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Solder & Low-Melting Alloy Bi42.5Pb37.7Sn11.3Cd8.5 vs Bi58Sn42

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Bi42.5Pb37.7Sn11.3Cd8.5 and Bi58Sn42 are both solder & low-melting alloy grades. Bi58Sn42 is the stronger of the two: yield strength 42 MPa (6.09 ksi) against 30 MPa (4.35 ksi) for Bi42.5Pb37.7Sn11.3Cd8.5, about 40% more; tensile strength follows at 65 MPa (9.43 ksi) vs 40 MPa (5.8 ksi). Bi58Sn42 is the more ductile: elongation 40% versus 2% for Bi42.5Pb37.7Sn11.3Cd8.5, and Bi58Sn42 is harder (22 HB vs 13 HB). Bi58Sn42 is lighter (8.56 g/cm³ vs 9.4 g/cm³ for Bi42.5Pb37.7Sn11.3Cd8.5) and Bi58Sn42 is stiffer (42 GPa vs 26 GPa). On the shop floor, Bi42.5Pb37.7Sn11.3Cd8.5 machines more easily (fair vs poor) and Bi58Sn42 welds better (poor vs not recommended).

Bi42.5Pb37.7Sn11.3Cd8.5Choose it when the part is machined in volume.

Bi58Sn42Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

Bi42.5Pb37.7Sn11.3Cd8.5 vs Bi58Sn42: properties

Bi42.5Pb37.7Sn11.3Cd8.5Bi58Sn42

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

26 GPa3.8 Msi
42 GPa6.1 Msi

Shear Modulus

10 GPa1.5 Msi
16 GPa2.3 Msi

Poisson's Ratio

0.37
0.33

Tensile Strength (Ultimate)

40 MPa5.8 ksi
65 MPa9.4 ksi

Yield Strength (0.2% offset)

30 MPa4.4 ksi
42 MPa6.1 ksi

Elongation at Break

2%
40%

Compressive Strength

65 MPa9.4 ksi
—

Shear Strength

28 MPa4.1 ksi
45 MPa6.5 ksi

Hardness, Brinell

13 HB
22 HB

Hardness, Vickers

14 HV
23 HV

Bulk Modulus

—
41 GPa5.9 Msi

Fatigue Strength (Endurance Limit)

—
20 MPa2.9 ksi

Physical

Density and transition temperatures.

Density

9.4 g/cm³0.34 lb/in³
8.56 g/cm³0.31 lb/in³

Melting Point (Solidus)

70°C158 °F
138°C280 °F

Liquidus Temperature

88°C190 °F
138°C280 °F

Thermal

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

Thermal Conductivity

16 W/m·K9.2 BTU/hr·ft·°F
19 W/m·K11 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

22 µm/m·K12.2 µin/in·°F
15 µm/m·K8.3 µin/in·°F

Latent Heat of Fusion

38 J/g16.3 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: Specific Heat Capacity 167 J/kg·K0.04 BTU/lb·°F

Electrical

Conductivity and insulation.

Electrical Conductivity

1.7 % IACS
5 % IACS

Electrical Resistivity

1×10⁻⁶ Ω·m39.4 µΩ·in
3.4×10⁻⁷ Ω·m13.4 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.5 V
-0.45 V

Corrosion Resistance

35 / 100
50 / 100

Manufacturability

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

Machinability

45 / 100
30 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
—

Weldability

5 / 100
20 / 100

Formability (cold)

25 / 100
60 / 100

Castability

95 / 100
90 / 100

Brazeability / Solderability

20 / 100
95 / 100

Polishability

40 / 100
30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

60 MJ/kg25,795 BTU/lb
190 MJ/kg81,685 BTU/lb

Embodied Carbon (primary production)

4.5 kg CO₂/kg
11 kg CO₂/kg

Typical Recycled Content

80%
25%

Embodied Water

—
500 L/kg59.9 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

4 kN·m/kg
8 kN·m/kg

Specific Stiffness (E / density)

2.8 MN·m/kg
4.9 MN·m/kg

Modulus of Resilience

17 kJ/m³
21 kJ/m³

Thermal Diffusivity

10.2 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 scaleBi58Sn42Bi42.5Pb37.7Sn11.3Cd8.5

Manufacturing and finishing

CapabilityBi42.5Pb37.7Sn11.3Cd8.5Bi58Sn42
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Bi42.5Pb37.7Sn11.3Cd8.5 vs Bi58Sn42 — frequently asked

Is Bi58Sn42 stronger than Bi42.5Pb37.7Sn11.3Cd8.5?

Yes. Bi58Sn42 has a typical yield strength of 42 MPa (6.09 ksi) against 30 MPa (4.35 ksi) for Bi42.5Pb37.7Sn11.3Cd8.5 — about 40% more. Tensile strength is 65 MPa (9.43 ksi) vs 40 MPa (5.8 ksi).

Which is cheaper, Bi42.5Pb37.7Sn11.3Cd8.5 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.

Which is easier to machine, Bi42.5Pb37.7Sn11.3Cd8.5 or Bi58Sn42?

Bi42.5Pb37.7Sn11.3Cd8.5. Its machinability rates fair (45/100) against poor (30/100) for Bi58Sn42; for welding the order is Bi58Sn42 first (poor, 20/100) then Bi42.5Pb37.7Sn11.3Cd8.5 (not recommended, 5/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Bi42.5Pb37.7Sn11.3Cd8.5 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.