Aluminum 4045 · temper
Aluminum 4045-O
Properties of the O condition, compared with the other 4045 tempers.
Default stock condition for brazing sheet cladding and formed heat-exchanger parts requiring maximum ductility before the braze cycle.
What is 4045-O?
4045-O is 4045 in the O temper — default stock condition for brazing sheet cladding and formed heat-exchanger parts requiring maximum ductility before the braze cycle. 4045-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 20% and the elastic modulus is 71 GPa (10.3 Msi). 4045-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
- Forms and bends easily — 78/100, better than 87% of aluminum grades
- Conducts heat well — 165 W/m·K (95.3 BTU/hr·ft·°F), better than 79% of aluminum grades
- High electrical conductivity — 41 % IACS, better than 78% of aluminum grades
Limitations
- Low strength — 45 MPa (6.53 ksi), worse than 95% of aluminum grades
- Hard to polish — 40/100, worse than 90% of aluminum grades
- Difficult to machine — 35/100, worse than 86% of aluminum grades
4045-O properties
Typical room-temperature values for 4045-O — 10 properties are specific to this condition; the rest are grade-level values shared by every 4045 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
4045-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).
Mechanical10
4045-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 20% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
4045-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 µm/m·K (11.7 µin/in·°F).
Electrical3
4045-O conducts electricity at 41 % IACS, better than 78% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (48/100), worse than 58% of aluminum grades.
Sustainability4
Producing a kilogram of 4045-O 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-O's machinability is fair (35/100, worse than 86% of aluminum grades); weldability very good (70/100); formability very good (78/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 4045 tempers and conditions
4045 is also supplied in 9 other conditions. The full side-by-side table is on the 4045 overview.
- H14Most common as-rolled hard condition for fin and tube brazing sheet needing coil handling stiffness.145 MPa yield · 45 HB
- H24Preferred half-hard temper for brazing sheet that must be roll-formed or stamped before the furnace cycle.125 MPa yield · 43 HB
- ODefault stock condition for brazing sheet cladding and formed heat-exchanger parts requiring maximum ductility before the braze cycle.45 MPa yield · 30 HB
Working with 4045-O
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 1xxx, 3xxx and 6xxx 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.
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.
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 | — |
4045-O — frequently asked
What is 4045-O used for?
4045-O 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-O?
4045-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 10 listed tempers.
Is 4045-O easy to machine?
Not especially — machinability is rated fair (35/100, worse than 86% 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-O 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 1xxx, 3xxx and 6xxx alloys, and re-melts in furnace/CAB braze cycles at 590–605 °C.
What surface finishes work on 4045-O?
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-O 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-O?
4045-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.
Can FabDigit make parts in 4045-O?
Yes — 4045-O is available for sheet metal with instant online pricing. 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.