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Solder & Low-Melting Alloy Sn60Pb40Sb vs Sn97Cu3

Solder & Low-Melting Alloy · grade comparison

Solder & Low-Melting Alloy Sn60Pb40Sb and Sn97Cu3 are both solder & low-melting alloy grades. Sn60Pb40Sb is the stronger of the two: yield strength 32 MPa (4.64 ksi) against 25 MPa (3.63 ksi) for Sn97Cu3, about 28% more; tensile strength follows at 52 MPa (7.54 ksi) vs 35 MPa (5.08 ksi). Sn97Cu3 is lighter (7.33 g/cm³ vs 8.5 g/cm³ for Sn60Pb40Sb) and Sn97Cu3 is stiffer (45 GPa vs 31 GPa). On the shop floor, Sn97Cu3 welds better (poor vs not recommended).

Sn60Pb40SbChoose it when strength drives the design.

Sn97Cu3Choose it when weight is the constraint, or when the part sees heat.

Sn60Pb40Sb vs Sn97Cu3: properties

Sn60Pb40SbSn97Cu3

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

31 GPa4.5 Msi
45 GPa6.5 Msi

Shear Modulus

11.5 GPa1.7 Msi
17 GPa2.5 Msi

Bulk Modulus

42 GPa6.1 Msi
55 GPa8 Msi

Poisson's Ratio

0.38
0.36

Tensile Strength (Ultimate)

52 MPa7.5 ksi
35 MPa5.1 ksi

Yield Strength (0.2% offset)

32 MPa4.6 ksi
25 MPa3.6 ksi

Shear Strength

38 MPa5.5 ksi
27 MPa3.9 ksi

Charpy V-Notch Impact (RT)

6 J4.4 ft·lbf
—

Hardness, Vickers

16 HV
—

Same in both: Elongation at Break 35% · Fatigue Strength (Endurance Limit) 15 MPa2.2 ksi · Hardness, Brinell 15 HB

Physical

Density and transition temperatures.

Density

8.5 g/cm³0.31 lb/in³
7.33 g/cm³0.26 lb/in³

Melting Point (Solidus)

183°C361 °F
227°C441 °F

Liquidus Temperature

190°C374 °F
310°C590 °F

Thermal

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

Thermal Conductivity

50 W/m·K28.9 BTU/hr·ft·°F
65 W/m·K37.6 BTU/hr·ft·°F

Specific Heat Capacity

176 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
23 µm/m·K12.8 µin/in·°F

Latent Heat of Fusion

43 J/g18.5 BTU/lb
60 J/g25.8 BTU/lb

Max Service Temperature (continuous)

110°C230 °F
125°C257 °F

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

Electrical

Conductivity and insulation.

Electrical Conductivity

11.5 % IACS
13.5 % IACS

Electrical Resistivity

1.5×10⁻⁷ Ω·m5.91 µΩ·in
1.28×10⁻⁷ Ω·m5.04 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
50 / 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

35 / 100
30 / 100

Weldability

10 / 100
20 / 100

Formability (cold)

85 / 100
90 / 100

Castability

95 / 100
80 / 100

Brazeability / Solderability

92 / 100
80 / 100

Same in both: Polishability 25 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

190 MJ/kg81,685 BTU/lb
300 MJ/kg128,977 BTU/lb

Embodied Carbon (primary production)

10.3 kg CO₂/kg
18 kg CO₂/kg

Embodied Water

320 L/kg38.3 gal/lb
350 L/kg41.9 gal/lb

Typical Recycled Content

35%
30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

6 kN·m/kg
5 kN·m/kg

Specific Stiffness (E / density)

3.6 MN·m/kg
6.1 MN·m/kg

Modulus of Resilience

17 kJ/m³
7 kJ/m³

Thermal Diffusivity

33.4 mm²/s
38.6 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 scaleSn60Pb40SbSn97Cu3

Manufacturing and finishing

CapabilitySn60Pb40SbSn97Cu3
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Sn60Pb40Sb vs Sn97Cu3 — frequently asked

Is Sn60Pb40Sb stronger than Sn97Cu3?

Yes. Sn60Pb40Sb has a typical yield strength of 32 MPa (4.64 ksi) against 25 MPa (3.63 ksi) for Sn97Cu3 — about 28% more. Tensile strength is 52 MPa (7.54 ksi) vs 35 MPa (5.08 ksi).

Which is cheaper, Sn60Pb40Sb or Sn97Cu3?

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, Sn60Pb40Sb or Sn97Cu3?

Sn60Pb40Sb. Its machinability rates fair (35/100) against poor (30/100) for Sn97Cu3; for welding the order is Sn97Cu3 first (poor, 20/100) then Sn60Pb40Sb (not recommended, 10/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in Sn60Pb40Sb and Sn97Cu3 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.