Solder & Low-Melting Alloy Pb85Sn15
ASTM B32 Sn15 · ISO 9453-121
Pb85Sn15 is a very lead-rich soft solder (ASTM B32 Sn15) in which reduced tin content lowers cost and widens the melting range to a 227–288 °C pasty interval.
Reference datasheet — Pb85Sn15 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
What is Pb85Sn15?
Pb85Sn15 is a very lead-rich soft solder (ASTM B32 Sn15) in which reduced tin content lowers cost and widens the melting range to a 227–288 °C pasty interval. It is used for metal filling, low-stress joints and general sheet metal work, and is available as bar, solid and cored wire, foil, preform and paste. Properties are modest — 24 MPa tensile, 12 MPa yield, 40 % elongation, 10 HB — with service limited to about 100 °C, and the low tin level means poorer wetting than Pb80Sn20 or Pb70Sn30. Lead content and RoHS restrictions confine it to non-electronic, non-food applications. Pb85Sn15 has a density of 10.5 g/cm³ (0.379 lb/in³), heavier than 84% of solder & low-melting alloy grades. It melts at 227°C (441 °F). Pb85Sn15 has a yield strength of 13 MPa (1.89 ksi) and a tensile strength of 25 MPa (3.63 ksi) — weaker than 87% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 23 GPa (3.34 Msi).
What is Pb85Sn15 used for?
- metal filling
- low-stress joints
- sheet metal work
Advantages
- Easy to machine — 75/100, better than 82% of solder & low-melting alloy grades
- Low embodied carbon — 4.5 kg CO₂/kg, better than 78% of solder & low-melting alloy grades
Limitations
- Low strength — 13 MPa (1.89 ksi), worse than 87% of solder & low-melting alloy grades
- Heavy — 10.5 g/cm³ (0.379 lb/in³), worse than 84% of solder & low-melting alloy grades
- Low stiffness — 23 GPa (3.34 Msi), worse than 75% of solder & low-melting alloy grades
Pb85Sn15 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Pb85Sn15 has a density of 10.5 g/cm³ (0.379 lb/in³), heavier than 84% of solder & low-melting alloy grades. It melts at 227°C (441 °F).
Mechanical11
Pb85Sn15 has a yield strength of 13 MPa (1.89 ksi) and a tensile strength of 25 MPa (3.63 ksi) — weaker than 87% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 23 GPa (3.34 Msi).
Thermal6
Pb85Sn15 is rated for continuous service to 100°C (212 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 60% of solder & low-melting alloy grades. Thermal expansion is 27 µm/m·K (15 µin/in·°F).
Electrical3
Pb85Sn15 conducts electricity at 8 % IACS, worse than 73% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (42/100), worse than 73% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of Pb85Sn15 takes about 53 MJ of energy and emits 4.5 kg of CO₂ — less than 79% of solder & low-melting alloy grades. Typical recycled content is 60%.
Manufacturability7
Pb85Sn15's machinability is very good (75/100, better than 82% of solder & low-melting alloy grades); weldability poor (20/100); formability excellent (95/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the solder & low-melting alloy family
Yield strength against density for every solder & low-melting alloy grade FabDigit runs. Pb85Sn15 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pb85Sn15
Is Pb85Sn15 easy to machine?
Machines only with very sharp, high-rake tools and flood lubricant — the alloy smears and loads cutters; scraping/filing with a 'cheese-grater' body file is the usual shaping method.
Can Pb85Sn15 be welded?
Not fusion welded; it is itself a filler — join with soldering iron, torch or dip pot at 300–370 °C using zinc-chloride/acid or activated rosin flux, and clean residues thoroughly.
Can Pb85Sn15 be formed, bent or molded?
Extremely plastic in the 227–288 °C pasty range, which is why it is wiped and paddled into place; cold rolls, extrudes and stamps easily at room temperature.
Pb85Sn15 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SnASTM B32 alloy grade Sn15 | 14.5 – 15.5 | 15 |
| Sbmax for non-antimonial grade | ≤ 0.2 | 0.05 |
| Bi | ≤ 0.25 | |
| Cu | ≤ 0.08 | |
| Ag | ≤ 0.02 | |
| Fe | ≤ 0.02 | |
| As | ≤ 0.03 | |
| Zn | ≤ 0.01 | |
| Al | ≤ 0.01 | |
| Cdcommonly restricted by purchase spec | ≤ 0 | |
| Pb | balance |
What surface finishes work on Pb85Sn15?
Filed and sanded flush then primed/painted; do not attempt anodizing or bright polishing — surface dulls to grey lead oxide, and lead dust/fume control plus RoHS restrictions apply.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Pb85Sn15 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B32 Sn15
- ISO
- 9453-121
How much does Pb85Sn15 cost?
Pb85Sn15 is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Pb85Sn15 — frequently asked
What is Pb85Sn15 used for?
Pb85Sn15 is typically used for metal filling, low-stress joints and sheet metal work. In short: wide 227–288 °C pasty range; low tin, low cost; poorer wetting than Sn20.
What is the yield strength of Pb85Sn15?
Pb85Sn15 has a typical yield strength of 13 MPa (1.89 ksi) and a tensile strength of 25 MPa (3.63 ksi) — weaker than 87% of solder & low-melting alloy grades.
Is Pb85Sn15 easy to machine?
Yes — machinability is rated very good (75/100, better than 82% of solder & low-melting alloy grades). Machines only with very sharp, high-rake tools and flood lubricant — the alloy smears and loads cutters; scraping/filing with a 'cheese-grater' body file is the usual shaping method.
Can Pb85Sn15 be welded?
Not readily — weldability is rated poor (20/100). Not fusion welded; it is itself a filler — join with soldering iron, torch or dip pot at 300–370 °C using zinc-chloride/acid or activated rosin flux, and clean residues thoroughly.
What surface finishes work on Pb85Sn15?
Filed and sanded flush then primed/painted; do not attempt anodizing or bright polishing — surface dulls to grey lead oxide, and lead dust/fume control plus RoHS restrictions apply.
Can Pb85Sn15 be formed, bent or molded?
Extremely plastic in the 227–288 °C pasty range, which is why it is wiped and paddled into place; cold rolls, extrudes and stamps easily at room temperature.
What is the maximum service temperature of Pb85Sn15?
Pb85Sn15 is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Pb85Sn15 cost?
Pb85Sn15 is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM B32 — Standard Specification for Solder Metal (alloy grade Sn15) — ASTM International (2020)
- GB/T 3131 (2020)
- ASM Handbook Vol.3: Alloy Phase Diagrams (Pb-Sn system) — ASM International (1992)
- ASM Handbook Vol.6: Welding, Brazing and Soldering — solder alloy properties — ASM International (1993)
- Sn/Pb solder alloy property tables — Indium Corporation / AIM Solder (2023)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.