Solder & Low-Melting Alloy Bi50Pb25Sn25 vs Bi58Sn42
Solder & Low-Melting Alloy · grade comparison
Solder & Low-Melting Alloy Bi50Pb25Sn25 and Bi58Sn42 are both solder & low-melting alloy grades. Bi58Sn42 is the stronger of the two: yield strength 42 MPa (6.09 ksi) against 18 MPa (2.61 ksi) for Bi50Pb25Sn25, about 133% more; tensile strength follows at 65 MPa (9.43 ksi) vs 30 MPa (4.35 ksi). Bi58Sn42 is the more ductile: elongation 40% versus 35% for Bi50Pb25Sn25, and Bi58Sn42 is harder (22 HB vs 11 HB). Bi58Sn42 is lighter (8.56 g/cm³ vs 9.7 g/cm³ for Bi50Pb25Sn25) and Bi58Sn42 is stiffer (42 GPa vs 25 GPa). On the shop floor, Bi50Pb25Sn25 machines more easily (fair vs poor) and Bi58Sn42 welds better (poor vs not recommended).
Bi50Pb25Sn25Choose it when the part is machined in volume.
Bi58Sn42Choose it when strength drives the design, or when the part is bent, formed or impact-loaded.
Bi50Pb25Sn25 vs Bi58Sn42: 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
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Hardness, Brinell
Fatigue Strength (Endurance Limit)
Hardness, Vickers
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
Thermal Expansion (CTE, 20–100 °C)
Latent Heat of Fusion
Max Service Temperature (continuous)
Min Service Temperature
Same in both: Specific Heat Capacity 167 J/kg·K0.04 BTU/lb·°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
Machinability Rating (AISI 1212 = 100 %)
Weldability
Castability
Polishability
Same in both: Formability (cold) 60 / 100 · Brazeability / Solderability 95 / 100
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 | Bi50Pb25Sn25 | Bi58Sn42 |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$$$ High | $$$$ High |
| Min. machined wall | — | — |
| Best machined surface | — | — |
Bi50Pb25Sn25 vs Bi58Sn42 — frequently asked
Is Bi58Sn42 stronger than Bi50Pb25Sn25?
Yes. Bi58Sn42 has a typical yield strength of 42 MPa (6.09 ksi) against 18 MPa (2.61 ksi) for Bi50Pb25Sn25 — about 133% more. Tensile strength is 65 MPa (9.43 ksi) vs 30 MPa (4.35 ksi).
Which is cheaper, Bi50Pb25Sn25 or Bi58Sn42?
Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.
Which is easier to machine, Bi50Pb25Sn25 or Bi58Sn42?
Bi50Pb25Sn25. Its machinability rates fair (40/100) against poor (30/100) for Bi58Sn42; for welding the order is Bi58Sn42 first (poor, 20/100) then Bi50Pb25Sn25 (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Bi50Pb25Sn25 and Bi58Sn42 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.