Aluminum 4047 · temper
Aluminum 4047-O
Properties of the O condition, compared with the other 4047 tempers.
Pick when maximum ductility is needed for coiling, stamping of brazing foil, or roll-bonded clad sheet before the braze cycle.
What is 4047-O?
4047-O is 4047 in the O temper — pick when maximum ductility is needed for coiling, stamping of brazing foil, or roll-bonded clad sheet before the braze cycle. 4047-O has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 94% of aluminum grades. Elongation at break is 22% and the elastic modulus is 71 GPa (10.3 Msi). 4047-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 577°C (1,071 °F). F is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Readily welded — 92/100, better than 95% of aluminum grades
- Ductile — tolerates forming and impact — 22%, better than 91% of aluminum grades
- Conducts heat well — 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades
Limitations
- Low strength — 55 MPa (7.98 ksi), worse than 94% 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
4047-O properties
Typical room-temperature values for 4047-O — 9 properties are specific to this condition; the rest are grade-level values shared by every 4047 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
4047-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 577°C (1,071 °F).
Mechanical11
4047-O has a yield strength of 55 MPa (7.98 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 94% of aluminum grades. Elongation at break is 22% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
4047-O is rated for continuous service to 150°C (302 °F). It conducts heat at 160 W/m·K (92.4 BTU/hr·ft·°F), better than 75% of aluminum grades. Thermal expansion is 20 µm/m·K (11.1 µin/in·°F).
Electrical3
4047-O conducts electricity at 40 % IACS, better than 72% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (58/100), better than 57% of aluminum grades.
Sustainability4
Producing a kilogram of 4047-O takes about 200 MJ of energy and emits 12 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 20%.
Manufacturability8
4047-O's machinability is fair (35/100, worse than 86% of aluminum grades); weldability excellent (92/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 4047 tempers and conditions
4047 is also supplied in 2 other conditions. The full side-by-side table is on the 4047 overview.
- FDefaultDefault stocked condition for 4047 welding wire, brazing rod, foil and brazing-sheet cladding — no controlled mechanical properties, chosen for melting behaviour rather than strength.70 MPa yield · 52 HB
- OPick when maximum ductility is needed for coiling, stamping of brazing foil, or roll-bonded clad sheet before the braze cycle.55 MPa yield · 42 HB
Working with 4047-O
Is 4047 easy to machine?
Abrasive high-Si microstructure — use polished-flute carbide or PCD tooling, high speed, low feed and flood coolant; expect short tool life vs 6061.
Can 4047 be welded?
This is the filler alloy itself: excellent fluidity and the lowest hot-cracking tendency of the Al-Si fillers, ideal for GTAW/GMAW of 3xx castings and Si-tolerant wrought alloys, but avoid on Mg-bearing 5xxx base metals (brittle Mg2Si) and where post-weld anodizing colour matters.
Can 4047 be formed, bent or molded?
Very high casting/brazing fluidity with minimal shrinkage; wrought forming is limited — cold bending of wire/foil only, no heat-treat strengthening available.
What surface finishes work on 4047?
Anodizes dark and blotchy; prefer chromate/chemical conversion coating, paint, or leave as-brazed; mechanical polishing pulls out Si particles.
4047 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 |
|---|---|---|
| Sinear-eutectic silicon content | 11 – 13 | 12 |
| Fe0.6 max for EN AW-4047A | ≤ 0.8 | — |
| Cu | ≤ 0.3 | — |
| Mn | ≤ 0.15 | — |
| Mg0.10 max; some vacuum-braze variants restrict further | ≤ 0.1 | — |
| Zn | ≤ 0.2 | — |
| Tispecified for 4047A; not limited in AA 4047 | ≤ 0.15 | — |
| Bewelding-consumable restriction (AWS A5.10) | ≤ 8×10⁻⁴ | — |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
4047-O — frequently asked
What is 4047-O used for?
4047-O is typically used for brazing filler, heat exchangers, brazing sheet cladding layers, TIG/MIG filler wire for 3xx aluminum castings, vacuum and CAB brazed cold plates and radiator and condenser assemblies. In short: aluminum brazing filler (~12% Si); excellent fluidity.
What is the yield strength of 4047-O?
4047-O has a typical yield strength of 55 MPa (7.98 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 94% of aluminum grades. Strength varies by condition: see the 3 listed tempers.
Is 4047-O easy to machine?
Not especially — machinability is rated fair (35/100, worse than 86% of aluminum grades). Abrasive high-Si microstructure — use polished-flute carbide or PCD tooling, high speed, low feed and flood coolant; expect short tool life vs 6061.
Can 4047-O be welded?
Yes — weldability is rated excellent (92/100). This is the filler alloy itself: excellent fluidity and the lowest hot-cracking tendency of the Al-Si fillers, ideal for GTAW/GMAW of 3xx castings and Si-tolerant wrought alloys, but avoid on Mg-bearing 5xxx base metals (brittle Mg2Si) and where post-weld anodizing colour matters.
What surface finishes work on 4047-O?
Anodizes dark and blotchy; prefer chromate/chemical conversion coating, paint, or leave as-brazed; mechanical polishing pulls out Si particles.
Can 4047-O be formed, bent or molded?
Very high casting/brazing fluidity with minimal shrinkage; wrought forming is limited — cold bending of wire/foil only, no heat-treat strengthening available.
What is the maximum service temperature of 4047-O?
4047-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 4047-F and 4047-O?
F is the default condition — default stocked condition for 4047 welding wire, brazing rod, foil and brazing-sheet cladding — no controlled mechanical properties, chosen for melting behaviour rather than strength. O: pick when maximum ductility is needed for coiling, stamping of brazing foil, or roll-bonded clad sheet before the braze cycle. Yield strength is 70 MPa in F versus 55 MPa in O.
Can FabDigit make parts in 4047-O?
Yes — 4047-O is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
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)
- EN ISO 18273 — Welding consumables, wire electrodes and rods for aluminium and aluminium alloys (S Al 4047 / AlSi12) — ISO (2015)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B / Vol. 6 — Corrosion and Welding, Brazing and Soldering — ASM International (1993)
- Aluminium filler metal 4047 / AlSi12 datasheets — Various filler-metal 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.