Aluminum BAlSi-4-O (Annealed)
Temper
ASTM AWS A5.8 BAlSi-4 · EN B Al 4047A
Pick for rolled brazing foil, shim preforms and the clad layer of brazing sheet where maximum ductility for forming is needed.
Values for the O condition
Other BAlSi-4 tempers and conditions
BAlSi-4 is listed in 4 conditions; see the grade overview at BAlSi-4.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Pick for rolled brazing foil, shim preforms and the clad layer of brazing sheet where maximum ductility for forming is needed. | 60 | 125 | 8 | 45 HB | 39 % IACS |
As fabricated | Pick for remelt ingot, cast rings/washers and preforms fed into dip or furnace brazing lines. | 75 | 160 | 3 | 55 HB | 36 % IACS |
AWDefault As-welded deposit | Default condition: properties of the solidified 4047 deposit or braze fillet after GMAW/GTAW or furnace/dip brazing. | 80 | 170 | 4 | 55 HB | 38 % IACS |
Strain hardened, half hard | Pick for 0.8–1.6 mm MIG spool wire and 2–5 mm TIG rod where drawn stiffness is needed for smooth feeding. | 130 | 195 | 3 | 65 HB | 37 % IACS |
What is BAlSi-4-O?
BAlSi-4-O is BAlSi-4 in the O temper — pick for rolled brazing foil, shim preforms and the clad layer of brazing sheet where maximum ductility for forming is needed. BAlSi-4-O has a yield strength of 60 MPa (8.7 ksi) and a tensile strength of 125 MPa (18.1 ksi) — weaker than 93% of aluminum grades. Elongation at break is 8% and the elastic modulus is 72 GPa (10.4 Msi). BAlSi-4-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 577°C (1,071 °F). AW is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Readily welded — 88/100, better than 85% of aluminum grades
- Conducts heat well — 160 W/m·K (92.4 BTU/hr·ft·°F), better than 76% of aluminum grades
Limitations
- Difficult to machine — 28/100, worse than 94% of aluminum grades
- Low strength — 60 MPa (8.7 ksi), worse than 93% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Low fracture toughness — 17 MPa·√m (15.5 ksi·√in), worse than 83% of aluminum grades
BAlSi-4-O properties
Typical room-temperature values for BAlSi-4-O; 21 are specific to this condition. Other listed values are BAlSi-4 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
BAlSi-4-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 577°C (1,071 °F).
Mechanical14
BAlSi-4-O has a yield strength of 60 MPa (8.7 ksi) and a tensile strength of 125 MPa (18.1 ksi) — weaker than 93% of aluminum grades. Elongation at break is 8% and the elastic modulus is 72 GPa (10.4 Msi).
Thermal6
BAlSi-4-O is rated for continuous service to 150°C (302 °F). It conducts heat at 160 W/m·K (92.4 BTU/hr·ft·°F), better than 76% of aluminum grades. Thermal expansion is 20.4 µm/m·K (11.3 µin/in·°F).
Electrical3
BAlSi-4-O conducts electricity at 39 % IACS, better than 65% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (57/100), better than 52% of aluminum grades.
Sustainability4
Producing a kilogram of BAlSi-4-O takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 76% of aluminum grades. Typical recycled content is 20%.
Manufacturability8
BAlSi-4-O's machinability is poor (28/100, worse than 94% of aluminum grades); weldability excellent (88/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BAlSi-4-O
Is BAlSi-4 easy to machine?
High Si makes the deposit abrasive — use polished-flute carbide or PCD tooling, high speed, generous coolant, and expect rapid edge wear on HSS.
Can BAlSi-4 be welded?
Excellent as a GMAW/GTAW filler for 3xx.x castings and 6000 series where hot-crack resistance matters; do not use where the joint must be anodized or where 5000-series-level ductility/marine service is required.
Can BAlSi-4 be formed, bent or molded?
The alloy itself is barely formable (brittle eutectic); form as thin annealed foil or as the clad layer on 3003-core brazing sheet, and keep bend radii generous.
What surface finishes work on BAlSi-4?
Anodizes dark grey/black and etches unevenly; for cosmetic parts mask fillets, use chemical conversion coating or paint instead of clear anodize.
BAlSi-4 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 |
|---|---|---|
| Sinear-eutectic; sets the 577–582 °C melting range | 11 – 13 | 12 |
| Fe | ≤ 0.8 | 0.4 |
| Cu | ≤ 0.3 | 0.05 |
| Mn | ≤ 0.15 | 0.05 |
| Mgkept low for flux (CAB) brazing; higher Mg grades are for vacuum brazing | ≤ 0.1 | 0.02 |
| Zn | ≤ 0.2 | 0.05 |
| BeAWS A5.8 limit; many suppliers offer Be-free | ≤ 8×10⁻⁴ | 0 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
BAlSi-4-O — frequently asked
What is BAlSi-4-O used for?
BAlSi-4-O is typically used for vacuum brazing, dip brazing, aluminum cookware and heat exchanger fin joints. In short: highest-fluidity aluminum braze filler; eutectic 12% Si composition; poor anodizing response.
What is the yield strength of BAlSi-4-O?
BAlSi-4-O has a typical yield strength of 60 MPa (8.7 ksi) and a tensile strength of 125 MPa (18.1 ksi) — weaker than 93% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is BAlSi-4-O easy to machine?
Not especially — machinability is rated poor (28/100, worse than 94% of aluminum grades). High Si makes the deposit abrasive — use polished-flute carbide or PCD tooling, high speed, generous coolant, and expect rapid edge wear on HSS.
Can BAlSi-4-O be welded?
Yes — weldability is rated excellent (88/100). Excellent as a GMAW/GTAW filler for 3xx.x castings and 6000 series where hot-crack resistance matters; do not use where the joint must be anodized or where 5000-series-level ductility/marine service is required.
What surface finishes work on BAlSi-4-O?
Anodizes dark grey/black and etches unevenly; for cosmetic parts mask fillets, use chemical conversion coating or paint instead of clear anodize.
Can BAlSi-4-O be formed, bent or molded?
The alloy itself is barely formable (brittle eutectic); form as thin annealed foil or as the clad layer on 3003-core brazing sheet, and keep bend radii generous.
What is the maximum service temperature of BAlSi-4-O?
BAlSi-4-O is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between BAlSi-4-AW and BAlSi-4-H14?
AW is the default condition — default condition: properties of the solidified 4047 deposit or braze fillet after GMAW/GTAW or furnace/dip brazing. H14: pick for 0.8–1.6 mm MIG spool wire and 2–5 mm TIG rod where drawn stiffness is needed for smooth feeding. Yield strength is 80 MPa in AW versus 130 MPa in H14.
Sources
- AWS A5.8/A5.8M — Specification for Filler Metals for Brazing and Braze Welding (BAlSi-4) — American Welding Society (2019)
- AWS A5.10/A5.10M — Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods (ER4047) — American Welding Society (2021)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — 4047/4047A — The Aluminum Association (2018)
- EN ISO 17672 / former EN 1044 AL104 aluminium brazing filler metals — ISO/CEN (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Brazing Handbook, 5th ed. — Aluminum Brazing — American Welding Society (2007)
- ER4047 / BAlSi-4 aluminium filler wire and brazing foil datasheets — various filler-metal producers (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.