Aluminum 5556-O (Annealed)
Temper
AA 5556 · UNS A95556 · EN AW-5556, AlMg5Mn1Zr
Pick for straight cut-length TIG filler rod and redraw stock where softness and straightening ease matter more than stiffness.
Values for the O condition
Other 5556 tempers and conditions
5556 is listed in 4 conditions; see the grade overview at 5556.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
OThis page Annealed | Pick for straight cut-length TIG filler rod and redraw stock where softness and straightening ease matter more than stiffness. | 150 | 300 | 24 | 70 HB | 29.5 % IACS |
AWDefault As-welded deposit | Pick for design of GMAW/GTAW joints made with ER5556/R5556 — the condition in which this alloy is actually used. | 160 | 305 | 20 | 75 HB | 29 % IACS |
As fabricated | Mill intermediate condition of extruded rod before drawing; specified only when buying semi-finished wire stock. | 175 | 310 | 16 | 75 HB | 29 % IACS |
Strain hardened, half hard | The as-supplied drawn temper for spooled 0.8–2.4 mm MIG wire, stiff enough for reliable feeding through long liners. | 275 | 345 | 7 | 88 HB | 28 % IACS |
What is 5556-O?
5556-O is 5556 in the O temper — pick for straight cut-length TIG filler rod and redraw stock where softness and straightening ease matter more than stiffness. 5556-O has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 65% of aluminum grades. Elongation at break is 24% and the elastic modulus is 71 GPa (10.3 Msi). 5556-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 568°C (1,054 °F). AW is the default condition FabDigit quotes; O is available on request or by drawing note.
Advantages
- Readily welded — 94/100, better than 98% of aluminum grades
- Good corrosion resistance — 78/100, better than 94% of aluminum grades
- Ductile — tolerates forming and impact — 24%, better than 92% of aluminum grades
- Forms and bends easily — 65/100, better than 80% of aluminum grades
Limitations
- Limited service temperature — 65°C (149 °F), worse than 97% of aluminum grades
- Poor heat conductor — 113 W/m·K (65.3 BTU/hr·ft·°F), worse than 86% of aluminum grades
- Difficult to machine — 40/100, worse than 81% of aluminum grades
- Low electrical conductivity — 29.5 % IACS, worse than 75% of aluminum grades
5556-O properties
Typical room-temperature values for 5556-O; 22 are specific to this condition. Other listed values are 5556 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
5556-O has a density of 2.66 g/cm³ (0.0961 lb/in³), lighter than 84% of aluminum grades. It melts at 568°C (1,054 °F).
Mechanical10
5556-O has a yield strength of 150 MPa (21.8 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 65% of aluminum grades. Elongation at break is 24% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
5556-O is rated for continuous service to 65°C (149 °F). It conducts heat at 113 W/m·K (65.3 BTU/hr·ft·°F), worse than 86% of aluminum grades. Thermal expansion is 24.2 µm/m·K (13.4 µin/in·°F).
Electrical3
5556-O conducts electricity at 29.5 % IACS, worse than 75% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is very good (78/100), better than 94% of aluminum grades.
Sustainability4
Producing a kilogram of 5556-O takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 15%.
Manufacturability8
5556-O's machinability is fair (40/100, worse than 81% of aluminum grades); weldability excellent (94/100); formability good (65/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 5556-O
Is 5556 easy to machine?
Machines like 5083/5456 — gummy and adherent; use sharp polished carbide, high rake, high speed and flood coolant to avoid built-up edge (rarely machined, mostly consumed as filler).
Can 5556 be welded?
Designed as GMAW/GTAW filler for 5083/5456/5456-type and armor plate; run with 100 % Ar (or Ar-He), keep interpass temperature low, and never use on parts serving above ~65 °C.
Can 5556 be formed, bent or molded?
Supplied by hot extrusion plus multi-pass cold drawing with interpass anneals; drawn wire work-hardens fast and needs good surface cleanliness for arc stability.
What surface finishes work on 5556?
Anodizes and paints well after alkaline etch/desmut, but high-Mg weld metal anodizes darker than 6000-series base, so color matching is poor; do not attempt conventional brazing or dip soldering.
5556 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 |
|---|---|---|
| Si | ≤ 0.25 | 0.1 |
| Fe | ≤ 0.4 | 0.2 |
| Cu | ≤ 0.1 | 0.02 |
| Mn | 0.5 – 1 | 0.75 |
| Mg | 4.7 – 5.5 | 5.1 |
| Cr | 0.05 – 0.2 | 0.12 |
| Zn | ≤ 0.25 | 0.05 |
| Tigrain refiner | 0.05 – 0.2 | 0.12 |
| Zronly in the EN AW-5556A (AlMg5Mn1Zr) variant; not required by AA 5556 | 0.1 – 0.2 | 0.15 |
| Berestricted/omitted in current AWS A5.10 revisions (fume toxicity) | ≤ 3×10⁻⁴ | — |
| Others (each)0.15 total | ≤ 0.05 | — |
| Al | balance | — |
5556-O — frequently asked
What is 5556-O used for?
5556-O is typically used for structural welding, military vehicle fabrication and high-strength marine welds. In short: strongest common 5000-series filler; stronger welds than 5356; ambient-service joints only.
What is the yield strength of 5556-O?
5556-O has a typical yield strength of 150 MPa (21.8 ksi) and a tensile strength of 300 MPa (43.5 ksi) — weaker than 65% of aluminum grades. Strength varies by condition: see the 4 listed tempers.
Is 5556-O easy to machine?
Not especially — machinability is rated fair (40/100, worse than 81% of aluminum grades). Machines like 5083/5456 — gummy and adherent; use sharp polished carbide, high rake, high speed and flood coolant to avoid built-up edge (rarely machined, mostly consumed as filler).
Can 5556-O be welded?
Yes — weldability is rated excellent (94/100). Designed as GMAW/GTAW filler for 5083/5456/5456-type and armor plate; run with 100 % Ar (or Ar-He), keep interpass temperature low, and never use on parts serving above ~65 °C.
What surface finishes work on 5556-O?
Anodizes and paints well after alkaline etch/desmut, but high-Mg weld metal anodizes darker than 6000-series base, so color matching is poor; do not attempt conventional brazing or dip soldering.
Can 5556-O be formed, bent or molded?
Supplied by hot extrusion plus multi-pass cold drawing with interpass anneals; drawn wire work-hardens fast and needs good surface cleanliness for arc stability.
What is the maximum service temperature of 5556-O?
5556-O is rated for continuous use to about 65°C (149 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 5556-AW and 5556-H14?
AW is the default condition — pick for design of GMAW/GTAW joints made with ER5556/R5556 — the condition in which this alloy is actually used. H14: the as-supplied drawn temper for spooled 0.8–2.4 mm MIG wire, stiff enough for reliable feeding through long liners. Yield strength is 160 MPa in AW versus 275 MPa in H14.
Sources
- AWS A5.10/A5.10M — Specification for Bare Aluminum and Aluminum-Alloy Welding Electrodes and Rods — AWS (2021)
- International Alloy Designation and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN ISO 18273 — Welding consumables, wire and rods for fusion welding of aluminium and aluminium alloys — CEN/ISO (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B / Vol. 6 — Corrosion and Welding, Brazing & Soldering — ASM International (2005)
- AWS D1.2/D1.2M — Structural Welding Code, Aluminum — AWS (2014)
- ER5556 / R5556 aluminum filler metal datasheets — Lincoln Electric / ESAB / Hobart (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.