Aluminum 6081 · temper
Aluminum 6081-O
Properties of the O condition, compared with the other 6081 tempers.
Pick for maximum formability before subsequent solution treatment and ageing.
What is 6081-O?
6081-O is 6081 in the O temper — pick for maximum formability before subsequent solution treatment and ageing. 6081-O has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 92% of aluminum grades. Elongation at break is 24% and the elastic modulus is 69 GPa (10 Msi). 6081-O has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 60% of aluminum grades. It melts at 585°C (1,085 °F).
Advantages
- Forms and bends easily — 90/100, better than 93% of aluminum grades
- Ductile — tolerates forming and impact — 24%, better than 92% of aluminum grades
- High service temperature — 200°C (392 °F), better than 90% of aluminum grades
- High electrical conductivity — 50 % IACS, better than 90% of aluminum grades
- Conducts heat well — 185 W/m·K (106.9 BTU/hr·ft·°F), better than 87% of aluminum grades
Limitations
- Low strength — 65 MPa (9.43 ksi), worse than 92% of aluminum grades
- Difficult to machine — 35/100, worse than 86% of aluminum grades
6081-O properties
Typical room-temperature values for 6081-O — 15 properties are specific to this condition; the rest are grade-level values shared by every 6081 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
6081-O has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 60% of aluminum grades. It melts at 585°C (1,085 °F).
Mechanical13
6081-O has a yield strength of 65 MPa (9.43 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 92% of aluminum grades. Elongation at break is 24% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6081-O is rated for continuous service to 200°C (392 °F). It conducts heat at 185 W/m·K (106.9 BTU/hr·ft·°F), better than 87% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6081-O conducts electricity at 50 % IACS, better than 90% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 75% of aluminum grades.
Sustainability4
Producing a kilogram of 6081-O takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability8
6081-O's machinability is fair (35/100, worse than 86% of aluminum grades); weldability very good (80/100); formability excellent (90/100).
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 6081 tempers and conditions
6081 is also supplied in 6 other conditions. The full side-by-side table is on the 6081 overview.
- T6Default structural condition: highest strength with good corrosion resistance and anodizing quality.275 MPa yield · 95 HB
- T5Pick for thin-wall press-quenched profiles where slightly lower strength than T6 is acceptable and distortion must be minimised.230 MPa yield · 85 HB
- T4Pick when parts must still be bent, stretched or roll-formed after solution treatment, then optionally aged to T6.115 MPa yield · 62 HB
- OPick for maximum formability before subsequent solution treatment and ageing.65 MPa yield · 30 HB
Working with 6081-O
Is 6081 easy to machine?
Machines cleanly in T5/T6 with polished-flute carbide, high speed and >0.1 mm/tooth feed plus coolant to avoid built-up edge; avoid machining in O/T4 (gummy).
Can 6081 be welded?
Good MIG/TIG and friction-stir weldability with ER5356 (strength/marine) or ER4043 (crack resistance); HAZ drops to roughly T4 strength unless post-weld aged.
Can 6081 be formed, bent or molded?
Extrudes faster than 6082 thanks to low Mn/Cr; do tight bends in O or T4 and age afterwards, T6 tolerates only generous bend radii.
What surface finishes work on 6081?
Takes clear and colour anodizing well and accepts chromate-free pretreatment, powder coat and paint; use a chemical bright dip for decorative work as Si/Mn slightly grey the finish.
6081 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 |
|---|---|---|
| Simain strengthening partner with Mg (Mg2Si) | 0.7 – 1.1 | 0.9 |
| Fe | ≤ 0.5 | 0.25 |
| Cukept low for corrosion resistance | ≤ 0.1 | 0.03 |
| Mngrain-structure control | 0.1 – 0.45 | 0.25 |
| Mg | 0.6 – 1 | 0.8 |
| Cr | ≤ 0.1 | 0.03 |
| Zn | ≤ 0.2 | 0.05 |
| Ti | ≤ 0.15 | 0.02 |
| Others (each)total others 0.15 max | ≤ 0.05 | — |
| Al | balance | — |
6081-O — frequently asked
What is 6081-O used for?
6081-O is typically used for rail car structural profiles, automotive structural extrusions, architectural extrusions, scaffolding tubes and planks, general load-bearing profiles and welded frame assemblies. In short: extrusion grade like 6005A.
What is the yield strength of 6081-O?
6081-O has a typical yield strength of 65 MPa (9.43 ksi) and a tensile strength of 130 MPa (18.9 ksi) — weaker than 92% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 6081-O easy to machine?
Not especially — machinability is rated fair (35/100, worse than 86% of aluminum grades). Machines cleanly in T5/T6 with polished-flute carbide, high speed and >0.1 mm/tooth feed plus coolant to avoid built-up edge; avoid machining in O/T4 (gummy).
Can 6081-O be welded?
Yes — weldability is rated very good (80/100). Good MIG/TIG and friction-stir weldability with ER5356 (strength/marine) or ER4043 (crack resistance); HAZ drops to roughly T4 strength unless post-weld aged.
What surface finishes work on 6081-O?
Takes clear and colour anodizing well and accepts chromate-free pretreatment, powder coat and paint; use a chemical bright dip for decorative work as Si/Mn slightly grey the finish.
Can 6081-O be formed, bent or molded?
Extrudes faster than 6082 thanks to low Mn/Cr; do tight bends in O or T4 and age afterwards, T6 tolerates only generous bend radii.
What is the maximum service temperature of 6081-O?
6081-O is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Can FabDigit make parts in 6081-O?
Yes — 6081-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
- EN 573-3 Aluminium and aluminium alloys — chemical composition of wrought products — CEN (2019)
- EN 755-2 Aluminium and aluminium alloys — extruded rod/bar, tube and profiles: mechanical properties — CEN (2016)
- 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)
- EN 1999-1-1 Eurocode 9: Design of aluminium structures — CEN (2007)
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.