Aluminum ER4045-O (Annealed)
Temper
ASTM AWS A5.10 ER4045 · EN S Al 4045
Choose for soft, fully annealed 4045 clad strip or foil that must be formed or roll-bonded before brazing.
Values for the O condition
Other ER4045 tempers and conditions
ER4045 is listed in 5 conditions; see the grade overview at ER4045.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Choose for soft, fully annealed 4045 clad strip or foil that must be formed or roll-bonded before brazing. | 45 | 110 | 24 | 35 HB | 43 % IACS |
As built (as printed) | Use for the re-solidified Al-Si fillet/clad layer in a finished brazed heat exchanger joint. | 55 | 130 | 8 | 48 HB | 40 % IACS |
AWDefault As-welded deposit | Default condition: properties of the ER4045 deposit as laid down by TIG/MIG on aluminium base metal. | 60 | 165 | 12 | 45 HB | 41 % IACS |
Strain hardened, half hard | Half-hard 4045 strip/foil for brazing shims and preforms needing handling stiffness with some formability. | 125 | 150 | 6 | 50 HB | 42 % IACS |
Strain hardened, full hard | Full-hard thin foil/shim stock for flat brazing preforms that are stamped, not formed. | 170 | 190 | 3 | 60 HB | 41 % IACS |
What is ER4045-O?
ER4045-O is ER4045 in the O temper — choose for soft, fully annealed 4045 clad strip or foil that must be formed or roll-bonded before brazing. ER4045-O 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 24% and the elastic modulus is 71 GPa (10.3 Msi). ER4045-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). AW is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Ductile — tolerates forming and impact — 24%, better than 92% of aluminum grades
- Readily welded — 90/100, better than 90% of aluminum grades
- Conducts heat well — 172 W/m·K (99.4 BTU/hr·ft·°F), better than 84% of aluminum grades
- High electrical conductivity — 43 % IACS, better than 83% of aluminum grades
- Forms and bends easily — 70/100, better than 83% of aluminum grades
Limitations
- Hard to polish — 38/100, worse than 97% of aluminum grades
- Low strength — 45 MPa (6.53 ksi), worse than 95% of aluminum grades
- Difficult to machine — 35/100, worse than 86% of aluminum grades
ER4045-O properties
Typical room-temperature values for ER4045-O; 20 are specific to this condition. Other listed values are ER4045 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
ER4045-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).
Mechanical15
ER4045-O 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 24% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
ER4045-O is rated for continuous service to 150°C (302 °F). It conducts heat at 172 W/m·K (99.4 BTU/hr·ft·°F), better than 84% of aluminum grades. Thermal expansion is 21.3 µm/m·K (11.8 µin/in·°F).
Electrical3
ER4045-O conducts electricity at 43 % IACS, better than 83% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (60/100), better than 62% of aluminum grades.
Sustainability4
Producing a kilogram of ER4045-O takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 25%.
Manufacturability8
ER4045-O's machinability is fair (35/100, worse than 86% of aluminum grades); weldability excellent (90/100); formability very good (70/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with ER4045-O
Is ER4045 easy to machine?
Rarely machined; the ~10% Si makes it abrasive — use PCD or polished carbide, high speed, low feed, generous coolant.
Can ER4045 be welded?
Excellent as a filler for 3000/6000 series and cast Al-Si; use AC-TIG or pulsed MIG, keep heat input low, never for 5000 series with >2.5% Mg (brittle Mg2Si) or for parts to be anodized cosmetically.
Can ER4045 be formed, bent or molded?
Very fluid on melting (near-eutectic), ideal for capillary brazing gaps of 0.05–0.15 mm; as strip it is roll-clad onto 3003/3000-series core rather than formed alone.
What surface finishes work on ER4045?
Anodizes dark and blotchy due to silicon; chemical etching darkens the deposit — prefer paint, chromate/Ti-Zr conversion coat or leave as-brazed.
ER4045 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 |
|---|---|---|
| Siprincipal alloying element, lowers melting range | 9 – 11 | 10 |
| Fe | ≤ 0.8 | 0.4 |
| Cu | ≤ 0.3 | 0.05 |
| Mn | ≤ 0.05 | 0.01 |
| Mgkept low for controlled-atmosphere (NOCOLOK) brazing | ≤ 0.05 | 0.01 |
| Zn | ≤ 0.1 | 0.02 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
ER4045-O — frequently asked
What is ER4045-O used for?
ER4045-O is typically used for brazing sheet cladding, heat exchanger fabrication and TIG welding of thin sheet. In short: lowest-melting Al-Si filler; brazing sheet cladding alloy; made for capillary brazing.
What is the yield strength of ER4045-O?
ER4045-O 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 5 listed tempers.
Is ER4045-O easy to machine?
Not especially — machinability is rated fair (35/100, worse than 86% of aluminum grades). Rarely machined; the ~10% Si makes it abrasive — use PCD or polished carbide, high speed, low feed, generous coolant.
Can ER4045-O be welded?
Yes — weldability is rated excellent (90/100). Excellent as a filler for 3000/6000 series and cast Al-Si; use AC-TIG or pulsed MIG, keep heat input low, never for 5000 series with >2.5% Mg (brittle Mg2Si) or for parts to be anodized cosmetically.
What surface finishes work on ER4045-O?
Anodizes dark and blotchy due to silicon; chemical etching darkens the deposit — prefer paint, chromate/Ti-Zr conversion coat or leave as-brazed.
Can ER4045-O be formed, bent or molded?
Very fluid on melting (near-eutectic), ideal for capillary brazing gaps of 0.05–0.15 mm; as strip it is roll-clad onto 3003/3000-series core rather than formed alone.
What is the maximum service temperature of ER4045-O?
ER4045-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 ER4045-AW and ER4045-H18?
AW is the default condition — default condition: properties of the ER4045 deposit as laid down by TIG/MIG on aluminium base metal. H18: full-hard thin foil/shim stock for flat brazing preforms that are stamped, not formed. Yield strength is 60 MPa in AW versus 170 MPa in H18.
Sources
- AWS A5.10/A5.10M — Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods — AWS (2021)
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 6 — Welding, Brazing and Soldering (Aluminum brazing sheet) — ASM International (1993)
- Aluminium brazing sheet / 4045 clad alloy datasheets — Novelis / Granges (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.