Solder & Low-Melting Alloy Pb50Sn50
ASTM B32 Sn50 · GB HLSnPb50-50 · ISO 9453-111
Pb50Sn50 (B32 Sn50, HLSnPb50-50) is a tin-lead soft solder with a pasty solidification range of 183–216 °C, historically the most common general-purpose plumbing and sheet-metal solder before lead restrictions.
Reference datasheet — Pb50Sn50 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 Pb50Sn50?
Pb50Sn50 (B32 Sn50, HLSnPb50-50) is a tin-lead soft solder with a pasty solidification range of 183–216 °C, historically the most common general-purpose plumbing and sheet-metal solder before lead restrictions. It is chosen where the wide freezing range allows a joint to be wiped and shaped, and is supplied as bar, solid wire, rosin- and acid-cored wire, paste and foil. Mechanical capability is low — 45 MPa tensile, 28 MPa yield, 50 % elongation, 14 HB — with a maximum service temperature of 100 °C and creep under sustained load. Lead content rules out potable-water and RoHS work; use Sn63Pb37 for eutectic electronic joints or a lead-free Sn-Ag-Cu solder instead. Pb50Sn50 has a density of 8.85 g/cm³ (0.32 lb/in³), heavier than 55% of solder & low-melting alloy grades. It melts at 183°C (361 °F). Pb50Sn50 has a yield strength of 27 MPa (3.92 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 51% of solder & low-melting alloy grades. Elongation at break is 55% and the elastic modulus is 23 GPa (3.34 Msi).
What is Pb50Sn50 used for?
- copper pipe joints
- radiator repair
- sheet metal seaming
- general wiping solder
Advantages
- Ductile — tolerates forming and impact — 55%, better than 96% of solder & low-melting alloy grades
Limitations
- Hard to polish — 20/100, worse than 88% of solder & low-melting alloy grades
- Low stiffness — 23 GPa (3.34 Msi), worse than 75% of solder & low-melting alloy grades
Pb50Sn50 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Pb50Sn50 has a density of 8.85 g/cm³ (0.32 lb/in³), heavier than 55% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Mechanical11
Pb50Sn50 has a yield strength of 27 MPa (3.92 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 51% of solder & low-melting alloy grades. Elongation at break is 55% and the elastic modulus is 23 GPa (3.34 Msi).
Thermal6
Pb50Sn50 is rated for continuous service to 100°C (212 °F). It conducts heat at 50 W/m·K (28.9 BTU/hr·ft·°F), better than 63% of solder & low-melting alloy grades. Thermal expansion is 24.5 µm/m·K (13.6 µin/in·°F).
Electrical3
Pb50Sn50 conducts electricity at 10.9 % IACS, better than 63% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 52% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of Pb50Sn50 takes about 160 MJ of energy and emits 10.5 kg of CO₂ — less than 58% of solder & low-melting alloy grades. Typical recycled content is 45%.
Manufacturability8
Pb50Sn50's machinability is poor (30/100, worse than 60% of solder & low-melting alloy grades); weldability poor (15/100); 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. Pb50Sn50 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pb50Sn50
Is Pb50Sn50 easy to machine?
Very soft and gummy — use sharp positive-rake tools, high rake angles, flood coolant and slow feeds; avoid dry cutting and capture lead-bearing chips.
Can Pb50Sn50 be welded?
Not arc welded; joints are made by re-melting with a torch, iron or solder pot at 230–280 °C using zinc-chloride or rosin flux to fully wet copper, brass and tinned steel.
Can Pb50Sn50 be formed, bent or molded?
Extrudes into wire and rolls into foil at room temperature; the 183–216 °C pasty range lets plumbers wipe and shape the joint before full solidification.
Pb50Sn50 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 grade Sn50 | 49.5 – 50.5 | 50 |
| Sb0.20–0.50 % in antimonial variants (Sn50A/B) | ≤ 0.12 | 0.05 |
| Bi | ≤ 0.25 | |
| Cu | ≤ 0.08 | |
| Ag | ≤ 0.02 | |
| Fe | ≤ 0.02 | |
| Zn | ≤ 0.01 | |
| Al | ≤ 0.01 | |
| As | ≤ 0.03 | |
| Cd | ≤ 0 | |
| Pbremainder, nominally 50 % | balance |
What surface finishes work on Pb50Sn50?
Left as-soldered or lightly wire-brushed; flux residues should be washed off (water for acid flux, solvent for rosin), and the surface can be tinned or painted but not anodized.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Pb50Sn50 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- B32 Sn50
- ISO
- 9453-111
- GB (China)
- HLSnPb50-50
How much does Pb50Sn50 cost?
Pb50Sn50 is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Pb50Sn50 — frequently asked
What is Pb50Sn50 used for?
Pb50Sn50 is typically used for copper pipe joints, radiator repair, sheet metal seaming and general wiping solder. In short: classic 50/50 plumbing solder; wide pasty wiping range; not for potable water.
What is the yield strength of Pb50Sn50?
Pb50Sn50 has a typical yield strength of 27 MPa (3.92 ksi) and a tensile strength of 42 MPa (6.09 ksi) — weaker than 51% of solder & low-melting alloy grades.
Is Pb50Sn50 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 60% of solder & low-melting alloy grades). Very soft and gummy — use sharp positive-rake tools, high rake angles, flood coolant and slow feeds; avoid dry cutting and capture lead-bearing chips.
Can Pb50Sn50 be welded?
Not readily — weldability is rated poor (15/100). Not arc welded; joints are made by re-melting with a torch, iron or solder pot at 230–280 °C using zinc-chloride or rosin flux to fully wet copper, brass and tinned steel.
What surface finishes work on Pb50Sn50?
Left as-soldered or lightly wire-brushed; flux residues should be washed off (water for acid flux, solvent for rosin), and the surface can be tinned or painted but not anodized.
Can Pb50Sn50 be formed, bent or molded?
Extrudes into wire and rolls into foil at room temperature; the 183–216 °C pasty range lets plumbers wipe and shape the joint before full solidification.
What is the maximum service temperature of Pb50Sn50?
Pb50Sn50 is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Pb50Sn50 cost?
Pb50Sn50 is a high-cost solder & low-melting alloy ($$$$), 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 — ASTM International (2020)
- GB/T 3131 (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys — IPC (2013)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering (Soldering section) — ASM International (1993)
- ASM Handbook Vol.3 — Alloy Phase Diagrams (Sn-Pb system) — ASM International (1992)
- NIST Database of Solder Properties with Emphasis on New Lead-Free Solders — NIST/Colorado School of Mines (2002)
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.