Aluminum 6261-T651
Temper
AA 6261 · UNS A96261 · EN AlMg1SiCuMn
T651 = t6, stress relieved by stretching
Specify when machined parts must stay dimensionally stable after heavy stock removal from plate or heavy extrusions.
Values for the T651 condition
Other 6261 tempers and conditions
6261 is listed in 9 conditions; see the grade overview at 6261.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum formability before a later solution treat and age; not a structural condition. | 65 | 130 | 25 | 32 HB | 49 % IACS |
Slightly strain hardened | Soft mill/extruded condition with incidental work hardening from handling or straightening; used where the part will be formed then heat treated. | 85 | 150 | 20 | 38 HB | 48 % IACS |
Solution heat treated and naturally aged | Choose when bending, stretch-forming or roll-forming is needed after heat treatment, with a later T6-type ageing to recover strength. | 140 | 250 | 18 | 68 HB | 39 % IACS |
Solution treated, naturally aged, stress-relieved by stretching | Straight, low-residual-stress bar/tube in the formable T4 state for later forming and ageing. | 140 | 245 | 17 | 67 HB | 40 % IACS |
Cooled from hot working and artificially aged | Economical press-quenched temper for thin-wall profiles where full T6 strength and straightness after solution treatment are not required. | 250 | 290 | 8 | 90 HB | 44 % IACS |
T651This page T6, stress relieved by stretching | Specify when machined parts must stay dimensionally stable after heavy stock removal from plate or heavy extrusions. | 295 | 325 | 10 | 98 HB | 43 % IACS |
Solution treated, stretch stress-relieved, artificially aged | Precision extruded bar/profile for machined structural parts where distortion must be minimised. | 295 | 325 | 10 | 98 HB | 43 % IACS |
T6Default Solution heat treated and artificially aged | Standard structural condition for 6261 — the reason to specify this alloy over 6061/6082; use for load-bearing tubes, scaffolding and framing. | 300 | 330 | 10 | 100 HB | 43 % IACS |
T6 with improved mechanical properties | European extruder temper giving slightly higher guaranteed proof strength than T6 with controlled ageing; used for scaffolding and access towers. | 315 | 345 | 9 | 105 HB | 43 % IACS |
What is 6261-T651?
6261-T651 is 6261 in the T651 temper — specify when machined parts must stay dimensionally stable after heavy stock removal from plate or heavy extrusions. 6261-T651 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 325 MPa (47.1 ksi) — stronger than 75% of aluminum grades. Elongation at break is 10% and the elastic modulus is 70 GPa (10.2 Msi). 6261-T651 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 585°C (1,085 °F). T6 is the default condition FabDigit quotes; T651 is available on request or by drawing note.
Advantages
- High electrical conductivity — 43 % IACS, better than 83% of aluminum grades
- Conducts heat well — 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades
- High strength — 295 MPa (42.8 ksi), better than 75% of aluminum grades
6261-T651 properties
Typical room-temperature values for 6261-T651; 21 are specific to this condition. Other listed values are 6261 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6261-T651 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 585°C (1,085 °F).
Mechanical13
6261-T651 has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 325 MPa (47.1 ksi) — stronger than 75% of aluminum grades. Elongation at break is 10% and the elastic modulus is 70 GPa (10.2 Msi).
Thermal6
6261-T651 is rated for continuous service to 150°C (302 °F). It conducts heat at 170 W/m·K (98.2 BTU/hr·ft·°F), better than 82% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6261-T651 conducts electricity at 43 % IACS, better than 83% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (63/100), better than 69% of aluminum grades.
Sustainability4
Producing a kilogram of 6261-T651 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
6261-T651's machinability is good (58/100, worse than 54% of aluminum grades); weldability good (68/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6261-T651
Is 6261 easy to machine?
Machines like 6061-T6: high speeds, polished-flute carbide, 3-flute cutters and coolant/lubricant to avoid built-up edge; gummy in O/T4.
Can 6261 be welded?
Readily GMAW/GTAW welded with ER4043 (crack resistance) or ER5356 (strength/anodizing match); expect HAZ strength down toward T4 levels unless post-weld solution treat and age.
Can 6261 be formed, bent or molded?
Extrudes and roll-forms well in O/T4; in T6 keep bend radii ≥3–4 t and avoid tight reverse bends — springback is high.
What surface finishes work on 6261?
Anodizes well (clear and hard coat) though the Cu content can darken clear films slightly; also takes chromate/anodic pretreat plus powder coat, and polishes to a satin finish.
6261 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 | 0.4 – 0.7 | 0.55 |
| Feimpurity limit | ≤ 0.4 | 0.2 |
| Curaises strength, slightly lowers corrosion margin | 0.15 – 0.4 | 0.27 |
| Mngrain/recrystallisation control | 0.2 – 0.35 | 0.28 |
| Mg | 0.7 – 1 | 0.85 |
| Cr | ≤ 0.1 | — |
| Zn | ≤ 0.2 | — |
| Ti | ≤ 0.1 | — |
| Others (each)0.15 % total | ≤ 0.05 | — |
| Al | balance | — |
6261-T651 — frequently asked
What is 6261-T651 used for?
6261-T651 is typically used for marine structural sections, transport frames and structural extrusions. In short: stronger than 6061-T6; weldable structural extrusion; marine and transport 6000 series.
What is the yield strength of 6261-T651?
6261-T651 has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 325 MPa (47.1 ksi) — stronger than 75% of aluminum grades. Strength varies by condition: see the 9 listed tempers.
Is 6261-T651 easy to machine?
Reasonably — machinability is rated good (58/100, worse than 54% of aluminum grades). Machines like 6061-T6: high speeds, polished-flute carbide, 3-flute cutters and coolant/lubricant to avoid built-up edge; gummy in O/T4.
Can 6261-T651 be welded?
Yes — weldability is rated good (68/100). Readily GMAW/GTAW welded with ER4043 (crack resistance) or ER5356 (strength/anodizing match); expect HAZ strength down toward T4 levels unless post-weld solution treat and age.
What surface finishes work on 6261-T651?
Anodizes well (clear and hard coat) though the Cu content can darken clear films slightly; also takes chromate/anodic pretreat plus powder coat, and polishes to a satin finish.
Can 6261-T651 be formed, bent or molded?
Extrudes and roll-forms well in O/T4; in T6 keep bend radii ≥3–4 t and avoid tight reverse bends — springback is high.
What is the maximum service temperature of 6261-T651?
6261-T651 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 6261-T6 and 6261-O?
T6 is the default condition — standard structural condition for 6261 — the reason to specify this alloy over 6061/6082; use for load-bearing tubes, scaffolding and framing. O: pick for maximum formability before a later solution treat and age; not a structural condition. Yield strength is 300 MPa in T6 versus 65 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 755-2 Aluminium and aluminium alloys — Extruded rod/bar, tube and profiles — Mechanical properties — CEN (2016)
- EN 573-3 Chemical composition of wrought aluminium products — CEN (2019)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B: Corrosion — Materials — ASM International (2005)
- Extruded 6000-series structural profile datasheets (scaffolding/transport tempers T5/T6/T66) — European extruders (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.