25 has a typical yield strength of 18 MPa (2.61 ksi) against 7 MPa (1.02 ksi) for In52Sn48 — about 157% more. Tensile strength is 30 MPa (4.35 ksi) vs 12 MPa (1.73 ksi).

Which is cheaper, Bi50Pb25Sn25 or In52Sn48?

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.

Which is easier to machine, Bi50Pb25Sn25 or In52Sn48?

Bi50Pb25Sn25. Its machinability rates fair (40/100) against poor (20/100) for In52Sn48.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Bi50Pb25Sn25 and In52Sn48 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.