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Solder & Low-Melting Alloy Pb60Sn40 vs Pb70Sn30

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb60Sn40 and Pb70Sn30 are both solder & low-melting alloy grades. Pb60Sn40 is the stronger of the two: yield strength 24 MPa (3.48 ksi) against 22 MPa (3.19 ksi) for Pb70Sn30, about 9% more. In exchange, Pb70Sn30 is the more ductile: elongation 45% versus 40% for Pb60Sn40. Pb60Sn40 is lighter (9.29 g/cm³ vs 9.7 g/cm³ for Pb70Sn30) and Pb60Sn40 conducts electricity better (10.1 % IACS vs 9 % IACS).

Pb60Sn40Choose it when strength drives the design, or when weight is the constraint.

Pb70Sn30Choose it when the part is bent, formed or impact-loaded.

Pb60Sn40 vs Pb70Sn30: properties

Pb60Sn40Pb70Sn30

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

24 GPa3.5 Msi
25 GPa3.6 Msi

Bulk Modulus

33 GPa4.8 Msi
42 GPa6.1 Msi

Yield Strength (0.2% offset)

24 MPa3.5 ksi
22 MPa3.2 ksi

Elongation at Break

40%
45%

Shear Strength

28 MPa4.1 ksi
26 MPa3.8 ksi

Fatigue Strength (Endurance Limit)

12 MPa1.7 ksi
—

Same in both: Shear Modulus 9 GPa1.3 Msi · Poisson's Ratio 0.4 · Tensile Strength (Ultimate) 38 MPa5.5 ksi · Hardness, Brinell 12 HB

Physical

Density and transition temperatures.

Density

9.29 g/cm³0.34 lb/in³
9.7 g/cm³0.35 lb/in³

Liquidus Temperature

238°C460 °F
255°C491 °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
46 W/m·K26.6 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

24.5 µm/m·K13.6 µin/in·°F
26 µm/m·K14.4 µin/in·°F

Latent Heat of Fusion

41 J/g17.6 BTU/lb
40 J/g17.2 BTU/lb

Same in both: Max Service Temperature (continuous) 100°C212 °F · Min Service Temperature -55°C-67 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10.1 % IACS
9 % IACS

Electrical Resistivity

1.7×10⁻⁷ Ω·m6.69 µΩ·in
1.9×10⁻⁷ Ω·m7.48 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.5 V
-0.53 V

Corrosion Resistance

40 / 100
55 / 100

Manufacturability

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

Weldability

20 / 100
15 / 100

Castability

90 / 100
85 / 100

Brazeability / Solderability

95 / 100
92 / 100

Polishability

30 / 100
35 / 100

Same in both: Machinability 30 / 100 · Formability (cold) 90 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

145 MJ/kg62,339 BTU/lb
96 MJ/kg41,273 BTU/lb

Embodied Carbon (primary production)

7.6 kg CO₂/kg
6.1 kg CO₂/kg

Typical Recycled Content

55%
45%

Same in both: Embodied Water 300 L/kg35.9 gal/lb

Common Calculations

Ratios derived from the values above.

Modulus of Resilience

12 kJ/m³
10 kJ/m³

Thermal Diffusivity

26.9 mm²/s
30.6 mm²/s

Same in both: Specific Strength (UTS / density) 4 kN·m/kg · Specific Stiffness (E / density) 2.6 MN·m/kg · Thermal Shock Resistance Index 3

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 scalePb60Sn40Pb70Sn30

Manufacturing and finishing

CapabilityPb60Sn40Pb70Sn30
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb60Sn40 vs Pb70Sn30 — frequently asked

Is Pb60Sn40 stronger than Pb70Sn30?

Yes. Pb60Sn40 has a typical yield strength of 24 MPa (3.48 ksi) against 22 MPa (3.19 ksi) for Pb70Sn30 — about 9% more. Tensile strength is 38 MPa (5.51 ksi) vs 38 MPa (5.51 ksi).

Which is cheaper, Pb60Sn40 or Pb70Sn30?

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 welds better, Pb60Sn40 or Pb70Sn30?

Pb60Sn40. Its weldability rates poor (20/100) against poor (15/100) for Pb70Sn30.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb60Sn40 and Pb70Sn30 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.