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Solder & Low-Melting Alloy Pb50Sn50 vs Pb80Sn20

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb50Sn50 and Pb80Sn20 are both solder & low-melting alloy grades. Pb50Sn50 is the stronger of the two: yield strength 27 MPa (3.92 ksi) against 14 MPa (2.03 ksi) for Pb80Sn20, about 93% more; tensile strength follows at 42 MPa (6.09 ksi) vs 27 MPa (3.92 ksi). Pb50Sn50 is the more ductile: elongation 55% versus 40% for Pb80Sn20, and Pb50Sn50 is harder (14 HB vs 11 HB). Pb50Sn50 is lighter (8.85 g/cm³ vs 10.2 g/cm³ for Pb80Sn20) and Pb50Sn50 conducts heat better (50 W/m·K vs 40 W/m·K).

Pb50Sn50Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.

Pb50Sn50 vs Pb80Sn20: properties

Pb50Sn50Pb80Sn20

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

8.5 GPa1.2 Msi
8.2 GPa1.2 Msi

Bulk Modulus

36 GPa5.2 Msi
46 GPa6.7 Msi

Poisson's Ratio

0.4
0.42

Tensile Strength (Ultimate)

42 MPa6.1 ksi
27 MPa3.9 ksi

Yield Strength (0.2% offset)

27 MPa3.9 ksi
14 MPa2 ksi

Elongation at Break

55%
40%

Shear Strength

34 MPa4.9 ksi
21 MPa3 ksi

Fatigue Strength (Endurance Limit)

14 MPa2 ksi
—

Hardness, Brinell

14 HB
11 HB

Hardness, Vickers

13 HV
—

Same in both: Elastic (Young's) Modulus 23 GPa3.3 Msi

Physical

Density and transition temperatures.

Density

8.85 g/cm³0.32 lb/in³
10.2 g/cm³0.37 lb/in³

Liquidus Temperature

216°C421 °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

50 W/m·K28.9 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

42 J/g18.1 BTU/lb
30 J/g12.9 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

10.9 % IACS
8.7 % IACS

Electrical Resistivity

1.58×10⁻⁷ Ω·m6.22 µΩ·in
1.98×10⁻⁷ Ω·m7.8 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.32 V
-0.5 V

Corrosion Resistance

45 / 100
40 / 100

Manufacturability

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

Machinability

30 / 100
35 / 100

Machinability Rating (AISI 1212 = 100 %)

35%
—

Weldability

15 / 100
20 / 100

Formability (cold)

95 / 100
85 / 100

Castability

90 / 100
80 / 100

Brazeability / Solderability

98 / 100
90 / 100

Polishability

20 / 100
40 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

160 MJ/kg68,788 BTU/lb
64 MJ/kg27,515 BTU/lb

Embodied Carbon (primary production)

10.5 kg CO₂/kg
4.5 kg CO₂/kg

Embodied Water

450 L/kg53.9 gal/lb
200 L/kg24 gal/lb

Typical Recycled Content

45%
60%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

5 kN·m/kg
3 kN·m/kg

Specific Stiffness (E / density)

2.6 MN·m/kg
2.3 MN·m/kg

Modulus of Resilience

16 kJ/m³
4 kJ/m³

Thermal Diffusivity

32.1 mm²/s
26.1 mm²/s

Thermal Shock Resistance Index

4
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 scalePb50Sn50Pb80Sn20

Manufacturing and finishing

CapabilityPb50Sn50Pb80Sn20
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb50Sn50 vs Pb80Sn20 — frequently asked

Is Pb50Sn50 stronger than Pb80Sn20?

Yes. Pb50Sn50 has a typical yield strength of 27 MPa (3.92 ksi) against 14 MPa (2.03 ksi) for Pb80Sn20 — about 93% more. Tensile strength is 42 MPa (6.09 ksi) vs 27 MPa (3.92 ksi).

Which is cheaper, Pb50Sn50 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, Pb50Sn50 or Pb80Sn20?

Pb80Sn20. Its machinability rates fair (35/100) against poor (30/100) for Pb50Sn50; for welding the order is Pb80Sn20 first (poor, 20/100) then Pb50Sn50 (poor, 15/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb50Sn50 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.