Solder & Low-Melting Alloy Pb55Sn45
ISO 9453-113
Pb55Sn45 is a lead-rich tin-lead soft solder with a slightly wider pasty range than the 50/50 grade, used where a marginally higher liquidus is acceptable and slower freezing helps the joint be worked.
Reference datasheet — Pb55Sn45 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 Pb55Sn45?
Pb55Sn45 is a lead-rich tin-lead soft solder with a slightly wider pasty range than the 50/50 grade, used where a marginally higher liquidus is acceptable and slower freezing helps the joint be worked. It is stocked as bar, ingot, solid and flux-cored wire, foil, stamped preforms, powder and paste, covering both hand and machine soldering. Strength is low at 41 MPa tensile, 25 MPa yield, 50 % elongation and 13 HB, with a 100 °C service limit and time-dependent creep relaxation in loaded joints. As a lead-bearing alloy it is excluded from potable-water and RoHS applications; Pb50Sn50 is the closest substitute when a shorter freezing range is preferred. Pb55Sn45 has a density of 9.1 g/cm³ (0.329 lb/in³), heavier than 60% of solder & low-melting alloy grades. It melts at 183°C (361 °F). Pb55Sn45 has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 41 MPa (5.95 ksi) — weaker than 61% of solder & low-melting alloy grades. Elongation at break is 50% and the elastic modulus is 28 GPa (4.06 Msi).
What is Pb55Sn45 used for?
- general soft soldering
- sheet metal joining
- wiping joints
Advantages
- Ductile — tolerates forming and impact — 50%, better than 92% of solder & low-melting alloy grades
Limitations
- Hard to polish — 20/100, worse than 88% of solder & low-melting alloy grades
Pb55Sn45 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Pb55Sn45 has a density of 9.1 g/cm³ (0.329 lb/in³), heavier than 60% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Mechanical10
Pb55Sn45 has a yield strength of 25 MPa (3.63 ksi) and a tensile strength of 41 MPa (5.95 ksi) — weaker than 61% of solder & low-melting alloy grades. Elongation at break is 50% and the elastic modulus is 28 GPa (4.06 Msi).
Thermal6
Pb55Sn45 is rated for continuous service to 100°C (212 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), worse than 52% of solder & low-melting alloy grades. Thermal expansion is 25 µm/m·K (13.9 µin/in·°F).
Electrical3
Pb55Sn45 conducts electricity at 10.5 % IACS, better than 60% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is fair (40/100), worse than 82% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of Pb55Sn45 takes about 126 MJ of energy and emits 8.1 kg of CO₂ — less than 64% of solder & low-melting alloy grades. Typical recycled content is 35%.
Manufacturability6
Pb55Sn45's machinability is fair (35/100, better than 58% of solder & low-melting alloy grades); 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. Pb55Sn45 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Pb55Sn45
Is Pb55Sn45 easy to machine?
Extremely soft and prone to sticking to the tool — use sharp high-rake tooling, high speed with low feed, and kerosene or soap-solution lubricant. In practice shearing, blanking or casting to size replaces cutting.
Can Pb55Sn45 be welded?
The alloy is a filler metal, not a fusion-welded structural material. Hold iron or solder-pot temperature at 250–280 °C to avoid excess dross and copper dissolution from overheating.
Can Pb55Sn45 be formed, bent or molded?
It recrystallises at room temperature, so cold drawing, foil rolling and preform stamping are all straightforward; formed parts will creep and relax over time.
Pb55Sn45 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 Sn45 | 44 – 46 | 45 |
| Sbimpurity limit; low-antimony grade is tighter | ≤ 0.5 | 0.1 |
| Bi | ≤ 0.25 | |
| Cu | ≤ 0.08 | |
| Ag | ≤ 0.02 | |
| Fe | ≤ 0.02 | |
| As | ≤ 0.03 | |
| Zn | ≤ 0.01 | |
| Al | ≤ 0.01 | |
| Cd | ≤ 0 | |
| Pbbalance, about 55% | balance |
What surface finishes work on Pb55Sn45?
Remove acidic or activated flux residues after soldering (isopropanol for rosin types, water for water-soluble). The surface darkens naturally; anodizing does not apply, but tin plating or conformal coating can be used for protection.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy Pb55Sn45 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ISO
- 9453-113
How much does Pb55Sn45 cost?
Pb55Sn45 is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Pb55Sn45 — frequently asked
What is Pb55Sn45 used for?
Pb55Sn45 is typically used for general soft soldering, sheet metal joining and wiping joints. In short: lead-rich 45 % tin solder; wider pasty range than 50/50; low-cost general soft solder.
What is the yield strength of Pb55Sn45?
Pb55Sn45 has a typical yield strength of 25 MPa (3.63 ksi) and a tensile strength of 41 MPa (5.95 ksi) — weaker than 61% of solder & low-melting alloy grades.
Is Pb55Sn45 easy to machine?
Not especially — machinability is rated fair (35/100, better than 58% of solder & low-melting alloy grades). Extremely soft and prone to sticking to the tool — use sharp high-rake tooling, high speed with low feed, and kerosene or soap-solution lubricant. In practice shearing, blanking or casting to size replaces cutting.
Can Pb55Sn45 be welded?
The alloy is a filler metal, not a fusion-welded structural material. Hold iron or solder-pot temperature at 250–280 °C to avoid excess dross and copper dissolution from overheating.
What surface finishes work on Pb55Sn45?
Remove acidic or activated flux residues after soldering (isopropanol for rosin types, water for water-soluble). The surface darkens naturally; anodizing does not apply, but tin plating or conformal coating can be used for protection.
Can Pb55Sn45 be formed, bent or molded?
It recrystallises at room temperature, so cold drawing, foil rolling and preform stamping are all straightforward; formed parts will creep and relax over time.
What is the maximum service temperature of Pb55Sn45?
Pb55Sn45 is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Pb55Sn45 cost?
Pb55Sn45 is a high-cost solder & low-melting alloy ($$$$), 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)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials (Solders) — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
- Sn-Pb binary phase diagram data — ASM Alloy Phase Diagram Database (2016)
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.