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Solder & Low-Melting Alloy Sn63Pb37Sb vs Sn96Ag2.5Bi1Cu0.5

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Sn63Pb37Sb and Sn96Ag2.5Bi1Cu0.5 are both solder & low-melting alloy grades. Sn96Ag2.5Bi1Cu0.5 is the stronger of the two: yield strength 40 MPa (5.8 ksi) against 38 MPa (5.51 ksi) for Sn63Pb37Sb, about 5% more. Sn96Ag2.5Bi1Cu0.5 is lighter (7.4 g/cm³ vs 8.4 g/cm³ for Sn63Pb37Sb) and Sn96Ag2.5Bi1Cu0.5 is stiffer (48 GPa vs 32 GPa).

Sn96Ag2.5Bi1Cu0.5Choose it when strength drives the design, or when weight is the constraint.

Sn63Pb37Sb vs Sn96Ag2.5Bi1Cu0.5: properties

Sn63Pb37SbSn96Ag2.5Bi1Cu0.5

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

32 GPa4.6 Msi
48 GPa7 Msi

Shear Modulus

12.5 GPa1.8 Msi
18 GPa2.6 Msi

Bulk Modulus

50 GPa7.3 Msi
58 GPa8.4 Msi

Poisson's Ratio

0.4
0.36

Tensile Strength (Ultimate)

58 MPa8.4 ksi
52 MPa7.5 ksi

Yield Strength (0.2% offset)

38 MPa5.5 ksi
40 MPa5.8 ksi

Elongation at Break

32%
30%

Shear Strength

38 MPa5.5 ksi
32 MPa4.6 ksi

Fatigue Strength (Endurance Limit)

15 MPa2.2 ksi
20 MPa2.9 ksi

Hardness, Brinell

16 HB
—

Hardness, Vickers

—
15 HV

Physical

Density and transition temperatures.

Density

8.4 g/cm³0.3 lb/in³
7.4 g/cm³0.27 lb/in³

Melting Point (Solidus)

183°C361 °F
214°C417 °F

Liquidus Temperature

185°C365 °F
221°C430 °F

Thermal

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

Thermal Conductivity

50 W/m·K28.9 BTU/hr·ft·°F
56 W/m·K32.4 BTU/hr·ft·°F

Specific Heat Capacity

170 J/kg·K0.04 BTU/lb·°F
232 J/kg·K0.06 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

24.5 µm/m·K13.6 µin/in·°F
22 µm/m·K12.2 µin/in·°F

Latent Heat of Fusion

42 J/g18.1 BTU/lb
58 J/g24.9 BTU/lb

Max Service Temperature (continuous)

100°C212 °F
125°C257 °F

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

Electrical

Conductivity and insulation.

Electrical Conductivity

11.5 % IACS
12.5 % IACS

Electrical Resistivity

1.5×10⁻⁷ Ω·m5.91 µΩ·in
1.38×10⁻⁷ Ω·m5.43 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

40 / 100
45 / 100

Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V

Manufacturability

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

Machinability

20 / 100
25 / 100

Weldability

20 / 100
—

Castability

95 / 100
88 / 100

Brazeability / Solderability

100 / 100
97 / 100

Polishability

25 / 100
30 / 100

Same in both: Formability (cold) 90 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

210 MJ/kg90,284 BTU/lb
350 MJ/kg150,473 BTU/lb

Embodied Carbon (primary production)

11 kg CO₂/kg
22 kg CO₂/kg

Embodied Water

320 L/kg38.3 gal/lb
400 L/kg47.9 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Stiffness (E / density)

3.8 MN·m/kg
6.5 MN·m/kg

Modulus of Resilience

23 kJ/m³
17 kJ/m³

Thermal Diffusivity

35 mm²/s
32.6 mm²/s

Thermal Shock Resistance Index

4
3

Same in both: Specific Strength (UTS / density) 7 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 scaleSn63Pb37SbSn96Ag2.5Bi1Cu0.5

Manufacturing and finishing

CapabilitySn63Pb37SbSn96Ag2.5Bi1Cu0.5
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Sn63Pb37Sb vs Sn96Ag2.5Bi1Cu0.5 — frequently asked

Is Sn96Ag2.5Bi1Cu0.5 stronger than Sn63Pb37Sb?

Yes. Sn96Ag2.5Bi1Cu0.5 has a typical yield strength of 40 MPa (5.8 ksi) against 38 MPa (5.51 ksi) for Sn63Pb37Sb — about 5% more. Tensile strength is 52 MPa (7.54 ksi) vs 58 MPa (8.41 ksi).

Which is cheaper, Sn63Pb37Sb or Sn96Ag2.5Bi1Cu0.5?

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, Sn63Pb37Sb or Sn96Ag2.5Bi1Cu0.5?

Sn96Ag2.5Bi1Cu0.5, 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 Sn63Pb37Sb and Sn96Ag2.5Bi1Cu0.5 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.