Solder & Low-Melting Alloy Sn63Pb37Sb AS-SOLDERED
Heat-treated state
Reference condition for joint design: strength is dominated by joint geometry, IMC layer and creep at the low homologous temperature.
Values for the AS-SOLDERED condition
What is Sn63Pb37Sb AS-SOLDERED?
Sn63Pb37Sb AS-SOLDERED is Sn63Pb37Sb heat treated to AS-SOLDERED — reference condition for joint design: strength is dominated by joint geometry, IMC layer and creep at the low homologous temperature. Sn63Pb37Sb AS-SOLDERED has a yield strength of 38 MPa (5.51 ksi) and a tensile strength of 55 MPa (7.98 ksi) — stronger than 85% of solder & low-melting alloy grades. Elongation at break is 32% and the elastic modulus is 32 GPa (4.64 Msi). Sn63Pb37Sb AS-SOLDERED 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).
Advantages
- High strength — 38 MPa (5.51 ksi), better than 85% of solder & low-melting alloy grades
Limitations
- Difficult to machine — 20/100, worse than 94% of solder & low-melting alloy grades
Sn63Pb37Sb AS-SOLDERED properties
Typical room-temperature values for Sn63Pb37Sb AS-SOLDERED; 4 are specific to this condition. Other listed values are Sn63Pb37Sb reference data and may not represent this condition. Bars are the position among solder & low-melting alloy grades.
Physical3
Sn63Pb37Sb AS-SOLDERED 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).
Mechanical10
Sn63Pb37Sb AS-SOLDERED has a yield strength of 38 MPa (5.51 ksi) and a tensile strength of 55 MPa (7.98 ksi) — stronger than 85% of solder & low-melting alloy grades. Elongation at break is 32% and the elastic modulus is 32 GPa (4.64 Msi).
Thermal6
Sn63Pb37Sb AS-SOLDERED 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
Sn63Pb37Sb AS-SOLDERED conducts electricity at 11.5 % IACS, better than 71% 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 Sn63Pb37Sb AS-SOLDERED takes about 210 MJ of energy and emits 11 kg of CO₂ — more than 57% of solder & low-melting alloy grades. Typical recycled content is 30%.
Manufacturability7
Sn63Pb37Sb AS-SOLDERED's machinability is poor (20/100, worse than 94% of solder & low-melting alloy grades); weldability poor (20/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Sn63Pb37Sb AS-SOLDERED
Is Sn63Pb37Sb easy to machine?
Extremely soft and gummy — use sharp high-rake tools, flood lubricant and light cuts; solder is normally cast, extruded or stamped rather than machined.
Can Sn63Pb37Sb be welded?
Not fusion-welded; the alloy is itself the filler and is applied by wave, dip, iron, reflow or vapour-phase soldering at 210–250 °C peak.
Can Sn63Pb37Sb be formed, bent or molded?
Casts and extrudes easily at the 183 °C eutectic with a negligible pasty range; wire drawing and preform stamping need no intermediate anneal.
What surface finishes work on Sn63Pb37Sb?
Remove flux residues (IPA/saponifier or leave no-clean per IPC-610); avoid Zn-plated or Cd-bearing mating surfaces with Sb-bearing solder, and note RoHS restrictions on lead.
Sn63Pb37Sb 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 |
|---|---|---|
| Snnear-eutectic tin content | 62.5 – 63.5 | 63 |
| Sbstrengthening / anti-creep addition; some specs allow 0.12–0.50 | 0.2 – 0.5 | 0.35 |
| Biimpurity limit | ≤ 0.1 | |
| Cuimpurity limit | ≤ 0.05 | |
| Agimpurity limit | ≤ 0.05 | |
| Asimpurity limit | ≤ 0.03 | |
| Feimpurity limit | ≤ 0.02 | |
| Znimpurity limit (wetting) | ≤ 0 | |
| Alimpurity limit (wetting) | ≤ 0 | |
| Cdimpurity limit | ≤ 0 | |
| Pb | balance |
Sn63Pb37Sb AS-SOLDERED — frequently asked
What is Sn63Pb37Sb AS-SOLDERED used for?
Sn63Pb37Sb AS-SOLDERED is typically used for mechanically stressed electrical joints, automotive wiring harness soldering and terminal connections. In short: creep-resistant leaded eutectic; strongest Sn63Pb37 variant; 183 °C eutectic melt.
What is the yield strength of Sn63Pb37Sb AS-SOLDERED?
Sn63Pb37Sb AS-SOLDERED has a typical yield strength of 38 MPa (5.51 ksi) and a tensile strength of 55 MPa (7.98 ksi) — stronger than 85% of solder & low-melting alloy grades.
Is Sn63Pb37Sb AS-SOLDERED easy to machine?
Not especially — machinability is rated poor (20/100, worse than 94% of solder & low-melting alloy grades). Extremely soft and gummy — use sharp high-rake tools, flood lubricant and light cuts; solder is normally cast, extruded or stamped rather than machined.
Can Sn63Pb37Sb AS-SOLDERED be welded?
Not readily — weldability is rated poor (20/100). Not fusion-welded; the alloy is itself the filler and is applied by wave, dip, iron, reflow or vapour-phase soldering at 210–250 °C peak.
What surface finishes work on Sn63Pb37Sb AS-SOLDERED?
Remove flux residues (IPA/saponifier or leave no-clean per IPC-610); avoid Zn-plated or Cd-bearing mating surfaces with Sb-bearing solder, and note RoHS restrictions on lead.
Can Sn63Pb37Sb AS-SOLDERED be formed, bent or molded?
Casts and extrudes easily at the 183 °C eutectic with a negligible pasty range; wire drawing and preform stamping need no intermediate anneal.
What is the maximum service temperature of Sn63Pb37Sb AS-SOLDERED?
Sn63Pb37Sb AS-SOLDERED 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.
Sources
- ISO 9453 — Soft solder alloys: chemical compositions and forms — ISO (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys — IPC (2013)
- GB/T 3131 (2020)
- ASM Handbook Vol.3 — Alloy Phase Diagrams / Soldering data — ASM International (1992)
- NIST Database for Solder Properties with Emphasis on New Lead-free Solders — NIST/Colorado School of Mines (2002)
- Sn63Pb37Sb solder bar / cored wire technical data — solder producers (AIM, Indium Corp., ) (2024)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.