Solder & Low-Melting Alloy Bi57Sn42Ag1 AS-REFLOWED
Heat-treated state
Reference condition for joint mechanical data after reflow at 170–190 °C peak.
Values for the AS-REFLOWED condition
What is Bi57Sn42Ag1 AS-REFLOWED?
Bi57Sn42Ag1 AS-REFLOWED is Bi57Sn42Ag1 heat treated to AS-REFLOWED — reference condition for joint mechanical data after reflow at 170–190 °C peak. Bi57Sn42Ag1 AS-REFLOWED has a yield strength of 40 MPa (5.8 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 88% of solder & low-melting alloy grades. Elongation at break is 35% and the elastic modulus is 42 GPa (6.09 Msi). Bi57Sn42Ag1 AS-REFLOWED has a density of 8.57 g/cm³ (0.31 lb/in³), heavier than 53% of solder & low-melting alloy grades. It melts at 137°C (279 °F).
Advantages
- High strength — 40 MPa (5.8 ksi), better than 88% of solder & low-melting alloy grades
- Good corrosion resistance — 55/100, better than 78% of solder & low-melting alloy grades
Limitations
- Poor heat conductor — 19 W/m·K (11 BTU/hr·ft·°F), worse than 92% of solder & low-melting alloy grades
- Low electrical conductivity — 5 % IACS, worse than 90% of solder & low-melting alloy grades
- Limited service temperature — 80°C (176 °F), worse than 88% of solder & low-melting alloy grades
- Limited formability — 65/100, worse than 75% of solder & low-melting alloy grades
Bi57Sn42Ag1 AS-REFLOWED properties
Typical room-temperature values for Bi57Sn42Ag1 AS-REFLOWED; 7 are specific to this condition. Other listed values are Bi57Sn42Ag1 reference data and may not represent this condition. Bars are the position among solder & low-melting alloy grades.
Physical3
Bi57Sn42Ag1 AS-REFLOWED has a density of 8.57 g/cm³ (0.31 lb/in³), heavier than 53% of solder & low-melting alloy grades. It melts at 137°C (279 °F).
Mechanical11
Bi57Sn42Ag1 AS-REFLOWED has a yield strength of 40 MPa (5.8 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 88% of solder & low-melting alloy grades. Elongation at break is 35% and the elastic modulus is 42 GPa (6.09 Msi).
Thermal6
Bi57Sn42Ag1 AS-REFLOWED is rated for continuous service to 80°C (176 °F). It conducts heat at 19 W/m·K (11 BTU/hr·ft·°F), worse than 92% of solder & low-melting alloy grades. Thermal expansion is 15 µm/m·K (8.33 µin/in·°F).
Electrical3
Bi57Sn42Ag1 AS-REFLOWED conducts electricity at 5 % IACS, worse than 90% 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 Bi57Sn42Ag1 AS-REFLOWED takes about 170 MJ of energy and emits 12 kg of CO₂ — less than 56% of solder & low-melting alloy grades. Typical recycled content is 20%.
Manufacturability7
Bi57Sn42Ag1 AS-REFLOWED's machinability is fair (35/100, better than 58% of solder & low-melting alloy grades); weldability poor (20/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Bi57Sn42Ag1 AS-REFLOWED
Is Bi57Sn42Ag1 easy to machine?
Very soft and gummy — use sharp positive-rake tools, high rake, light cuts and coolant; usually cast/stamped to size rather than machined.
Can Bi57Sn42Ag1 be welded?
Not fusion-welded; it is the filler itself — reflow at 170–190 °C peak, keep pot temperature ≤200 °C to limit dross and Bi segregation.
Can Bi57Sn42Ag1 be formed, bent or molded?
Readily extruded to wire and rolled to foil/preforms; avoid high strain-rate bending of finished joints because Bi-rich phase is notch sensitive.
What surface finishes work on Bi57Sn42Ag1?
Wets Cu, Ni/Au (ENIG) and OSP finishes well with mild no-clean flux; never solder to Pb-containing finishes (96 °C ternary); clean halide residues to avoid dendrite growth.
Bi57Sn42Ag1 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 |
|---|---|---|
| Biprimary constituent, near Bi-Sn eutectic | 56 – 58 | 57 |
| Aggrain refinement, improves ductility/wetting | 0.8 – 1.2 | 1 |
| PbRoHS limit <0.1 wt%; low Pb critical to avoid 96 °C ternary | ≤ 0.07 | |
| Cuimpurity | ≤ 0.05 | |
| Feimpurity | ≤ 0.02 | |
| Znimpurity, degrades wetting | ≤ 0 | |
| CdRoHS-restricted impurity | ≤ 0 | |
| Sbimpurity | ≤ 0.05 | |
| Asimpurity | ≤ 0.03 | |
| Sn | balance |
Bi57Sn42Ag1 AS-REFLOWED — frequently asked
What is Bi57Sn42Ag1 AS-REFLOWED used for?
Bi57Sn42Ag1 AS-REFLOWED is typically used for low-temp SMT reflow, step soldering below higher-melt joints, temperature-sensitive component assembly and LED module soldering. In short: low-temperature RoHS solder; reflows at 170–190 °C; strongest alloy in family.
What is the yield strength of Bi57Sn42Ag1 AS-REFLOWED?
Bi57Sn42Ag1 AS-REFLOWED has a typical yield strength of 40 MPa (5.8 ksi) and a tensile strength of 62 MPa (8.99 ksi) — stronger than 88% of solder & low-melting alloy grades.
Is Bi57Sn42Ag1 AS-REFLOWED easy to machine?
Not especially — machinability is rated fair (35/100, better than 58% of solder & low-melting alloy grades). Very soft and gummy — use sharp positive-rake tools, high rake, light cuts and coolant; usually cast/stamped to size rather than machined.
Can Bi57Sn42Ag1 AS-REFLOWED be welded?
Not readily — weldability is rated poor (20/100). Not fusion-welded; it is the filler itself — reflow at 170–190 °C peak, keep pot temperature ≤200 °C to limit dross and Bi segregation.
What surface finishes work on Bi57Sn42Ag1 AS-REFLOWED?
Wets Cu, Ni/Au (ENIG) and OSP finishes well with mild no-clean flux; never solder to Pb-containing finishes (96 °C ternary); clean halide residues to avoid dendrite growth.
Can Bi57Sn42Ag1 AS-REFLOWED be formed, bent or molded?
Readily extruded to wire and rolled to foil/preforms; avoid high strain-rate bending of finished joints because Bi-rich phase is notch sensitive.
What is the maximum service temperature of Bi57Sn42Ag1 AS-REFLOWED?
Bi57Sn42Ag1 AS-REFLOWED is rated for continuous use to about 80°C (176 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- J-STD-006 Requirements for Electronic Grade Solder Alloys — IPC/JEDEC (2013)
- GB/T 20422 (2018)
- NIST Solder Alloy Property Database (Bi-Sn systems) — NIST (2002)
- ASM Handbook Vol. 3 — Alloy Phase Diagrams (Bi-Sn, Bi-Sn-Ag) — ASM International (2016)
- Low-temperature Bi-Sn-Ag solder paste and preform datasheets — Indium Corporation / AIM Solder / Alpha Assembly (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.