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Solder & Low-Melting Alloy Sn5Pb95 vs Sn63Pb37Sb

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Sn5Pb95 and Sn63Pb37Sb are both solder & low-melting alloy grades. Sn63Pb37Sb is the stronger of the two: yield strength 38 MPa (5.51 ksi) against 12 MPa (1.74 ksi) for Sn5Pb95, about 3.2 times as much; tensile strength follows at 58 MPa (8.41 ksi) vs 24 MPa (3.48 ksi). In exchange, Sn5Pb95 is the more ductile: elongation 45% versus 32% for Sn63Pb37Sb, and Sn63Pb37Sb is harder (16 HB vs 8 HB). Sn63Pb37Sb is lighter (8.4 g/cm³ vs 11 g/cm³ for Sn5Pb95) and Sn63Pb37Sb is stiffer (32 GPa vs 16 GPa).

Sn5Pb95Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

Sn63Pb37SbChoose it when strength drives the design, or when weight is the constraint.

Sn5Pb95 vs Sn63Pb37Sb: properties

Sn5Pb95Sn63Pb37Sb

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

16 GPa2.3 Msi
32 GPa4.6 Msi

Shear Modulus

5.6 GPa0.81 Msi
12.5 GPa1.8 Msi

Bulk Modulus

43 GPa6.2 Msi
50 GPa7.3 Msi

Poisson's Ratio

0.42
0.4

Tensile Strength (Ultimate)

24 MPa3.5 ksi
58 MPa8.4 ksi

Yield Strength (0.2% offset)

12 MPa1.7 ksi
38 MPa5.5 ksi

Elongation at Break

45%
32%

Shear Strength

15 MPa2.2 ksi
38 MPa5.5 ksi

Fatigue Strength (Endurance Limit)

8 MPa1.2 ksi
15 MPa2.2 ksi

Hardness, Brinell

8 HB
16 HB

Physical

Density and transition temperatures.

Density

11 g/cm³0.4 lb/in³
8.4 g/cm³0.3 lb/in³

Melting Point (Solidus)

308°C586 °F
183°C361 °F

Liquidus Temperature

312°C594 °F
185°C365 °F

Thermal

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

Thermal Conductivity

30 W/m·K17.3 BTU/hr·ft·°F
50 W/m·K28.9 BTU/hr·ft·°F

Specific Heat Capacity

135 J/kg·K0.03 BTU/lb·°F
170 J/kg·K0.04 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

29 µm/m·K16.1 µin/in·°F
24.5 µm/m·K13.6 µin/in·°F

Latent Heat of Fusion

25 J/g10.7 BTU/lb
42 J/g18.1 BTU/lb

Max Service Temperature (continuous)

175°C347 °F
100°C212 °F

Same in both: Min Service Temperature -55°C-67 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

8.2 % IACS
11.5 % IACS

Electrical Resistivity

2.1×10⁻⁷ Ω·m8.27 µΩ·in
1.5×10⁻⁷ Ω·m5.91 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.52 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

25 / 100
20 / 100

Formability (cold)

95 / 100
90 / 100

Castability

85 / 100
95 / 100

Brazeability / Solderability

70 / 100
100 / 100

Polishability

20 / 100
25 / 100

Weldability

—
20 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

42 MJ/kg18,057 BTU/lb
210 MJ/kg90,284 BTU/lb

Embodied Carbon (primary production)

2.6 kg CO₂/kg
11 kg CO₂/kg

Embodied Water

90 L/kg10.8 gal/lb
320 L/kg38.3 gal/lb

Typical Recycled Content

55%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

2 kN·m/kg
7 kN·m/kg

Specific Stiffness (E / density)

1.5 MN·m/kg
3.8 MN·m/kg

Modulus of Resilience

5 kJ/m³
23 kJ/m³

Thermal Diffusivity

20.2 mm²/s
35 mm²/s

Thermal Shock Resistance Index

2
4

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 scaleSn63Pb37SbSn5Pb95

Manufacturing and finishing

CapabilitySn5Pb95Sn63Pb37Sb
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Sn5Pb95 vs Sn63Pb37Sb — frequently asked

Is Sn63Pb37Sb stronger than Sn5Pb95?

Yes. Sn63Pb37Sb has a typical yield strength of 38 MPa (5.51 ksi) against 12 MPa (1.74 ksi) for Sn5Pb95 — about 3.2 times as much. Tensile strength is 58 MPa (8.41 ksi) vs 24 MPa (3.48 ksi).

Which is cheaper, Sn5Pb95 or Sn63Pb37Sb?

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, Sn5Pb95 or Sn63Pb37Sb?

Sn5Pb95, by a small margin. Both rate poor for machinability — 25/100 against 20/100 for Sn63Pb37Sb.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Sn5Pb95 and Sn63Pb37Sb 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.