Solder & Low-Melting Alloy Pb60Sn40-SN40A
Grade
ASTM B32 Sn40 · GB HLSnPb40-60 · ISO 9453-114
SN40A = low-antimony composition
Choose when soldering zinc- or galvanised-coated parts, or where antimony is restricted; the standard general-purpose 40/60.
Values for the SN40A condition
Other Pb60Sn40 tempers and conditions
Pb60Sn40 is listed in 2 conditions; see the grade overview at Pb60Sn40.
- SN40A
- SN40B
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SN40AThis page Low-antimony composition | Choose when soldering zinc- or galvanised-coated parts, or where antimony is restricted; the standard general-purpose 40/60. | 24 | 38 | 45 | 12 HB | 10.1 % IACS |
Antimonial | Pick for slightly higher strength and creep resistance in radiators and heavy sheet-metal work; do not use on zinc or galvanised surfaces. | 30 | 45 | 30 | 14 HB | 9.6 % IACS |
What is Pb60Sn40-SN40A?
Pb60Sn40-SN40A is Pb60Sn40 in the SN40A grade — choose when soldering zinc- or galvanised-coated parts, or where antimony is restricted; the standard general-purpose 40/60. Pb60Sn40-SN40A has a yield strength of 24 MPa (3.48 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 66% of solder & low-melting alloy grades. Elongation at break is 45% and the elastic modulus is 24 GPa (3.48 Msi). Pb60Sn40-SN40A has a density of 9.29 g/cm³ (0.336 lb/in³), heavier than 62% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Advantages
- Ductile — tolerates forming and impact — 45%, better than 84% of solder & low-melting alloy grades
Pb60Sn40-SN40A properties
Typical room-temperature values for Pb60Sn40-SN40A; 16 are specific to this condition. Other listed values are Pb60Sn40 reference data and may not represent this condition. Bars are the position among solder & low-melting alloy grades.
Physical3
Pb60Sn40-SN40A has a density of 9.29 g/cm³ (0.336 lb/in³), heavier than 62% of solder & low-melting alloy grades. It melts at 183°C (361 °F).
Mechanical10
Pb60Sn40-SN40A has a yield strength of 24 MPa (3.48 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 66% of solder & low-melting alloy grades. Elongation at break is 45% and the elastic modulus is 24 GPa (3.48 Msi).
Thermal6
Pb60Sn40-SN40A 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 24.5 µm/m·K (13.6 µin/in·°F).
Electrical3
Pb60Sn40-SN40A conducts electricity at 10.1 % IACS, better than 57% 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 Pb60Sn40-SN40A takes about 145 MJ of energy and emits 7.6 kg of CO₂ — less than 59% of solder & low-melting alloy grades. Typical recycled content is 55%.
Manufacturability7
Pb60Sn40-SN40A's machinability is poor (30/100, worse than 60% 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 Pb60Sn40-SN40A
Is Pb60Sn40 easy to machine?
Rarely machined — extremely soft and gummy; use sharp high-rake tools, high speed, low feed and paraffin lubricant, and avoid lead dust exposure.
Can Pb60Sn40 be welded?
Not fusion-welded; joints are made by remelting the solder itself with a torch, iron or solder pot at 260–330 °C using zinc-chloride or rosin flux.
Can Pb60Sn40 be formed, bent or molded?
Casts, extrudes and rolls easily at room temperature; the wide 55 °C pasty range lets it be wiped and shaped on plumbing joints but requires the work to be held still until fully frozen.
What surface finishes work on Pb60Sn40?
Solder surfaces tarnish grey; brush-clean and remove corrosive flux residues with hot water or solvent — do not use on potable water lines or food-contact parts (lead).
Pb60Sn40 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 grade Sn40 | 39.5 – 40.5 | 40 |
| SbSn40A; Sn40B is 1.8–2.4 % Sb | 0 – 0.12 | 0.05 |
| Bi | ≤ 0.25 | — |
| Cu | ≤ 0.08 | — |
| Ag | ≤ 0.02 | — |
| Fe | ≤ 0.02 | — |
| As | ≤ 0.03 | — |
| Zn | ≤ 0.01 | — |
| Al | ≤ 0.01 | — |
| Pbbalance, nominally 60 % | balance | — |
Pb60Sn40-SN40A — frequently asked
What is Pb60Sn40-SN40A used for?
Pb60Sn40-SN40A is typically used for plumbing joints, sheet metal seaming, automotive body solder and radiator repair. In short: low-tin, low-cost solder; wide 55 °C pasty range; body-solder and seam filler.
What is the yield strength of Pb60Sn40-SN40A?
Pb60Sn40-SN40A has a typical yield strength of 24 MPa (3.48 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 66% of solder & low-melting alloy grades. Strength varies by condition: see the 2 listed tempers.
Is Pb60Sn40-SN40A easy to machine?
Not especially — machinability is rated poor (30/100, worse than 60% of solder & low-melting alloy grades). Rarely machined — extremely soft and gummy; use sharp high-rake tools, high speed, low feed and paraffin lubricant, and avoid lead dust exposure.
Can Pb60Sn40-SN40A be welded?
Not readily — weldability is rated poor (20/100). Not fusion-welded; joints are made by remelting the solder itself with a torch, iron or solder pot at 260–330 °C using zinc-chloride or rosin flux.
What surface finishes work on Pb60Sn40-SN40A?
Solder surfaces tarnish grey; brush-clean and remove corrosive flux residues with hot water or solvent — do not use on potable water lines or food-contact parts (lead).
Can Pb60Sn40-SN40A be formed, bent or molded?
Casts, extrudes and rolls easily at room temperature; the wide 55 °C pasty range lets it be wiped and shaped on plumbing joints but requires the work to be held still until fully frozen.
What is the maximum service temperature of Pb60Sn40-SN40A?
Pb60Sn40-SN40A 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
- ASTM B32 — Standard Specification for Solder Metal — ASTM International (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys — IPC (2013)
- GB/T 3131 — SAC/ (2020)
- ASM Handbook Vol.6 — Welding, Brazing and Soldering (Solder alloy properties) — ASM International (1993)
- NIST Database of Solder Properties — NIST (2002)
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.