Aluminum BAlSi-5
ASTM AWS A5.8 BAlSi-5 · EN B Al 4045
BAlSi-5 is an aluminum-silicon brazing filler with about 10% Si, covered by AWS A5.8 and equivalent to B Al 4045.
Reference datasheet — BAlSi-5 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.
Values for the O condition
BAlSi-5 tempers and conditions
BAlSi-5 is supplied in 6 conditions, soft to hard. O is the default FabDigit quotes; the values on this page are for it.
Compare all 6 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ODefault 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 |
Supply forms, finishes and certifications
Ways BAlSi-5 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
POWDER | Powder / paste filler | Printing process |
What is BAlSi-5?
BAlSi-5 is an aluminum-silicon brazing filler with about 10% Si, covered by AWS A5.8 and equivalent to B Al 4045. It is most often supplied as the clad layer on 3000-series-core brazing sheet, plus foil, wire and powder, and is the standard filler for automotive and HVAC heat exchanger production brazed at 588-604 °C. Typical as-supplied values are 110 MPa tensile, 50 MPa yield, 20% elongation, 35 HB, 165 W/m·K thermal conductivity and 42% IACS, with a machinability score of 28 and formability score of 65. It is not a structural base metal, anodizes unevenly, and BAlSi-4 (4047) is the choice when higher fluidity and a shorter melting range are needed. BAlSi-5 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). BAlSi-5 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).
What is BAlSi-5 used for?
- clad brazing sheet
- automotive heat exchangers
- condenser/evaporator fabrication
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 properties
Typical room-temperature values for BAlSi-5-O; bars are the position among aluminum grades.
Physical3
BAlSi-5 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 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 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 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 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'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. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the aluminum family
Yield strength against density for every aluminum grade FabDigit runs. BAlSi-5 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with BAlSi-5
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.
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 |
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.
Surface treatments FabDigit runs on aluminum parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Equivalent designations
Standards and trade names that resolve to Aluminum BAlSi-5 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- AWS A5.8 BAlSi-5
- EN / DIN / Werkstoff-Nr.
- B Al 4045
- Other
- 4045
How much does BAlSi-5 cost?
BAlSi-5 is a premium-cost aluminum ($$$), cheaper than about 51% 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.
BAlSi-5 — frequently asked
What is BAlSi-5 used for?
BAlSi-5 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?
BAlSi-5 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 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 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?
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 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?
BAlSi-5 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.
How much does BAlSi-5 cost?
BAlSi-5 is a premium-cost aluminum ($$$), cheaper than about 51% 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
- 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; 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.