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Solder & Low-Melting Alloy Pb60Sn40 vs Pb80Sn20

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb60Sn40 and Pb80Sn20 are both solder & low-melting alloy grades. Pb60Sn40 is the stronger of the two: yield strength 24 MPa (3.48 ksi) against 14 MPa (2.03 ksi) for Pb80Sn20, about 71% more; tensile strength follows at 38 MPa (5.51 ksi) vs 27 MPa (3.92 ksi). Pb60Sn40 is harder — 12 HB against 11 HB for Pb80Sn20 — which matters for wear surfaces and threads. Pb60Sn40 is lighter (9.29 g/cm³ vs 10.2 g/cm³ for Pb80Sn20) and Pb60Sn40 conducts electricity better (10.1 % IACS vs 8.7 % IACS).

Pb60Sn40Choose it when strength drives the design, or when surface hardness matters.

Pb60Sn40 vs Pb80Sn20: properties

Pb60Sn40Pb80Sn20

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

24 GPa3.5 Msi
23 GPa3.3 Msi

Shear Modulus

9 GPa1.3 Msi
8.2 GPa1.2 Msi

Bulk Modulus

33 GPa4.8 Msi
46 GPa6.7 Msi

Poisson's Ratio

0.4
0.42

Tensile Strength (Ultimate)

38 MPa5.5 ksi
27 MPa3.9 ksi

Yield Strength (0.2% offset)

24 MPa3.5 ksi
14 MPa2 ksi

Shear Strength

28 MPa4.1 ksi
21 MPa3 ksi

Fatigue Strength (Endurance Limit)

12 MPa1.7 ksi
—

Hardness, Brinell

12 HB
11 HB

Same in both: Elongation at Break 40%

Physical

Density and transition temperatures.

Density

9.29 g/cm³0.34 lb/in³
10.2 g/cm³0.37 lb/in³

Liquidus Temperature

238°C460 °F
277°C531 °F

Same in both: Melting Point (Solidus) 183°C361 °F

Thermal

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

Thermal Conductivity

44 W/m·K25.4 BTU/hr·ft·°F
40 W/m·K23.1 BTU/hr·ft·°F

Specific Heat Capacity

176 J/kg·K0.04 BTU/lb·°F
150 J/kg·K0.04 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

24.5 µm/m·K13.6 µin/in·°F
26.5 µm/m·K14.7 µin/in·°F

Latent Heat of Fusion

41 J/g17.6 BTU/lb
30 J/g12.9 BTU/lb

Min Service Temperature

-55°C-67 °F
-60°C-76 °F

Same in both: Max Service Temperature (continuous) 100°C212 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10.1 % IACS
8.7 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
1.98×10⁻⁷ Ω·m7.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V · Corrosion Resistance 40 / 100

Manufacturability

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

Machinability

30 / 100
35 / 100

Formability (cold)

90 / 100
85 / 100

Castability

90 / 100
80 / 100

Brazeability / Solderability

95 / 100
90 / 100

Polishability

30 / 100
40 / 100

Same in both: Weldability 20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

145 MJ/kg62,339 BTU/lb
64 MJ/kg27,515 BTU/lb

Embodied Carbon (primary production)

7.6 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

300 L/kg35.9 gal/lb
200 L/kg24 gal/lb

Typical Recycled Content

55%
60%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

4 kN·m/kg
3 kN·m/kg

Specific Stiffness (E / density)

2.6 MN·m/kg
2.3 MN·m/kg

Modulus of Resilience

12 kJ/m³
4 kJ/m³

Thermal Diffusivity

26.9 mm²/s
26.1 mm²/s

Thermal Shock Resistance Index

3
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 scalePb60Sn40Pb80Sn20

Manufacturing and finishing

CapabilityPb60Sn40Pb80Sn20
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb60Sn40 vs Pb80Sn20 — frequently asked

Is Pb60Sn40 stronger than Pb80Sn20?

Yes. Pb60Sn40 has a typical yield strength of 24 MPa (3.48 ksi) against 14 MPa (2.03 ksi) for Pb80Sn20 — about 71% more. Tensile strength is 38 MPa (5.51 ksi) vs 27 MPa (3.92 ksi).

Which is cheaper, Pb60Sn40 or Pb80Sn20?

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, Pb60Sn40 or Pb80Sn20?

Pb80Sn20. Its machinability rates fair (35/100) against poor (30/100) for Pb60Sn40.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb60Sn40 and Pb80Sn20 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.