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Solder & Low-Melting Alloy Pb85Sn15 vs Pb90Sn10

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb85Sn15 and Pb90Sn10 are both solder & low-melting alloy grades. Pb90Sn10 is the stronger of the two: yield strength 15 MPa (2.18 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15, about 15% more. In exchange, Pb85Sn15 is the more ductile: elongation 40% versus 25% for Pb90Sn10. On the shop floor, Pb85Sn15 machines more easily (very good vs poor).

Pb85Sn15Choose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.

Pb90Sn10Choose it when strength drives the design.

Pb85Sn15 vs Pb90Sn10: properties

Pb85Sn15Pb90Sn10

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

23 GPa3.3 Msi
22 GPa3.2 Msi

Shear Modulus

8.2 GPa1.2 Msi
7.6 GPa1.1 Msi

Bulk Modulus

42 GPa6.1 Msi
44 GPa6.4 Msi

Poisson's Ratio

0.4
0.42

Tensile Strength (Ultimate)

25 MPa3.6 ksi
26 MPa3.8 ksi

Yield Strength (0.2% offset)

13 MPa1.9 ksi
15 MPa2.2 ksi

Elongation at Break

40%
25%

Shear Strength

19 MPa2.8 ksi
20 MPa2.9 ksi

Fatigue Strength (Endurance Limit)

8 MPa1.2 ksi
11 MPa1.6 ksi

Hardness, Vickers

11 HV
—

Same in both: Hardness, Brinell 10 HB

Physical

Density and transition temperatures.

Density

10.5 g/cm³0.38 lb/in³
10.75 g/cm³0.39 lb/in³

Melting Point (Solidus)

227°C441 °F
268°C514 °F

Liquidus Temperature

288°C550 °F
302°C576 °F

Thermal

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

Thermal Conductivity

38 W/m·K22 BTU/hr·ft·°F
36 W/m·K20.8 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

27 µm/m·K15 µin/in·°F
29.5 µm/m·K16.4 µin/in·°F

Latent Heat of Fusion

30 J/g12.9 BTU/lb
26 J/g11.2 BTU/lb

Same in both: Max Service Temperature (continuous) 100°C212 °F · Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
8.5 % IACS

Electrical Resistivity

2.15×10⁻⁷ Ω·m8.46 µΩ·in
2.03×10⁻⁷ Ω·m7.99 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.5 V
-0.51 V

Corrosion Resistance

42 / 100
40 / 100

Manufacturability

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

Machinability

75 / 100
30 / 100

Formability (cold)

95 / 100
90 / 100

Brazeability / Solderability

88 / 100
80 / 100

Polishability

25 / 100
20 / 100

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

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

53 MJ/kg22,786 BTU/lb
49 MJ/kg21,066 BTU/lb

Embodied Carbon (primary production)

4.5 kg CO₂/kg
3.5 kg CO₂/kg

Embodied Water

180 L/kg21.6 gal/lb
110 L/kg13.2 gal/lb

Typical Recycled Content

60%
50%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

2.2 MN·m/kg
2 MN·m/kg

Modulus of Resilience

4 kJ/m³
5 kJ/m³

Thermal Diffusivity

25 mm²/s
24.3 mm²/s

Thermal Shock Resistance Index

2
1

Same in both: Specific Strength (UTS / density) 2 kN·m/kg

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 scalePb85Sn15Pb90Sn10

Manufacturing and finishing

CapabilityPb85Sn15Pb90Sn10
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb85Sn15 vs Pb90Sn10 — frequently asked

Is Pb90Sn10 stronger than Pb85Sn15?

Yes. Pb90Sn10 has a typical yield strength of 15 MPa (2.18 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15 — about 15% more. Tensile strength is 26 MPa (3.77 ksi) vs 25 MPa (3.63 ksi).

Which is cheaper, Pb85Sn15 or Pb90Sn10?

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, Pb85Sn15 or Pb90Sn10?

Pb85Sn15. Its machinability rates very good (75/100) against poor (30/100) for Pb90Sn10.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb85Sn15 and Pb90Sn10 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.