Aluminum BAlSi-5-O (Annealed)
Temper · default condition
ASTM AWS A5.8 BAlSi-5 · EN B Al 4045
Default supply state for 4045 clad brazing sheet and bare filler foil — maximum formability before the brazing cycle.
Values for the O condition
Other BAlSi-5 tempers and conditions
BAlSi-5 is listed in 6 conditions; see the grade overview at BAlSi-5.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefaultThis page Annealed | Default supply state for 4045 clad brazing sheet and bare filler foil — maximum formability before the brazing cycle. | 50 | 110 | 20 | 35 HB | 42 % IACS |
As fabricated | Standard state for BAlSi-5 brazing rod, wire and preform ring stock where mechanical properties are not specified. | 65 | 130 | 12 | 40 HB | 42 % IACS |
solidified joint fillet | Property set for the solidified Al-Si fillet itself; use for joint strength checks rather than filler-stock handling. | 80 | 150 | 8 | 55 HB | 38 % IACS |
Strain hardened and partially annealed, half hard | Common brazing-sheet temper when both strength and bendability are needed for header/tube forming. | 120 | 150 | 8 | 46 HB | 41.5 % IACS |
Strain hardened, half hard | Choose for fin/tube stock and brazing sheet that must resist handling and roll-forming loads before brazing. | 130 | 150 | 5 | 48 HB | 41 % IACS |
Strain hardened, full hard | Full-hard thin foil/strip for fin stock and for slitting into braze shims where stiffness matters more than bending. | 170 | 190 | 2 | 55 HB | 40.5 % IACS |
What is BAlSi-5-O?
BAlSi-5-O is BAlSi-5 in the O temper — default supply state for 4045 clad brazing sheet and bare filler foil — maximum formability before the brazing cycle. BAlSi-5-O has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 110 MPa (16 ksi) — weaker than 95% of aluminum grades. Elongation at break is 20% and the elastic modulus is 71 GPa (10.3 Msi). BAlSi-5-O has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 577°C (1,071 °F).
Advantages
- Ductile — tolerates forming and impact — 20%, better than 89% of aluminum grades
- High electrical conductivity — 42 % IACS, better than 81% of aluminum grades
- Forms and bends easily — 65/100, better than 80% of aluminum grades
- Conducts heat well — 165 W/m·K (95.3 BTU/hr·ft·°F), better than 79% of aluminum grades
Limitations
- Hard to polish — 35/100, worse than 98% of aluminum grades
- Low strength — 50 MPa (7.25 ksi), worse than 95% of aluminum grades
- Difficult to machine — 28/100, worse than 94% of aluminum grades
BAlSi-5-O properties
Typical room-temperature values for BAlSi-5-O; 17 are specific to this condition. Other listed values are BAlSi-5 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
BAlSi-5-O has a density of 2.67 g/cm³ (0.0965 lb/in³), lighter than 78% of aluminum grades. It melts at 577°C (1,071 °F).
Mechanical11
BAlSi-5-O has a yield strength of 50 MPa (7.25 ksi) and a tensile strength of 110 MPa (16 ksi) — weaker than 95% of aluminum grades. Elongation at break is 20% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
BAlSi-5-O is rated for continuous service to 150°C (302 °F). It conducts heat at 165 W/m·K (95.3 BTU/hr·ft·°F), better than 79% of aluminum grades. Thermal expansion is 21.4 µm/m·K (11.9 µin/in·°F).
Electrical3
BAlSi-5-O conducts electricity at 42 % IACS, better than 81% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of BAlSi-5-O takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 30%.
Manufacturability8
BAlSi-5-O's machinability is poor (28/100, worse than 94% of aluminum grades); weldability fair (45/100); formability good (65/100).
Common Calculations5
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BAlSi-5-O
Is BAlSi-5 easy to machine?
Machines gummy and the primary silicon is abrasive — use sharp polished carbide, high rake, high speed and generous lubrication; not intended as a machining stock.
Can BAlSi-5 be welded?
Not a structural base metal; as a filler it is used for brazing (588–604 °C) and occasionally GTAW/GMAW of Al-Si castings — avoid arc welding Mg-bearing alloys with it due to brittle Mg2Si.
Can BAlSi-5 be formed, bent or molded?
Clad brazing sheet forms with the 3000-series core; keep bend radii moderate in H1x tempers and avoid cladding cracking or thinning that starves the fillet.
What surface finishes work on BAlSi-5?
Anodizing gives dark, non-uniform films; chromate/no-chrome conversion coating plus paint or e-coat is the practical route, and post-braze flux residues must be washed off.
BAlSi-5 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 |
|---|---|---|
| Siprimary melting-point depressant | 9 – 11 | 10 |
| Fe | ≤ 0.8 | 0.35 |
| Cu | ≤ 0.3 | 0.05 |
| Mn | ≤ 0.05 | — |
| Mgkept low for CAB flux brazing | ≤ 0.05 | — |
| Zn | ≤ 0.1 | — |
| Ti | ≤ 0.2 | — |
| Others (each)0.15 max total | ≤ 0.05 | — |
| Al | balance | — |
BAlSi-5-O — frequently asked
What is BAlSi-5-O used for?
BAlSi-5-O is typically used for clad brazing sheet, automotive heat exchangers and condenser/evaporator fabrication. In short: standard brazing-sheet clad alloy; brazes at 588-604 °C; more ductile than 4047.
What is the yield strength of BAlSi-5-O?
BAlSi-5-O has a typical yield strength of 50 MPa (7.25 ksi) and a tensile strength of 110 MPa (16 ksi) — weaker than 95% of aluminum grades. Strength varies by condition: see the 6 listed tempers.
Is BAlSi-5-O easy to machine?
Not especially — machinability is rated poor (28/100, worse than 94% of aluminum grades). Machines gummy and the primary silicon is abrasive — use sharp polished carbide, high rake, high speed and generous lubrication; not intended as a machining stock.
Can BAlSi-5-O be welded?
With care — weldability is rated fair (45/100). Not a structural base metal; as a filler it is used for brazing (588–604 °C) and occasionally GTAW/GMAW of Al-Si castings — avoid arc welding Mg-bearing alloys with it due to brittle Mg2Si.
What surface finishes work on BAlSi-5-O?
Anodizing gives dark, non-uniform films; chromate/no-chrome conversion coating plus paint or e-coat is the practical route, and post-braze flux residues must be washed off.
Can BAlSi-5-O be formed, bent or molded?
Clad brazing sheet forms with the 3000-series core; keep bend radii moderate in H1x tempers and avoid cladding cracking or thinning that starves the fillet.
What is the maximum service temperature of BAlSi-5-O?
BAlSi-5-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-5-O and BAlSi-5-H18?
O is the default condition — default supply state for 4045 clad brazing sheet and bare filler foil — maximum formability before the brazing cycle. H18: full-hard thin foil/strip for fin stock and for slitting into braze shims where stiffness matters more than bending. Yield strength is 50 MPa in O versus 170 MPa in H18.
Sources
- AWS A5.8/A5.8M — Specification for Filler Metals for Brazing and Braze Welding — AWS (2019)
- Aluminum Association Teal Sheets — International Alloy Designations and Chemical Composition Limits for Wrought Aluminum — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (aluminium brazing) — ASM International (1993)
- Aluminium brazing sheet (4045 clad on 3003 core) product data — Constellium / Novelis (2022)
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.