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Tin-Lead Solders and Lead Alloys

Tin-lead solders run from the 63/37 eutectic, which melts sharply at 183 °C and wets copper better than any lead-free alloy, through pasty 60/40 and 50/50 grades for hand and sheet-metal work, to the lead-rich alloys that melt at 300 °C and above for step soldering and die attach. The same group holds the engineering lead alloys — antimonial, chemical, tellurium and calcium-tin lead — used for battery grids, chemical linings, shielding and sheet. The bulk alloys yield at 30–50 MPa and creep at room temperature; lead makes the joint ductile and forgiving, which is why exempt high-reliability industries still specify it.

Popular tin-lead solder grades

Compare in the explorer
GradeYield, MPaTensile, MPaDensity, g/cm³MachinabilityWeldabilityBest for
Sn63Pb3727468.4Poor—Eutectic electronics standard, 183 °C
Sn60Pb4032558.52Poor—General-purpose wire and bar; hand work
Sn62Pb36Ag234508.42Poor—Silver-plated terminations and hybrids
Sn40Pb6022389.29Fair—Wiping, radiators and body solder
Pb90Sn10152610.75PoorPoorStep soldering and lamp bases, 275–302 °C
Pb95Sn5132411.03PoorPoorDie attach and first-level joints, 308–312 °C
Antimonial Lead 6%255010.88Very goodGoodCast battery grids and hard lead parts

All 48 tin-lead solder grades

Choose tin-lead solder for

Aerospace, defence, medical and other RoHS-exempt electronics, rework and repair of existing tin-lead assemblies, hybrid and ceramic modules, radiators and tinned sheet metal, and step-soldered packages where a 300 °C first-level joint must survive a 220 °C second reflow; the lead alloys for lead-acid battery grids, chemical-plant linings, radiation shielding and roofing sheet.

Look elsewhere when

The product ships into RoHS markets or touches drinking water and food (SAC305, Sn99.3Cu0.7, Sn96.5Ag3.5), a component cannot take even 183 °C (Sn42Bi58 at 138 °C), the joint must hold above 150 °C in service (a silver braze — high-lead solders soften long before they melt), or the part needs strength (no solder is structural; use a mechanical joint and let the solder seal and conduct).

Tensile strength against elongation at break, Tin-lead solders & lead alloys among every solder & low-melting alloy grade

No materials in view have both of these properties.

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Tin-lead solder by application

Exempt electronics assembly
Sn63Pb37 paste, wire and bar; Sn63Pb37E where the specification calls for the low-impurity electronic grade. Sn62Pb36Ag2 on silver-bearing terminations.
Step soldering and die attach
Pb95Sn5, Pb93Sn5Ag2 or Pb90Sn10 for the first joint at about 300 °C, then Sn63Pb37 or SAC305 for the board-level joint 90 °C lower without remelting the first.
Radiators and sheet metal
Sn40Pb60 and Sn30Pb70 for wiping and filling — the wide pasty range lets the joint be shaped; Sn50Pb50 for tinned steel and copper fabrication.
Battery grids and chemical linings
Antimonial Lead 6% and Pb-Ca-Sn Battery Grid Alloy for cast and expanded grids, Chemical Lead for sulphuric-acid vessels and linings, Tellurium Lead where the sheet must work-harden and resist creep.

Working with tin-lead solder

Process
Reflow Sn63Pb37 with a 205–220 °C peak and 30–60 s above 183 °C; wave pots run 245–255 °C; hand soldering uses a 315–370 °C tip with a rosin flux (RMA or ROL0). It wets copper, tin, nickel and gold readily and tolerates mild oxidation, which is why it forgives poor process control better than SAC. High-lead alloys need 350–400 °C and a more active flux.
Joint reliability
The eutectic joint is ductile, so it survives drops and mismatched expansion better than SAC, but it fatigues faster in thermal cycling above 100 °C and creeps under sustained load at room temperature. Gold dissolves into tin-lead and above about 3 % embrittles the joint — strip thick gold or use Sn62Pb36Ag2 on silver. Tin whiskers are not a concern once the lead content exceeds about 3 %.
RoHS and regulatory
Lead above 0.1 % in a homogeneous material is prohibited by RoHS, so tin-lead needs an exemption (aerospace, defence, some medical and monitoring equipment) or a market outside its scope. Alloys with 85 % or more lead are exempt for high-melt applications under exemption 7(a). Specify to J-STD-006 or ASTM B32 and keep tin-lead and lead-free processes physically separate.
Storage and handling
Wire and bar keep indefinitely; paste is refrigerated at 0–10 °C with a 6-month life. Lead dust and fume are the hazard, not skin contact — extract fumes at the iron and the pot, skim dross into a closed bin, and keep food away from the bench. Chemical and antimonial lead are cast and rolled at 330–400 °C and are soft enough to cut with hand tools.

Other solder & low-melting alloy series

Tin-Lead Solders and Lead Alloys — frequently asked

What is tin-lead solder?

Tin-lead solders run from the 63/37 eutectic, which melts sharply at 183 °C and wets copper better than any lead-free alloy, through pasty 60/40 and 50/50 grades for hand and sheet-metal work, to the lead-rich alloys that melt at 300 °C and above for step soldering and die attach. The same group holds the engineering lead alloys — antimonial, chemical, tellurium and calcium-tin lead — used for battery grids, chemical linings, shielding and sheet. The bulk alloys yield at 30–50 MPa and creep at room temperature; lead makes the joint ductile and forgiving, which is why exempt high-reliability industries still specify it.

Which grade of tin-lead solder should I use?

Sn63Pb37 wherever the exemption allows: it melts at a single temperature, gives the brightest fillet and has fifty years of reliability data. Sn60Pb40 is the general-purpose wire and bar — a 183–190 °C pasty range, slightly cheaper, fine for hand work and sheet metal. Sn62Pb36Ag2 has 2 % silver to stop silver-plated terminations dissolving, so it is the choice on ceramic capacitors and thick-film hybrids. Sn40Pb60 and Sn30Pb70 have wide pasty ranges for wiping, radiator and automotive body work. Pb90Sn10, Pb95Sn5 and Pb93Sn5Ag2 melt above 275 °C and are the first-level solders for die attach and step-soldered assemblies. For the lead alloys, Antimonial Lead 6% for cast grids and hardness, Chemical Lead for acid-process linings, Tellurium Lead for work-hardening sheet and cable sheath, and Pb-Ca-Sn Battery Grid Alloy for maintenance-free batteries.

Which grade of tin-lead solder is the strongest?

Sn63Pb37Sb has the highest yield strength in the series at 38 MPa; Pb-Ca-Sn Battery Grid Alloy follows at 35 MPa. Values are for each grade's default condition.

Which grade of tin-lead solder is easiest to machine?

Antimonial Lead 6% (machinability very good, 80/100), then Antimonial Lead 6% Sb (78/100).

Sn63Pb37 or Sn60Pb40?

For electronics, Sn63Pb37: it freezes at one temperature (183 °C) so a joint disturbed while cooling does not go grainy, and it is what J-STD-001 assumes. Sn60Pb40 freezes over 183–190 °C, costs slightly less and is fine for wiring, sheet metal and plumbing-style work where the joint is not moved during cooling. Strength and wetting are practically the same.

Can I use Sn63Pb37 on a lead-free board?

Only for repair, and only if the exemption covers the product. Tin-lead on SAC-finished pads works if the joint is fully reflowed to a uniform alloy, but a partially mixed joint forms a 179 °C lead-rich phase that fails early. Mixing the other way — a lead-free rework on a tin-lead assembly — is worse, because the higher peak temperature stresses the old joints. Keep one alloy per assembly and document it.