Aluminum 4045
AA 4045 · UNS A94045 · EN AW-4045, AW 4045
4045 is a non-heat-treatable Al-Si alloy with about 10 % Si (EN AW-4045, AlSi10), used as the clad layer on aluminum brazing sheet and as BAlSi-5 braze filler.
4045 tempers and conditions
4045 is supplied in 10 conditions, soft to hard.
Compare all 10 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Default stock condition for brazing sheet cladding and formed heat-exchanger parts requiring maximum ductility before the braze cycle. | 45 | 110 | 20 | 30 HB | 41 % IACS |
As fabricated | Use for braze rod, wire and cast/hot-worked stock where no mechanical property limits are guaranteed. | 55 | 115 | 12 | 33 HB | 40 % IACS |
after furnace/CAB braze cycle (fillet metal) | Condition of the solidified 4045 fillet/clad after a 590–605 °C braze cycle; coarse Si structure, essentially annealed. | 60 | 130 | 6 | 40 HB | 38 % IACS |
Strain hardened and partially annealed, quarter hard | Stabilized quarter-hard strip with better ductility than H12 at similar strength. | 100 | 130 | 12 | 36 HB | 40 % IACS |
Strain hardened, quarter hard | Light cold work for slightly stiffer clad sheet that still forms readily. | 110 | 135 | 9 | 38 HB | 40 % IACS |
Strain hardened and partially annealed, half hard | Preferred half-hard temper for brazing sheet that must be roll-formed or stamped before the furnace cycle. | 125 | 155 | 8 | 43 HB | 40 % IACS |
Strain hardened, half hard | Most common as-rolled hard condition for fin and tube brazing sheet needing coil handling stiffness. | 145 | 165 | 5 | 45 HB | 40 % IACS |
Strain hardened and partially annealed, three-quarter hard | Stabilized three-quarter hard strip balancing strength and residual formability. | 155 | 180 | 5 | 50 HB | 40 % IACS |
Strain hardened, three-quarter hard | Higher strength coil for stiff, lightly formed fin stock. | 170 | 190 | 3 | 52 HB | 40 % IACS |
Strain hardened, full hard | Maximum cold-rolled strength; used where flat, springy strip is slit and only bent to large radii. | 195 | 215 | 2 | 58 HB | 40 % IACS |
What is 4045?
4045 is a non-heat-treatable Al-Si alloy with about 10 % Si (EN AW-4045, AlSi10), used as the clad layer on aluminum brazing sheet and as BAlSi-5 braze filler. It is chosen for its low melting range — 577 °C solidus, about 591 °C liquidus — good flow and gap filling in 580–610 °C furnace and CAB brazing, and sound roll bonding to 3003/3005 core alloys; typical forms are clad coil and strip, filler wire and rod. Strength is low, primary silicon is abrasive to tooling, and anodic films come out dark grey, so it is not a structural or decorative alloy. 4047 and 4343 are the nearest brazing alternatives. 4045 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). 4045 has a yield strength of 45 MPa (6.53 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 4045 used for?
- Brazing sheet clad layer over 3003/3005 core
- Automotive radiator and condenser assemblies
- Evaporator plates and tube stock
- Heat exchanger fin stock
- Oil cooler plates
- BAlSi-5 braze filler wire and rod
- Torch and furnace brazed tube-to-header joints
Advantages
- Ductile — tolerates forming and impact — 20%, better than 89% of aluminum grades
- Forms and bends easily — 70/100, better than 83% of aluminum grades
- Conducts heat well — 165 W/m·K (95.3 BTU/hr·ft·°F), better than 79% of aluminum grades
Limitations
- Low strength — 45 MPa (6.53 ksi), worse than 95% of aluminum grades
- Hard to polish — 40/100, worse than 91% of aluminum grades
- Difficult to machine — 38/100, worse than 84% of aluminum grades
4045 properties
Typical room-temperature values; bars are the position among aluminum grades.
Physical3
4045 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).
Mechanical10
4045 has a yield strength of 45 MPa (6.53 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
4045 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 µm/m·K (11.7 µin/in·°F).
Electrical3
4045 conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 58% of aluminum grades.
Sustainability4
Producing a kilogram of 4045 takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability8
4045's machinability is fair (38/100, worse than 84% of aluminum grades); weldability very good (70/100); formability very good (70/100).
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. 4045 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with 4045
Is 4045 easy to machine?
Primary silicon is very abrasive — use PCD or polished-flute carbide, high speed, low feed and flood coolant; expect gummy chips in the O temper.
Can 4045 be welded?
Rarely welded as a base metal; it is itself a filler (BAlSi-5) for GTAW/GMAW/torch brazing of 1000 series, 3000 and 6000 series alloys, and re-melts in furnace/CAB braze cycles at 590–605 °C.
Can 4045 be formed, bent or molded?
Form in O or H24 before brazing; heavy H16/H18 tempers crack on tight bends, and post-braze material is soft and easily distorted.
Manufacturability
The process limits FabDigit applies to 4045. Every 4045 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
Sheet metal
| Formability | Excellent70 / 100 |
|---|---|
| Weldability | Excellent70 / 100 |
4045 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 braze-filler element, lowers melting range | 9 – 11 | 10 |
| Fe | ≤ 0.8 | 0.35 |
| Cu | ≤ 0.3 | 0.05 |
| Mn | ≤ 0.05 | 0.02 |
| Mgkept low for controlled-atmosphere (NOCOLOK) brazing | ≤ 0.05 | 0.01 |
| Zn | ≤ 0.1 | 0.02 |
| Ti | ≤ 0.2 | 0.02 |
| Others (each) | ≤ 0.05 | |
| Others (total) | ≤ 0.15 | |
| Al | balance |
What surface finishes work on 4045?
Chemical/mechanical cleaning and flux removal are the norm; anodizing gives dark grey non-decorative films, so painting or chromate/Zr conversion coating is preferred.
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).
Equivalent designations
Standards and trade names that resolve to Aluminum 4045 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- UNS
- A94045
- Aluminum Association
- AA4045
- EN / DIN / Werkstoff-Nr.
- AW-4045AW 4045AlSi10
- Also called
- BAlSi-5
How much does 4045 cost?
4045 is a standard-cost aluminum ($$), cheaper than about 80% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
4045 — frequently asked
What is 4045 used for?
4045 is typically used for brazing sheet clad layer over 3003/3005 core, automotive radiator and condenser assemblies, evaporator plates and tube stock, heat exchanger fin stock, oil cooler plates and BAlSi-5 braze filler wire and rod. In short: brazing sheet skin alloy; 10% Si.
What is the yield strength of 4045?
4045 has a typical yield strength of 45 MPa (6.53 ksi) and a tensile strength of 110 MPa (16 ksi) — weaker than 95% of aluminum grades. Strength varies by condition: see the 10 listed tempers.
Is 4045 easy to machine?
Not especially — machinability is rated fair (38/100, worse than 84% of aluminum grades). Primary silicon is very abrasive — use PCD or polished-flute carbide, high speed, low feed and flood coolant; expect gummy chips in the O temper.
Can 4045 be welded?
Yes — weldability is rated very good (70/100). Rarely welded as a base metal; it is itself a filler (BAlSi-5) for GTAW/GMAW/torch brazing of 1000 series, 3000 and 6000 series alloys, and re-melts in furnace/CAB braze cycles at 590–605 °C.
What surface finishes work on 4045?
Chemical/mechanical cleaning and flux removal are the norm; anodizing gives dark grey non-decorative films, so painting or chromate/Zr conversion coating is preferred.
Can 4045 be formed, bent or molded?
Form in O or H24 before brazing; heavy H16/H18 tempers crack on tight bends, and post-braze material is soft and easily distorted.
What is the maximum service temperature of 4045?
4045 is rated for continuous use to about 150°C (302 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does 4045 cost?
4045 is a standard-cost aluminum ($$), cheaper than about 80% 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.
Can FabDigit make parts in 4045?
Yes — 4045 is available for sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASTM B209 / B209M — Aluminum and Aluminum-Alloy Sheet and Plate — ASTM International (2021)
- AWS A5.10/A5.10M — Filler Metals for Aluminum and Aluminum Alloys (BAlSi-5) — American Welding Society (2021)
- EN 573-3 / EN 485-2 — Wrought aluminium: composition and mechanical properties of sheet — CEN (2019)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- Aluminium brazing sheet (4045 clad on 3003 core) product data — Aluminium brazing-sheet producers (2023)
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.