Solder & Low-Melting Alloy Sn99.3Cu0.7 AS-REFLOWED
Heat-treated state
also SAC0307-precursor
Use these values for joint-level strength predictions immediately after soldering, before thermal aging.
Values for the AS-REFLOWED condition
Other Sn99.3Cu0.7 tempers and conditions
Sn99.3Cu0.7 is listed in 2 conditions; see the grade overview at Sn99.3Cu0.7.
- Aged
- AS-REFLOWED
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Isothermally aged (e.g. 125-150 °C, 500-1000 h) / creep-softened joint | End-of-life design case: coarsened Cu6Sn5 and thick Cu3Sn IMC give lower strength and higher ductility. | 11 | 22 | 45 | 11 HB | 15 % IACS |
AS-REFLOWEDThis page thin joint, as reflowed/wave-soldered (fine as-cast microstructure) | Use these values for joint-level strength predictions immediately after soldering, before thermal aging. | 23 | 38 | 28 | 16 HB | 14 % IACS |
What is Sn99.3Cu0.7 AS-REFLOWED?
Sn99.3Cu0.7 AS-REFLOWED is Sn99.3Cu0.7 heat treated to AS-REFLOWED — use these values for joint-level strength predictions immediately after soldering, before thermal aging. Sn99.3Cu0.7 AS-REFLOWED has a yield strength of 23 MPa (3.34 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 67% of solder & low-melting alloy grades. Elongation at break is 28% and the elastic modulus is 45 GPa (6.53 Msi). Sn99.3Cu0.7 AS-REFLOWED has a density of 7.31 g/cm³ (0.264 lb/in³), lighter than 90% of solder & low-melting alloy grades. It melts at 227°C (441 °F).
Advantages
- Conducts heat well — 65 W/m·K (37.6 BTU/hr·ft·°F), better than 96% of solder & low-melting alloy grades
- High electrical conductivity — 14 % IACS, better than 94% of solder & low-melting alloy grades
- Lightweight — 7.31 g/cm³ (0.264 lb/in³), better than 90% of solder & low-melting alloy grades
Limitations
- Difficult to machine — 18/100, worse than 98% of solder & low-melting alloy grades
- High embodied carbon — 18 kg CO₂/kg, worse than 76% of solder & low-melting alloy grades
Sn99.3Cu0.7 AS-REFLOWED properties
Typical room-temperature values for Sn99.3Cu0.7 AS-REFLOWED; 18 are specific to this condition. Other listed values are Sn99.3Cu0.7 reference data and may not represent this condition. Bars are the position among solder & low-melting alloy grades.
Physical3
Sn99.3Cu0.7 AS-REFLOWED has a density of 7.31 g/cm³ (0.264 lb/in³), lighter than 90% of solder & low-melting alloy grades. It melts at 227°C (441 °F).
Mechanical11
Sn99.3Cu0.7 AS-REFLOWED has a yield strength of 23 MPa (3.34 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 67% of solder & low-melting alloy grades. Elongation at break is 28% and the elastic modulus is 45 GPa (6.53 Msi).
Thermal6
Sn99.3Cu0.7 AS-REFLOWED is rated for continuous service to 100°C (212 °F). It conducts heat at 65 W/m·K (37.6 BTU/hr·ft·°F), better than 96% of solder & low-melting alloy grades. Thermal expansion is 22 µm/m·K (12.2 µin/in·°F).
Electrical3
Sn99.3Cu0.7 AS-REFLOWED conducts electricity at 14 % IACS, better than 94% 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 Sn99.3Cu0.7 AS-REFLOWED takes about 320 MJ of energy and emits 18 kg of CO₂ — more than 81% of solder & low-melting alloy grades. Typical recycled content is 30%.
Manufacturability6
Sn99.3Cu0.7 AS-REFLOWED's machinability is poor (18/100, worse than 98% of solder & low-melting alloy grades); formability excellent (85/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Sn99.3Cu0.7 AS-REFLOWED
Is Sn99.3Cu0.7 easy to machine?
Rarely machined — extremely soft and gummy; if trimming preforms use sharp high-rake tools, low speed, no coolant carry-over into the flux.
Can Sn99.3Cu0.7 be welded?
Not arc-welded; it is the filler itself — process at 250-270 °C pot / 245-260 °C reflow peak with N2 or active no-clean flux, and expect ~15-25 °C more heat than SnPb37.
Can Sn99.3Cu0.7 be formed, bent or molded?
Extrudes and rolls easily to wire, ribbon and stamped preforms; atomized into Type 3/4 powder for paste; anneals at room temperature so cold work does not persist.
What surface finishes work on Sn99.3Cu0.7?
Used as-soldered; keep flux residues cleaned or fully no-clean, avoid bright-Sn-like whisker conditions, and do not plate or anodize the joint.
Sn99.3Cu0.7 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 |
|---|---|---|
| CuISO 9453 alloy 401 / J-STD-006 Sn99.3Cu0.7 | 0.6 – 0.9 | 0.7 |
| PbRoHS limit 0.1 % max; premium bar often <0.05 % | ≤ 0.07 | — |
| Sb | ≤ 0.05 | — |
| Bi | ≤ 0.1 | — |
| Agresidual only | ≤ 0.1 | — |
| As | ≤ 0.03 | — |
| Fe | ≤ 0.02 | — |
| Niintentional 0.05-0.06 % Ni in micro-alloyed SN100C-type variants | ≤ 0.01 | — |
| Zn | ≤ 0 | — |
| Al | ≤ 0 | — |
| Cd | ≤ 0 | — |
| Sn≈99.3 % nominal | balance | — |
Sn99.3Cu0.7 AS-REFLOWED — frequently asked
What is Sn99.3Cu0.7 AS-REFLOWED used for?
Sn99.3Cu0.7 AS-REFLOWED is typically used for lead-free wave soldering, cost-sensitive consumer electronics and general plumbing/HVAC (lead-free). In short: cheapest lead-free solder; silver-free wave alloy; SAC0307 precursor composition.
What is the yield strength of Sn99.3Cu0.7 AS-REFLOWED?
Sn99.3Cu0.7 AS-REFLOWED has a typical yield strength of 23 MPa (3.34 ksi) and a tensile strength of 38 MPa (5.51 ksi) — weaker than 67% of solder & low-melting alloy grades. Strength varies by condition: see the 2 listed tempers.
Is Sn99.3Cu0.7 AS-REFLOWED easy to machine?
Not especially — machinability is rated poor (18/100, worse than 98% of solder & low-melting alloy grades). Rarely machined — extremely soft and gummy; if trimming preforms use sharp high-rake tools, low speed, no coolant carry-over into the flux.
Can Sn99.3Cu0.7 AS-REFLOWED be welded?
Not arc-welded; it is the filler itself — process at 250-270 °C pot / 245-260 °C reflow peak with N2 or active no-clean flux, and expect ~15-25 °C more heat than SnPb37.
What surface finishes work on Sn99.3Cu0.7 AS-REFLOWED?
Used as-soldered; keep flux residues cleaned or fully no-clean, avoid bright-Sn-like whisker conditions, and do not plate or anodize the joint.
Can Sn99.3Cu0.7 AS-REFLOWED be formed, bent or molded?
Extrudes and rolls easily to wire, ribbon and stamped preforms; atomized into Type 3/4 powder for paste; anneals at room temperature so cold work does not persist.
What is the maximum service temperature of Sn99.3Cu0.7 AS-REFLOWED?
Sn99.3Cu0.7 AS-REFLOWED 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 composition and forms (alloy 401, Sn99.3Cu0.7) — ISO (2020)
- J-STD-006 — Requirements for Electronic Grade Solder Alloys and Fluxed/Non-Fluxed Solid Solders — IPC (2013)
- Properties of Lead-Free Solders / Solder Property Database — NIST (2002)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (soldering section) — ASM International (1993)
- Lead-free alloy data sheets (Sn100 / SnCu0.7, SN100C) — Indium Corporation / AIM Solder / Nihon Superior (2023)
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.