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Solder & Low-Melting Alloy Pb60Sn40 vs Pb85Sn15

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb60Sn40 and Pb85Sn15 are both solder & low-melting alloy grades. Pb60Sn40 is the stronger of the two: yield strength 24 MPa (3.48 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15, about 85% more; tensile strength follows at 38 MPa (5.51 ksi) vs 25 MPa (3.63 ksi). Pb60Sn40 is harder — 12 HB against 10 HB for Pb85Sn15 — which matters for wear surfaces and threads. Pb60Sn40 is lighter (9.29 g/cm³ vs 10.5 g/cm³ for Pb85Sn15) and Pb60Sn40 conducts heat better (44 W/m·K vs 38 W/m·K). On the shop floor, Pb85Sn15 machines more easily (very good vs poor).

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

Pb85Sn15Choose it when the part is machined in volume.

Pb60Sn40 vs Pb85Sn15: properties

Pb60Sn40Pb85Sn15

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
42 GPa6.1 Msi

Tensile Strength (Ultimate)

38 MPa5.5 ksi
25 MPa3.6 ksi

Yield Strength (0.2% offset)

24 MPa3.5 ksi
13 MPa1.9 ksi

Shear Strength

28 MPa4.1 ksi
19 MPa2.8 ksi

Fatigue Strength (Endurance Limit)

12 MPa1.7 ksi
8 MPa1.2 ksi

Hardness, Brinell

12 HB
10 HB

Hardness, Vickers

—
11 HV

Same in both: Poisson's Ratio 0.4 · Elongation at Break 40%

Physical

Density and transition temperatures.

Density

9.29 g/cm³0.34 lb/in³
10.5 g/cm³0.38 lb/in³

Melting Point (Solidus)

183°C361 °F
227°C441 °F

Liquidus Temperature

238°C460 °F
288°C550 °F

Thermal

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

Thermal Conductivity

44 W/m·K25.4 BTU/hr·ft·°F
38 W/m·K22 BTU/hr·ft·°F

Specific Heat Capacity

176 J/kg·K0.04 BTU/lb·°F
145 J/kg·K0.03 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

24.5 µm/m·K13.6 µin/in·°F
27 µm/m·K15 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 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
2.15×10⁻⁷ Ω·m8.46 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

40 / 100
42 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V

Manufacturability

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

Machinability

30 / 100
75 / 100

Formability (cold)

90 / 100
95 / 100

Brazeability / Solderability

95 / 100
88 / 100

Polishability

30 / 100
25 / 100

Same in both: Weldability 20 / 100 · Castability 90 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

145 MJ/kg62,339 BTU/lb
53 MJ/kg22,786 BTU/lb

Embodied Carbon (primary production)

7.6 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

300 L/kg35.9 gal/lb
180 L/kg21.6 gal/lb

Typical Recycled Content

55%
60%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

4 kN·m/kg
2 kN·m/kg

Specific Stiffness (E / density)

2.6 MN·m/kg
2.2 MN·m/kg

Modulus of Resilience

12 kJ/m³
4 kJ/m³

Thermal Diffusivity

26.9 mm²/s
25 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 scalePb60Sn40Pb85Sn15

Manufacturing and finishing

CapabilityPb60Sn40Pb85Sn15
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb60Sn40 vs Pb85Sn15 — frequently asked

Is Pb60Sn40 stronger than Pb85Sn15?

Yes. Pb60Sn40 has a typical yield strength of 24 MPa (3.48 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15 — about 85% more. Tensile strength is 38 MPa (5.51 ksi) vs 25 MPa (3.63 ksi).

Which is cheaper, Pb60Sn40 or Pb85Sn15?

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 Pb85Sn15?

Pb85Sn15. Its machinability rates very good (75/100) against poor (30/100) for Pb60Sn40.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb60Sn40 and Pb85Sn15 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.