Solder & Low-Melting Alloy Pb50Sn50Sb
ISO 9453-133
Pb50Sn50Sb is a 50/50 tin-lead solder modified with antimony, part of the Sn-Pb solder family, where the antimony addition raises strength and creep resistance over the plain alloy (34 MPa yield, 46 MPa tensile, 35% elongation, 15 HB).
Reference datasheet — Pb50Sn50Sb 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 Pb50Sn50Sb?
Pb50Sn50Sb is a 50/50 tin-lead solder modified with antimony, part of the Sn-Pb solder family, where the antimony addition raises strength and creep resistance over the plain alloy (34 MPa yield, 46 MPa tensile, 35% elongation, 15 HB). Engineers use it for plumbing and mechanically loaded sheet metal joints, and it is stocked as bar, solid and flux-cored wire, foil and paste. Service is limited to about 100 °C and the joint creeps under sustained load near that limit. It must not be used on zinc, galvanized steel or zinc die castings because antimony forms brittle Sb-Zn phases; plain 50/50 Sn-Pb is the alternative where antimony is not permitted. Pb50Sn50Sb has a density of 8.87 g/cm³ (0.32 lb/in³), heavier than 57% of solder & low-melting alloy grades. It melts at 183°C (361 °F). Pb50Sn50Sb has a yield strength of 36 MPa (5.22 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 83% of solder & low-melting alloy grades. Elongation at break is 35% and the elastic modulus is 30 GPa (4.35 Msi).
What is Pb50Sn50Sb used for?
- mechanically loaded soldered joints
- plumbing
- structural sheet metal joints
Advantages
- High strength — 36 MPa (5.22 ksi), better than 83% of solder & low-melting alloy grades
Limitations
- Needs corrosion protection — 35/100, worse than 94% of solder & low-melting alloy grades
- Difficult to weld — 10/100, worse than 94% of solder & low-melting alloy grades
Pb50Sn50Sb properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Pb50Sn50Sb has a density of 8.87 g/cm³ (0.32 lb/in³), heavier than 57% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Mechanical11
Pb50Sn50Sb has a yield strength of 36 MPa (5.22 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 83% of solder & low-melting alloy grades. Elongation at break is 35% and the elastic modulus is 30 GPa (4.35 Msi).
Thermal6
Pb50Sn50Sb is rated for continuous service to 100°C (212 °F). It conducts heat at 46 W/m·K (26.6 BTU/hr·ft·°F), better than 53% of solder & low-melting alloy grades. Thermal expansion is 24.5 µm/m·K (13.6 µin/in·°F).
Electrical3
Pb50Sn50Sb conducts electricity at 11 % IACS, better than 66% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (35/100), worse than 94% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of Pb50Sn50Sb takes about 170 MJ of energy and emits 9.5 kg of CO₂ — less than 56% of solder & low-melting alloy grades. Typical recycled content is 50%.
Manufacturability7
Pb50Sn50Sb's machinability is poor (25/100, worse than 82% of solder & low-melting alloy grades); weldability not recommended (10/100); formability excellent (90/100).
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. Pb50Sn50Sb is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pb50Sn50Sb
Is Pb50Sn50Sb easy to machine?
Very soft and gummy — use very sharp high-rake tools, high speed, low feed and generous lubricant; machining is rarely needed beyond trimming.
Can Pb50Sn50Sb be welded?
Not fusion welded; joints are made by soldering with rosin (electrical) or zinc-chloride/acid (plumbing) flux at 230–280 °C iron/pot temperature.
Can Pb50Sn50Sb be formed, bent or molded?
Cast to bar/ingot then extruded to wire or rolled to foil at room temperature; excellent extrudability, no annealing required.
Pb50Sn50Sb 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 |
|---|---|---|
| Sntin | 49.5 – 51 | 50 |
| Sbantimony addition — strengthens Sn phase; avoid on zinc/galvanized substrates | 0.2 – 0.5 | 0.35 |
| Biimpurity max | ≤ 0.25 | |
| Cuimpurity max | ≤ 0.08 | |
| Feimpurity max | ≤ 0.02 | |
| Asimpurity max | ≤ 0.03 | |
| Znimpurity max | ≤ 0.01 | |
| Alimpurity max | ≤ 0.01 | |
| Agimpurity max | ≤ 0.02 | |
| Pbbalance, nominally ~49.6 % | balance |
What surface finishes work on Pb50Sn50Sb?
Left as-solidified or lightly brushed; do not use on zinc, galvanized steel or zinc die castings (brittle Sb-Zn phases), and remove active flux residues by washing to prevent corrosion.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Pb50Sn50Sb in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ISO
- 9453-133
How much does Pb50Sn50Sb cost?
Pb50Sn50Sb is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Pb50Sn50Sb — frequently asked
What is Pb50Sn50Sb used for?
Pb50Sn50Sb is typically used for mechanically loaded soldered joints, plumbing and structural sheet metal joints. In short: antimony-strengthened 50/50 solder; better creep resistance than plain Sn-Pb; not for zinc or galvanized parts.
What is the yield strength of Pb50Sn50Sb?
Pb50Sn50Sb has a typical yield strength of 36 MPa (5.22 ksi) and a tensile strength of 48 MPa (6.96 ksi) — stronger than 83% of solder & low-melting alloy grades.
Is Pb50Sn50Sb easy to machine?
Not especially — machinability is rated poor (25/100, worse than 82% of solder & low-melting alloy grades). Very soft and gummy — use very sharp high-rake tools, high speed, low feed and generous lubricant; machining is rarely needed beyond trimming.
Can Pb50Sn50Sb be welded?
Not readily — weldability is rated not recommended (10/100). Not fusion welded; joints are made by soldering with rosin (electrical) or zinc-chloride/acid (plumbing) flux at 230–280 °C iron/pot temperature.
What surface finishes work on Pb50Sn50Sb?
Left as-solidified or lightly brushed; do not use on zinc, galvanized steel or zinc die castings (brittle Sb-Zn phases), and remove active flux residues by washing to prevent corrosion.
Can Pb50Sn50Sb be formed, bent or molded?
Cast to bar/ingot then extruded to wire or rolled to foil at room temperature; excellent extrudability, no annealing required.
What is the maximum service temperature of Pb50Sn50Sb?
Pb50Sn50Sb is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Pb50Sn50Sb cost?
Pb50Sn50Sb is a high-cost solder & low-melting alloy ($$$$), 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 (Tin-lead solders) — SAC / (2020)
- ASM Handbook Vol. 2 — Properties of Nonferrous Alloys (Sn, Pb and solder alloys) — ASM International (1990)
- ASM Specialty Handbook: Soldering and Brazing / ASM Handbook Vol. 6 — ASM International (1993)
- Database for Solder Properties with Emphasis on New Lead-Free Solders — NIST / Colorado School of Mines (2002)
- Sn-Pb solder alloy datasheets (bar, wire, paste, preforms) — 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.