Solder & Low-Melting Alloy Sn63Pb37E
Sn63Pb37E is the extra-refined ('E') version of the eutectic 63/37 tin-lead solder, specified by ISO 9453 with tighter limits on trace impurities such as Bi, Sb, Cu, Fe, Zn and Al.
Reference datasheet — Sn63Pb37E 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 Sn63Pb37E?
Sn63Pb37E is the extra-refined ('E') version of the eutectic 63/37 tin-lead solder, specified by ISO 9453 with tighter limits on trace impurities such as Bi, Sb, Cu, Fe, Zn and Al. It melts at the same 183 °C eutectic point and is used where trace-element control affects joint reliability, offering 46 MPa tensile strength, 30 MPa yield strength, 40 % elongation and 17 HB; forms include bar, solid and cored wire, T3 and T4 paste, powder, preforms, ribbon and plating anodes. It costs more than general-purpose 63/37 and, being leaded, is barred from RoHS-compliant products; use standard Sn63Pb37 for non-critical work. Sn63Pb37E has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 57% of solder & low-melting alloy grades. It melts at 183°C (361 °F). Sn63Pb37E has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 46 MPa (6.67 ksi) — stronger than 61% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 30 GPa (4.35 Msi).
What is Sn63Pb37E used for?
- high-reliability electronics soldering
- aerospace/military PCB assembly
- fine-pitch component soldering
Limitations
- Difficult to machine — 20/100, worse than 94% of solder & low-melting alloy grades
Sn63Pb37E properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
Sn63Pb37E has a density of 8.4 g/cm³ (0.303 lb/in³), lighter than 57% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Mechanical11
Sn63Pb37E has a yield strength of 30 MPa (4.35 ksi) and a tensile strength of 46 MPa (6.67 ksi) — stronger than 61% of solder & low-melting alloy grades. Elongation at break is 40% and the elastic modulus is 30 GPa (4.35 Msi).
Thermal6
Sn63Pb37E 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 25 µm/m·K (13.9 µin/in·°F).
Electrical3
Sn63Pb37E conducts electricity at 11.5 % IACS, better than 71% 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 Sn63Pb37E takes about 210 MJ of energy and emits 11.5 kg of CO₂ — more than 57% of solder & low-melting alloy grades. Typical recycled content is 35%.
Manufacturability6
Sn63Pb37E's machinability is poor (20/100, worse than 94% of solder & low-melting alloy grades); 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. Sn63Pb37E is highlighted; hover a dot for its name, or open the interactive family chart.
Working with Sn63Pb37E
Is Sn63Pb37E easy to machine?
Machines only with very sharp, high-rake tools, generous lubricant and low speed — the alloy smears, gums up flutes and is normally cast, stamped or extruded to shape instead.
Can Sn63Pb37E be welded?
Not fusion-welded; joints are made by soldering itself — reflow, wave, iron or vapour-phase at 205–235 °C peak with rosin/no-clean flux.
Can Sn63Pb37E be formed, bent or molded?
Eutectic freezing gives excellent castability and fluidity; extrudes into wire and rolls into foil at room temperature but creeps and recrystallises, so stored preforms should be used within their shelf life.
Sn63Pb37E 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 |
|---|---|---|
| Sneutectic composition | 62.5 – 63.5 | 63 |
| SbE-grade (extra-refined) impurity limit | ≤ 0.05 | |
| BiE-grade limit | ≤ 0.05 | |
| CuE-grade limit | ≤ 0.03 | |
| AgE-grade limit | ≤ 0.02 | |
| FeE-grade limit | ≤ 0.02 | |
| AsE-grade limit | ≤ 0.03 | |
| Zncritical — degrades wetting | ≤ 0 | |
| Alcritical — degrades wetting | ≤ 0 | |
| CdE-grade limit | ≤ 0 | |
| Inresidual | ≤ 0.1 | |
| Niresidual | ≤ 0.01 | |
| Auresidual | ≤ 0.05 | |
| Pb | balance |
What surface finishes work on Sn63Pb37E?
Surfaces are used as-reflowed or fused/hot-air levelled; do not anodize or paint — clean flux residues with saponifier or IPA and avoid abrasive polishing, which embeds grit in the soft metal.
How much does Sn63Pb37E cost?
Sn63Pb37E is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sn63Pb37E — frequently asked
What is Sn63Pb37E used for?
Sn63Pb37E is typically used for high-reliability electronics soldering, aerospace/military PCB assembly and fine-pitch component soldering. In short: extra-refined eutectic 63/37; controlled trace impurities; for high-reliability assembly.
What is the yield strength of Sn63Pb37E?
Sn63Pb37E has a typical yield strength of 30 MPa (4.35 ksi) and a tensile strength of 46 MPa (6.67 ksi) — stronger than 61% of solder & low-melting alloy grades.
Is Sn63Pb37E easy to machine?
Not especially — machinability is rated poor (20/100, worse than 94% of solder & low-melting alloy grades). Machines only with very sharp, high-rake tools, generous lubricant and low speed — the alloy smears, gums up flutes and is normally cast, stamped or extruded to shape instead.
Can Sn63Pb37E be welded?
Not fusion-welded; joints are made by soldering itself — reflow, wave, iron or vapour-phase at 205–235 °C peak with rosin/no-clean flux.
What surface finishes work on Sn63Pb37E?
Surfaces are used as-reflowed or fused/hot-air levelled; do not anodize or paint — clean flux residues with saponifier or IPA and avoid abrasive polishing, which embeds grit in the soft metal.
Can Sn63Pb37E be formed, bent or molded?
Eutectic freezing gives excellent castability and fluidity; extrudes into wire and rolls into foil at room temperature but creeps and recrystallises, so stored preforms should be used within their shelf life.
What is the maximum service temperature of Sn63Pb37E?
Sn63Pb37E is rated for continuous use to about 100°C (212 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does Sn63Pb37E cost?
Sn63Pb37E is a high-cost solder & low-melting alloy ($$$$), 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
- ISO 9453 — Soft solder alloys: chemical compositions and forms — ISO (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys and Fluxed/Non-Fluxed Solid Solders — IPC/JEDEC (2013)
- GB/T 3131 (2020)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering (soldering section) — ASM International (1993)
- NIST Database of Solder Properties (Sn-Pb eutectic) — NIST (2002)
- Sn63Pb37 solder bar / cored wire / paste technical data — Alpha Assembly / Indium Corporation (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.