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Solder & Low-Melting Alloy Sn63Pb37Sb vs Sn95Cu4Ag1

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Sn63Pb37Sb and Sn95Cu4Ag1 are both solder & low-melting alloy grades. Sn63Pb37Sb is the stronger of the two: yield strength 38 MPa (5.51 ksi) against 32 MPa (4.64 ksi) for Sn95Cu4Ag1, about 19% more; tensile strength follows at 58 MPa (8.41 ksi) vs 48 MPa (6.96 ksi). Sn63Pb37Sb is the more ductile: elongation 32% versus 25% for Sn95Cu4Ag1, and Sn95Cu4Ag1 is harder (18 HB vs 16 HB). Sn95Cu4Ag1 is lighter (7.35 g/cm³ vs 8.4 g/cm³ for Sn63Pb37Sb) and Sn95Cu4Ag1 is stiffer (48 GPa vs 32 GPa). On the shop floor, Sn95Cu4Ag1 machines more easily (30 vs 20 out of 100).

Sn63Pb37SbChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

Sn95Cu4Ag1Choose it when weight is the constraint, or when the part sees heat.

Sn63Pb37Sb vs Sn95Cu4Ag1: properties

Sn63Pb37SbSn95Cu4Ag1

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
55 GPa8 Msi

Poisson's Ratio

0.4
0.36

Tensile Strength (Ultimate)

58 MPa8.4 ksi
48 MPa7 ksi

Yield Strength (0.2% offset)

38 MPa5.5 ksi
32 MPa4.6 ksi

Elongation at Break

32%
25%

Shear Strength

38 MPa5.5 ksi
30 MPa4.4 ksi

Fatigue Strength (Endurance Limit)

15 MPa2.2 ksi
20 MPa2.9 ksi

Hardness, Brinell

16 HB
18 HB

Compressive Strength

—
45 MPa6.5 ksi

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

183°C361 °F
217°C423 °F

Liquidus Temperature

185°C365 °F
330°C626 °F

Thermal

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

Thermal Conductivity

50 W/m·K28.9 BTU/hr·ft·°F
60 W/m·K34.7 BTU/hr·ft·°F

Specific Heat Capacity

170 J/kg·K0.04 BTU/lb·°F
230 J/kg·K0.05 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

24.5 µm/m·K13.6 µin/in·°F
22.5 µm/m·K12.5 µin/in·°F

Latent Heat of Fusion

42 J/g18.1 BTU/lb
60 J/g25.8 BTU/lb

Max Service Temperature (continuous)

100°C212 °F
150°C302 °F

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

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 11.5 % IACS · Electrical Resistivity 1.5×10⁻⁷ Ω·m5.91 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
30 / 100

Castability

95 / 100
80 / 100

Brazeability / Solderability

100 / 100
90 / 100

Same in both: Weldability 20 / 100 · Formability (cold) 90 / 100 · Polishability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

210 MJ/kg90,284 BTU/lb
330 MJ/kg141,875 BTU/lb

Embodied Carbon (primary production)

11 kg CO₂/kg
17 kg CO₂/kg

Embodied Water

320 L/kg38.3 gal/lb
250 L/kg30 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
11 kJ/m³

Thermal Diffusivity

35 mm²/s
35.5 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 scaleSn63Pb37SbSn95Cu4Ag1

Manufacturing and finishing

CapabilitySn63Pb37SbSn95Cu4Ag1
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Sn63Pb37Sb vs Sn95Cu4Ag1 — frequently asked

Is Sn63Pb37Sb stronger than Sn95Cu4Ag1?

Yes. Sn63Pb37Sb has a typical yield strength of 38 MPa (5.51 ksi) against 32 MPa (4.64 ksi) for Sn95Cu4Ag1 — about 19% more. Tensile strength is 58 MPa (8.41 ksi) vs 48 MPa (6.96 ksi).

Which is cheaper, Sn63Pb37Sb or Sn95Cu4Ag1?

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 Sn95Cu4Ag1?

Sn95Cu4Ag1, by a small margin. Both rate poor for machinability — 30/100 against 20/100 for Sn63Pb37Sb.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Sn63Pb37Sb and Sn95Cu4Ag1 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.