Solder & Low-Melting Alloy Pb49Sn48Bi3
ISO 9453-142
Pb49Sn48Bi3 is a bismuth-modified tin-lead solder whose 3% bismuth slightly depresses the melting point relative to plain 50/50, giving 45 MPa tensile strength, 40% elongation and 14 HB.
Reference datasheet — Pb49Sn48Bi3 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 Pb49Sn48Bi3?
Pb49Sn48Bi3 is a bismuth-modified tin-lead solder whose 3% bismuth slightly depresses the melting point relative to plain 50/50, giving 45 MPa tensile strength, 40% elongation and 14 HB. It is used for heat-sensitive assemblies and low-temperature joint repair, and is supplied as bar, wire, cored wire, ribbon, preform, paste and pre-made joints. Service is limited to about 100 °C, overheating above 320 °C causes oxide dross and bismuth segregation, and the alloy is lead-bearing so RoHS/REACH controls apply. Plain 50/50 Sn-Pb is the alternative where the lower melting point is not needed. Pb49Sn48Bi3 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 59% of solder & low-melting alloy grades. It melts at 178°C (352 °F). Pb49Sn48Bi3 has a yield strength of 28 MPa (4.06 ksi) and a tensile strength of 45 MPa (6.53 ksi) — stronger than 51% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 30 GPa (4.35 Msi).
What is Pb49Sn48Bi3 used for?
- heat-sensitive component soldering
- low-temperature joint repair
- specialty electronics soldering
Limitations
- Needs corrosion protection — 35/100, worse than 94% of solder & low-melting alloy grades
- Hard to polish — 20/100, worse than 88% of solder & low-melting alloy grades
Pb49Sn48Bi3 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Pb49Sn48Bi3 has a density of 8.9 g/cm³ (0.322 lb/in³), heavier than 59% of solder & low-melting alloy grades. It melts at 178°C (352 °F).
Mechanical11
Pb49Sn48Bi3 has a yield strength of 28 MPa (4.06 ksi) and a tensile strength of 45 MPa (6.53 ksi) — stronger than 51% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 30 GPa (4.35 Msi).
Thermal6
Pb49Sn48Bi3 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 µm/m·K (13.3 µin/in·°F).
Electrical3
Pb49Sn48Bi3 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 Pb49Sn48Bi3 takes about 135 MJ of energy and emits 8.5 kg of CO₂ — less than 62% of solder & low-melting alloy grades. Typical recycled content is 35%.
Manufacturability7
Pb49Sn48Bi3's machinability is poor (25/100, worse than 82% of solder & low-melting alloy grades); weldability poor (20/100); 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. Pb49Sn48Bi3 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pb49Sn48Bi3
Is Pb49Sn48Bi3 easy to machine?
Very soft and prone to sticking to the tool — use sharp, high-rake tooling at low speed with high feed and kerosene or alcohol lubricant. Parts are normally blanked or extruded to shape rather than cut.
Can Pb49Sn48Bi3 be welded?
Not used as a fusion-welded base metal. When re-melting, avoid overheating above 320 °C to limit oxide dross and bismuth segregation.
Can Pb49Sn48Bi3 be formed, bent or molded?
Cold workability is excellent: the alloy extrudes to wire, rolls to foil and stamps into preforms with no intermediate annealing, since room temperature is already above its recrystallization temperature.
Pb49Sn48Bi3 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 | 47 – 49 | 48 |
| Bilowers the solidus | 2.5 – 3.5 | 3 |
| Sbimpurity limit | ≤ 0.2 | |
| Cuimpurity limit | ≤ 0.08 | |
| Agimpurity limit | ≤ 0.05 | |
| Feimpurity limit | ≤ 0.02 | |
| Asimpurity limit | ≤ 0.03 | |
| Znimpurity limit; affects wetting | ≤ 0 | |
| Alimpurity limit; affects wetting | ≤ 0.01 | |
| Cdimpurity limit | ≤ 0 | |
| Pb | balance |
What surface finishes work on Pb49Sn48Bi3?
Remove active flux residues after soldering (isopropanol or saponifier for rosin types; no-clean types per process). The surface cannot be anodized, and long storage forms a dark grey oxide film that does not affect re-melt wetting.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Pb49Sn48Bi3 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ISO
- 9453-142
How much does Pb49Sn48Bi3 cost?
Pb49Sn48Bi3 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.
Pb49Sn48Bi3 — frequently asked
What is Pb49Sn48Bi3 used for?
Pb49Sn48Bi3 is typically used for heat-sensitive component soldering, low-temperature joint repair and specialty electronics soldering. In short: lower melting than 50/50; bismuth-modified Sn-Pb solder; for heat-sensitive assemblies.
What is the yield strength of Pb49Sn48Bi3?
Pb49Sn48Bi3 has a typical yield strength of 28 MPa (4.06 ksi) and a tensile strength of 45 MPa (6.53 ksi) — stronger than 51% of solder & low-melting alloy grades.
Is Pb49Sn48Bi3 easy to machine?
Not especially — machinability is rated poor (25/100, worse than 82% of solder & low-melting alloy grades). Very soft and prone to sticking to the tool — use sharp, high-rake tooling at low speed with high feed and kerosene or alcohol lubricant. Parts are normally blanked or extruded to shape rather than cut.
Can Pb49Sn48Bi3 be welded?
Not readily — weldability is rated poor (20/100). Not used as a fusion-welded base metal. When re-melting, avoid overheating above 320 °C to limit oxide dross and bismuth segregation.
What surface finishes work on Pb49Sn48Bi3?
Remove active flux residues after soldering (isopropanol or saponifier for rosin types; no-clean types per process). The surface cannot be anodized, and long storage forms a dark grey oxide film that does not affect re-melt wetting.
Can Pb49Sn48Bi3 be formed, bent or molded?
Cold workability is excellent: the alloy extrudes to wire, rolls to foil and stamps into preforms with no intermediate annealing, since room temperature is already above its recrystallization temperature.
What is the maximum service temperature of Pb49Sn48Bi3?
Pb49Sn48Bi3 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 Pb49Sn48Bi3 cost?
Pb49Sn48Bi3 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
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys (Solders) — ASM International (1990)
- ASTM B32 — Standard Specification for Solder Metal — ASTM (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys — IPC/JEDEC (2017)
- GB/T 3131 (2020)
- Specialty solder alloy melting-range tables (Sn/Pb/Bi) — 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.