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Solder & Low-Melting Alloy Pb58Sn40Sb2 vs Pb65Sn35

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Pb58Sn40Sb2 and Pb65Sn35 are both solder & low-melting alloy grades. Pb58Sn40Sb2 is the stronger of the two: yield strength 32 MPa (4.64 ksi) against 21 MPa (3.05 ksi) for Pb65Sn35, about 52% more; tensile strength follows at 48 MPa (6.96 ksi) vs 33 MPa (4.79 ksi). In exchange, Pb65Sn35 is the more ductile: elongation 55% versus 35% for Pb58Sn40Sb2, and Pb58Sn40Sb2 is harder (15 HB vs 12 HB). Pb58Sn40Sb2 runs hotter in service (110°C vs 100°C continuous).

Pb58Sn40Sb2Choose it when strength drives the design, or when the part sees heat.

Pb65Sn35Choose it when the part is bent, formed or impact-loaded.

Pb58Sn40Sb2 vs Pb65Sn35: properties

Pb58Sn40Sb2Pb65Sn35

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

27 GPa3.9 Msi
26 GPa3.8 Msi

Shear Modulus

9.8 GPa1.4 Msi
9.5 GPa1.4 Msi

Bulk Modulus

45 GPa6.5 Msi
43 GPa6.2 Msi

Tensile Strength (Ultimate)

48 MPa7 ksi
33 MPa4.8 ksi

Yield Strength (0.2% offset)

32 MPa4.6 ksi
21 MPa3 ksi

Elongation at Break

35%
55%

Shear Strength

36 MPa5.2 ksi
26 MPa3.8 ksi

Fatigue Strength (Endurance Limit)

14 MPa2 ksi
11 MPa1.6 ksi

Hardness, Brinell

15 HB
12 HB

Same in both: Poisson's Ratio 0.4

Physical

Density and transition temperatures.

Density

9.3 g/cm³0.34 lb/in³
9.5 g/cm³0.34 lb/in³

Melting Point (Solidus)

185°C365 °F
183°C361 °F

Liquidus Temperature

231°C448 °F
247°C477 °F

Thermal

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

Thermal Conductivity

43 W/m·K24.8 BTU/hr·ft·°F
44 W/m·K25.4 BTU/hr·ft·°F

Specific Heat Capacity

176 J/kg·K0.04 BTU/lb·°F
163 J/kg·K0.04 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

25.5 µm/m·K14.2 µin/in·°F
25 µm/m·K13.9 µin/in·°F

Latent Heat of Fusion

42 J/g18.1 BTU/lb
38 J/g16.3 BTU/lb

Max Service Temperature (continuous)

110°C230 °F
100°C212 °F

Same in both: Min Service Temperature -60°C-76 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

10.5 % IACS
9.5 % IACS

Electrical Resistivity

1.64×10⁻⁷ Ω·m6.46 µΩ·in
1.8×10⁻⁷ Ω·m7.09 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Galvanic Potential (seawater, vs SCE) -0.5 V · Corrosion Resistance 45 / 100

Manufacturability

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

Machinability

35 / 100
30 / 100

Castability

88 / 100
85 / 100

Brazeability / Solderability

90 / 100
88 / 100

Same in both: Weldability 20 / 100 · Formability (cold) 90 / 100 · Polishability 30 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

143 MJ/kg61,479 BTU/lb
128 MJ/kg55,030 BTU/lb

Embodied Carbon (primary production)

9.5 kg CO₂/kg
6.7 kg CO₂/kg

Embodied Water

320 L/kg38.3 gal/lb
300 L/kg35.9 gal/lb

Typical Recycled Content

40%
45%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

5 kN·m/kg
3 kN·m/kg

Specific Stiffness (E / density)

2.9 MN·m/kg
2.7 MN·m/kg

Modulus of Resilience

19 kJ/m³
8 kJ/m³

Thermal Diffusivity

26.3 mm²/s
28.4 mm²/s

Thermal Shock Resistance Index

3
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 scalePb65Sn35Pb58Sn40Sb2

Manufacturing and finishing

CapabilityPb58Sn40Sb2Pb65Sn35
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Pb58Sn40Sb2 vs Pb65Sn35 — frequently asked

Is Pb58Sn40Sb2 stronger than Pb65Sn35?

Yes. Pb58Sn40Sb2 has a typical yield strength of 32 MPa (4.64 ksi) against 21 MPa (3.05 ksi) for Pb65Sn35 — about 52% more. Tensile strength is 48 MPa (6.96 ksi) vs 33 MPa (4.79 ksi).

Which is cheaper, Pb58Sn40Sb2 or Pb65Sn35?

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, Pb58Sn40Sb2 or Pb65Sn35?

Pb58Sn40Sb2. Its machinability rates fair (35/100) against poor (30/100) for Pb65Sn35.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Pb58Sn40Sb2 and Pb65Sn35 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.