Solder & Low-Melting Alloy Pb70Sn30 vs Pb85Sn15
Solder & Low-Melting Alloy · grade comparison
Solder & Low-Melting Alloy Pb70Sn30 and Pb85Sn15 are both solder & low-melting alloy grades. Pb70Sn30 is the stronger of the two: yield strength 22 MPa (3.19 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15, about 69% more; tensile strength follows at 38 MPa (5.51 ksi) vs 25 MPa (3.63 ksi). Pb70Sn30 is the more ductile: elongation 45% versus 40% for Pb85Sn15, and Pb70Sn30 is harder (12 HB vs 10 HB). Pb70Sn30 is lighter (9.7 g/cm³ vs 10.5 g/cm³ for Pb85Sn15) and Pb70Sn30 is stiffer (25 GPa vs 23 GPa). On the shop floor, Pb85Sn15 machines more easily (very good vs poor).
Pb70Sn30Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Pb85Sn15Choose it when the part is machined in volume.
Pb70Sn30 vs Pb85Sn15: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all solder & low-melting alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all solder & low-melting alloy grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Hardness, Brinell
Fatigue Strength (Endurance Limit)
Hardness, Vickers
Same in both: Bulk Modulus 42 GPa6.1 Msi · Poisson's Ratio 0.4
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Min Service Temperature
Same in both: Max Service Temperature (continuous) 100°C212 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Castability
Brazeability / Solderability
Polishability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | Pb70Sn30 | Pb85Sn15 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Pb70Sn30 vs Pb85Sn15 — frequently asked
Is Pb70Sn30 stronger than Pb85Sn15?
Yes. Pb70Sn30 has a typical yield strength of 22 MPa (3.19 ksi) against 13 MPa (1.89 ksi) for Pb85Sn15 — about 69% more. Tensile strength is 38 MPa (5.51 ksi) vs 25 MPa (3.63 ksi).
Which is cheaper, Pb70Sn30 or Pb85Sn15?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, Pb70Sn30 or Pb85Sn15?
Pb85Sn15. Its machinability rates very good (75/100) against poor (30/100) for Pb70Sn30; for welding the order is Pb85Sn15 first (poor, 20/100) then Pb70Sn30 (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Pb70Sn30 and Pb85Sn15 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.