Solder & Low-Melting Alloy SAC405
ISO 714 · also IEC A40C5
SAC405 (IEC A40C5) is a higher-silver tin-silver-copper solder that provides improved thermal fatigue resistance compared with SAC305, favoured for high-reliability and high-vibration electronic assemblies.
Reference datasheet — SAC405 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 SAC405?
SAC405 (IEC A40C5) is a higher-silver tin-silver-copper solder that provides improved thermal fatigue resistance compared with SAC305, favoured for high-reliability and high-vibration electronic assemblies. It is supplied as bar, solid and cored wire, paste, spheres, preforms and reflowed joints, with a 240–250 °C reflow peak — 30–40 °C hotter than Sn-Pb profiles. Bulk properties are 40 MPa yield, 52 MPa tensile, 28% elongation and 16 HB, with service to about 125 °C. The silver content makes it the most expensive of the common SAC grades; SAC305 is the lower-cost alternative. SAC405 has a density of 7.44 g/cm³ (0.269 lb/in³), lighter than 63% of solder & low-melting alloy grades. It melts at 217°C (423 °F). SAC405 has a yield strength of 40 MPa (5.8 ksi) and a tensile strength of 52 MPa (7.54 ksi) — stronger than 88% of solder & low-melting alloy grades. Elongation at break is 28% and the elastic modulus is 51 GPa (7.4 Msi).
What is SAC405 used for?
- Automotive electronics
- Military/aerospace assembly
- BGA reflow soldering
Advantages
- Conducts heat well — 62 W/m·K (35.8 BTU/hr·ft·°F), better than 93% of solder & low-melting alloy grades
- Stiff — 51 GPa (7.4 Msi), better than 91% of solder & low-melting alloy grades
- High strength — 40 MPa (5.8 ksi), better than 88% of solder & low-melting alloy grades
- High electrical conductivity — 13 % IACS, better than 87% of solder & low-melting alloy grades
- High service temperature — 125°C (257 °F), better than 80% of solder & low-melting alloy grades
Limitations
- High embodied carbon — 21 kg CO₂/kg, worse than 89% of solder & low-melting alloy grades
SAC405 properties
Typical room-temperature values; bars are the position among solder & low-melting alloy grades.
Physical3
SAC405 has a density of 7.44 g/cm³ (0.269 lb/in³), lighter than 63% of solder & low-melting alloy grades. It melts at 217°C (423 °F).
Mechanical11
SAC405 has a yield strength of 40 MPa (5.8 ksi) and a tensile strength of 52 MPa (7.54 ksi) — stronger than 88% of solder & low-melting alloy grades. Elongation at break is 28% and the elastic modulus is 51 GPa (7.4 Msi).
Thermal6
SAC405 is rated for continuous service to 125°C (257 °F). It conducts heat at 62 W/m·K (35.8 BTU/hr·ft·°F), better than 93% of solder & low-melting alloy grades. Thermal expansion is 21.5 µm/m·K (11.9 µin/in·°F).
Electrical3
SAC405 conducts electricity at 13 % IACS, better than 87% of solder & low-melting alloy grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), better than 78% of solder & low-melting alloy grades.
Sustainability4
Producing a kilogram of SAC405 takes about 350 MJ of energy and emits 21 kg of CO₂ — more than 92% of solder & low-melting alloy grades. Typical recycled content is 30%.
Manufacturability7
SAC405's machinability is poor (30/100, worse than 60% of solder & low-melting alloy grades); weldability poor (20/100); formability excellent (85/100).
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. SAC405 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with SAC405
Is SAC405 easy to machine?
Rarely machined; extremely soft and gummy — use sharp high-rake tools, high speed, low feed, and avoid heat build-up above ~150 °C.
Can SAC405 be welded?
Not welded structurally; the alloy is applied by wave, reflow (peak 240–250 °C), selective, laser or iron soldering with a 30–40 °C hotter profile than Sn-Pb.
Can SAC405 be formed, bent or molded?
Extruded into wire, rolled to ribbon/preforms and atomized into Type 3–5 powder or spheres; keep atomization inert to limit oxide skin.
SAC405 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 |
|---|---|---|
| Agforms Ag3Sn strengthening phase | 3.8 – 4.2 | 4 |
| Cusuppresses Cu pad dissolution; forms Cu6Sn5 | 0.4 – 0.6 | 0.5 |
| Pbimpurity limit; RoHS lead-free | ≤ 0.1 | |
| Sbimpurity limit | ≤ 0.2 | |
| Biimpurity limit | ≤ 0.1 | |
| Feimpurity limit | ≤ 0.02 | |
| Znimpurity limit; degrades wetting | ≤ 0 | |
| Alimpurity limit; causes dross/grittiness | ≤ 0 | |
| Asimpurity limit | ≤ 0.03 | |
| Cdimpurity limit | ≤ 0 | |
| Niimpurity limit unless intentionally doped | ≤ 0.01 | |
| Snbalance, ~95.5 % | balance |
What surface finishes work on SAC405?
No plating or anodizing; finish is controlled by flux choice — remove water-soluble or activated rosin residues by DI wash to prevent dendritic growth and creep corrosion.
Equivalent designations
Standards and trade names that resolve to Solder & Low-Melting Alloy SAC405 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ISO
- 714
- Trade names
- IEC A40C5
How much does SAC405 cost?
SAC405 is a high-cost solder & low-melting alloy ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
SAC405 — frequently asked
What is SAC405 used for?
SAC405 is typically used for automotive electronics, military/aerospace assembly and BGA reflow soldering. In short: highest-silver common SAC; best thermal fatigue life; high-reliability lead-free solder.
What is the yield strength of SAC405?
SAC405 has a typical yield strength of 40 MPa (5.8 ksi) and a tensile strength of 52 MPa (7.54 ksi) — stronger than 88% of solder & low-melting alloy grades.
Is SAC405 easy to machine?
Not especially — machinability is rated poor (30/100, worse than 60% of solder & low-melting alloy grades). Rarely machined; extremely soft and gummy — use sharp high-rake tools, high speed, low feed, and avoid heat build-up above ~150 °C.
Can SAC405 be welded?
Not readily — weldability is rated poor (20/100). Not welded structurally; the alloy is applied by wave, reflow (peak 240–250 °C), selective, laser or iron soldering with a 30–40 °C hotter profile than Sn-Pb.
What surface finishes work on SAC405?
No plating or anodizing; finish is controlled by flux choice — remove water-soluble or activated rosin residues by DI wash to prevent dendritic growth and creep corrosion.
Can SAC405 be formed, bent or molded?
Extruded into wire, rolled to ribbon/preforms and atomized into Type 3–5 powder or spheres; keep atomization inert to limit oxide skin.
What is the maximum service temperature of SAC405?
SAC405 is rated for continuous use to about 125°C (257 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does SAC405 cost?
SAC405 is a high-cost solder & low-melting alloy ($$$$), 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
- J-STD-006C Requirements for Electronic Grade Solder Alloys — IPC/JEDEC (2013)
- IEC 61190-1-3 Requirements for electronic grade solder alloys — IEC (2007)
- Properties of Lead-Free Solders (solder property database) — NIST (2002)
- SAC405 alloy and solder paste technical data — Indium Corporation (2023)
- Lead-free alloy selection guide (SAC305/SAC405) — Alpha Assembly Solutions / Kester (2022)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering — ASM International (1993)
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.