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Solder & Low-Melting Alloy Pb50Sn50Sb vs Pb60Sn40

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb50Sn50Sb and Pb60Sn40 are both solder & low-melting alloy grades. Pb50Sn50Sb is the stronger of the two: yield strength 36 MPa (5.22 ksi) against 24 MPa (3.48 ksi) for Pb60Sn40, about 50% more; tensile strength follows at 48 MPa (6.96 ksi) vs 38 MPa (5.51 ksi). In exchange, Pb60Sn40 is the more ductile: elongation 40% versus 35% for Pb50Sn50Sb, and Pb50Sn50Sb is harder (15 HB vs 12 HB). Pb50Sn50Sb is lighter (8.87 g/cm³ vs 9.29 g/cm³ for Pb60Sn40) and Pb50Sn50Sb is stiffer (30 GPa vs 24 GPa). On the shop floor, Pb60Sn40 welds better (poor vs not recommended).

Pb50Sn50SbChoose it when strength drives the design, or when weight is the constraint.

Pb60Sn40Choose it when the part is bent, formed or impact-loaded, or when it will be welded.

Pb50Sn50Sb vs Pb60Sn40: properties

Pb50Sn50SbPb60Sn40

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

30 GPa4.4 Msi
24 GPa3.5 Msi

Shear Modulus

11 GPa1.6 Msi
9 GPa1.3 Msi

Bulk Modulus

36 GPa5.2 Msi
33 GPa4.8 Msi

Poisson's Ratio

0.36
0.4

Tensile Strength (Ultimate)

48 MPa7 ksi
38 MPa5.5 ksi

Yield Strength (0.2% offset)

36 MPa5.2 ksi
24 MPa3.5 ksi

Elongation at Break

35%
40%

Compressive Strength

50 MPa7.3 ksi
—

Shear Strength

38 MPa5.5 ksi
28 MPa4.1 ksi

Fatigue Strength (Endurance Limit)

16 MPa2.3 ksi
12 MPa1.7 ksi

Hardness, Brinell

15 HB
12 HB

Physical

Density and transition temperatures.

Density

8.87 g/cm³0.32 lb/in³
9.29 g/cm³0.34 lb/in³

Liquidus Temperature

216°C421 °F
238°C460 °F

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

Thermal

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

Thermal Conductivity

46 W/m·K26.6 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Latent Heat of Fusion

42 J/g18.1 BTU/lb
41 J/g17.6 BTU/lb

Min Service Temperature

-60°C-76 °F
-55°C-67 °F

Same in both: Specific Heat Capacity 176 J/kg·K0.04 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 24.5 µm/m·K13.6 µin/in·°F · Max Service Temperature (continuous) 100°C212 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

11 % IACS
10.1 % IACS

Electrical Resistivity

1.55×10⁻⁷ Ω·m6.1 µΩ·in
1.7×10⁻⁷ Ω·m6.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.32 V
-0.5 V

Corrosion Resistance

35 / 100
40 / 100

Manufacturability

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

Machinability

25 / 100
30 / 100

Weldability

10 / 100
20 / 100

Same in both: Formability (cold) 90 / 100 · Castability 90 / 100 · Brazeability / Solderability 95 / 100 · Polishability 30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

170 MJ/kg73,087 BTU/lb
145 MJ/kg62,339 BTU/lb

Embodied Carbon (primary production)

9.5 kg CO₂/kg
7.6 kg CO₂/kg

Embodied Water

220 L/kg26.4 gal/lb
300 L/kg35.9 gal/lb

Typical Recycled Content

50%
55%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

5 kN·m/kg
4 kN·m/kg

Specific Stiffness (E / density)

3.4 MN·m/kg
2.6 MN·m/kg

Modulus of Resilience

22 kJ/m³
12 kJ/m³

Thermal Diffusivity

29.5 mm²/s
26.9 mm²/s

Same in both: 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 scalePb60Sn40Pb50Sn50Sb

Manufacturing and finishing

CapabilityPb50Sn50SbPb60Sn40
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb50Sn50Sb vs Pb60Sn40 — frequently asked

Is Pb50Sn50Sb stronger than Pb60Sn40?

Yes. Pb50Sn50Sb has a typical yield strength of 36 MPa (5.22 ksi) against 24 MPa (3.48 ksi) for Pb60Sn40 — about 50% more. Tensile strength is 48 MPa (6.96 ksi) vs 38 MPa (5.51 ksi).

Which is cheaper, Pb50Sn50Sb or Pb60Sn40?

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, Pb50Sn50Sb or Pb60Sn40?

Pb60Sn40, by a small margin. Both rate poor for machinability — 30/100 against 25/100 for Pb50Sn50Sb; for welding the order is Pb60Sn40 first (poor, 20/100) then Pb50Sn50Sb (not recommended, 10/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb50Sn50Sb and Pb60Sn40 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.