Aluminum 6061-T51
Temper
AA 6061 · UNS A96061 · EN AlMg1SiCu, AW-6061 · JIS A6061, A6061P · GB LD30
T51 = t5, stress relieved by stretching
Rarely stocked variant of T5 for rolled or extruded rod where only ageing is applied.
Values for the T51 condition
Other 6061 tempers and conditions
6061 is listed in 20 conditions; see the grade overview at 6061.
Compare all 20 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Pick for maximum formability (deep drawing, tight bends) before subsequent solution treatment and ageing. | 55 | 124 | 27 | 30 HB | 47 % IACS |
As fabricated | Hot-worked stock (extrusion, forging, rolled billet) bought for subsequent heat treatment; mechanical properties not guaranteed. | 90 | 170 | 22 | 45 HB | 47 % IACS |
Cooled from hot working and naturally aged | Occasionally supplied press-quenched extrusions of low strength intended for further forming or ageing. | 100 | 180 | 20 | 50 HB | 46 % IACS |
Solution heat treated and naturally aged by the user | Material re-solution-treated from O or F by the fabricator; specified when heat treatment happens after forming. | 140 | 250 | 22 | 65 HB | 40 % IACS |
As printed (laser powder-bed fusion / DED, no post-treatment) | As-built additively manufactured 6061 (often with grain-refining modifiers such as 6061-RAM2); anisotropic, hot-crack prone and normally heat treated before use. | 140 | 230 | 7 | 60 HB | 40 % IACS |
Solution heat treated and naturally aged | Choose when parts must be bent, drawn or roll-formed at medium strength and then optionally aged to T6. | 145 | 241 | 22 | 65 HB | 40 % IACS |
T4, stress relieved by stretching | Flat, low-residual-stress T4 plate for parts machined before ageing. | 145 | 241 | 20 | 65 HB | 40 % IACS |
T4 extrusion, stress relieved by stretching and minor straightening | Straight, low-stress T4 extrusions and drawn tube for machined parts aged after cutting. | 145 | 241 | 20 | 65 HB | 40 % IACS |
Stress relieved (thermal, AM or wrought) | Low-temperature thermal stress relief (typically ~300 °C) used on additively built or heavily machined parts; strength between annealed and T6. | 150 | 230 | 12 | 60 HB | 45 % IACS |
T51This page T5, stress relieved by stretching | Rarely stocked variant of T5 for rolled or extruded rod where only ageing is applied. | 225 | 255 | 12 | 82 HB | 44 % IACS |
Cooled from hot working and artificially aged | Economical press-quenched-and-aged extrusions where near-T6 strength with less distortion is acceptable. | 240 | 260 | 11 | 85 HB | 43 % IACS |
Hot isostatic pressed | Applied to additively built or cast 6061 to close porosity and lift ductility and fatigue life; usually followed by a T6 ageing cycle. | 250 | 290 | 11 | 90 HB | 43 % IACS |
T6, heat treated by the user | Specify when O/F material is formed first and given the full T6 cycle by the fabricator; slightly lower guaranteed properties than mill T6. | 265 | 305 | 11 | 93 HB | 43 % IACS |
T6, stress relieved by compression | Hand and die forgings needing dimensional stability during heavy machining. | 275 | 305 | 10 | 95 HB | 43 % IACS |
T6Default Solution heat treated and artificially aged | Default choice: peak-strength general engineering temper for machined parts, frames, fixtures and structural extrusions. | 276 | 310 | 12 | 95 HB | 43 % IACS |
T6, stress relieved by stretching | The standard plate temper for precision machined parts and mould/jig plate: T6 strength with low residual stress and minimal warping. | 276 | 310 | 11 | 95 HB | 43 % IACS |
T6, stress relieved by stretching, minor straightening | The usual temper for straight, low-stress 6061 bar, rod and tube destined for CNC machining. | 276 | 310 | 10 | 95 HB | 43 % IACS |
T6 extrusion, stress relieved by stretching, no straightening | Low-residual-stress T6 extrusions and drawn tube where post-stretch straightening is not permitted. | 276 | 310 | 10 | 95 HB | 43 % IACS |
Solution heat treated, cold worked, artificially aged | High-strength thermomechanical temper for 6061 rod/bar/wire: solution treated, cold worked, then artificially aged, giving roughly 15–20 % more strength than T6 with reduced ductility and formability. | 386 | 405 | 12 | 110 HB | 42 % IACS |
Solution heat treated, artificially aged, cold worked | Peak-strength cold-finished temper for 6061 bar/wire: aged to T6 and then cold worked, delivering the highest 6061 strength level at low elongation and poor cold formability. | 414 | 434 | 12 | 116 HB | 42 % IACS |
What is 6061-T51?
6061-T51 is 6061 in the T51 temper — rarely stocked variant of T5 for rolled or extruded rod where only ageing is applied. 6061-T51 has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Elongation at break is 12% and the elastic modulus is 68.9 GPa (9.99 Msi). 6061-T51 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 582°C (1,080 °F). T6 is the default condition FabDigit quotes; T51 is available on request or by drawing note.
Advantages
- High electrical conductivity — 44 % IACS, better than 85% of aluminum grades
- Conducts heat well — 167 W/m·K (96.5 BTU/hr·ft·°F), better than 81% of aluminum grades
- High service temperature — 170°C (338 °F), better than 80% of aluminum grades
- Readily welded — 85/100, better than 79% of aluminum grades
- Tough — resists crack growth — 30 MPa·√m (27.3 ksi·√in), better than 76% of aluminum grades
6061-T51 properties
Typical room-temperature values for 6061-T51; 21 are specific to this condition. Other listed values are 6061 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6061-T51 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 582°C (1,080 °F).
Mechanical16
6061-T51 has a yield strength of 225 MPa (32.6 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Elongation at break is 12% and the elastic modulus is 68.9 GPa (9.99 Msi).
Thermal6
6061-T51 is rated for continuous service to 170°C (338 °F). It conducts heat at 167 W/m·K (96.5 BTU/hr·ft·°F), better than 81% of aluminum grades. Thermal expansion is 23.6 µm/m·K (13.1 µin/in·°F).
Electrical3
6061-T51 conducts electricity at 44 % IACS, better than 85% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (55/100), worse than 51% of aluminum grades.
Sustainability4
Producing a kilogram of 6061-T51 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 35%.
Manufacturability6
6061-T51's machinability is good (68/100, better than 67% of aluminum grades); weldability excellent (85/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6061-T51
Is 6061 easy to machine?
Machines very well in T6/T651 with polished-flute carbide, high speed and air/mist or flood coolant; annealed or T4 material is gummy and builds up on the edge.
Can 6061 be welded?
Readily GTAW/GMAW/FSW welded — use 4043 for crack resistance or 5356 for higher weld ductility/anodizing match; expect HAZ strength to drop to roughly T4 levels unless the part is re-solutionised and aged.
Can 6061 be formed, bent or molded?
Form, bend and draw in O or T4 and age afterwards; T6 tolerates only generous bend radii (≈4–6 t) and is prone to cracking on tight bends. Extrudes and forges easily at 375–500 °C.
What surface finishes work on 6061?
Excellent for clear, colour and Type III hard anodizing (expect a slight grey cast), chromate/Ti-Zr conversion coating, powder coat and paint; bright polishing is limited by second-phase particles, and electroless nickel or zincate-plus-electroplate is used for plating.
6061 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 – 0.8 | 0.6 |
| Feimpurity limit | ≤ 0.7 | 0.35 |
| Cu | 0.15 – 0.4 | 0.28 |
| Mn | ≤ 0.15 | 0.05 |
| Mgforms Mg2Si strengthening precipitates | 0.8 – 1.2 | 1 |
| Crgrain control, SCC resistance | 0.04 – 0.35 | 0.2 |
| Zn | ≤ 0.25 | 0.05 |
| Ti | ≤ 0.15 | 0.05 |
| Others (each)total 0.15 max | ≤ 0.05 | — |
| Alremainder, ~95.8–98.6 % | balance | — |
6061-T51 — frequently asked
What is 6061-T51 used for?
6061-T51 is typically used for general CNC machined parts, aerospace and structural brackets, hydraulic manifolds and valve bodies, machine frames and extruded structural profiles, robotics and automation components and tooling plate and jig fixtures. In short: the go-to general purpose; versatile.
What is the yield strength of 6061-T51?
6061-T51 has a typical yield strength of 225 MPa (32.6 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Strength varies by condition: see the 20 listed tempers.
Is 6061-T51 easy to machine?
Reasonably — machinability is rated good (68/100, better than 67% of aluminum grades). Machines very well in T6/T651 with polished-flute carbide, high speed and air/mist or flood coolant; annealed or T4 material is gummy and builds up on the edge.
Can 6061-T51 be welded?
Yes — weldability is rated excellent (85/100). Readily GTAW/GMAW/FSW welded — use 4043 for crack resistance or 5356 for higher weld ductility/anodizing match; expect HAZ strength to drop to roughly T4 levels unless the part is re-solutionised and aged.
What surface finishes work on 6061-T51?
Excellent for clear, colour and Type III hard anodizing (expect a slight grey cast), chromate/Ti-Zr conversion coating, powder coat and paint; bright polishing is limited by second-phase particles, and electroless nickel or zincate-plus-electroplate is used for plating.
Can 6061-T51 be formed, bent or molded?
Form, bend and draw in O or T4 and age afterwards; T6 tolerates only generous bend radii (≈4–6 t) and is prone to cracking on tight bends. Extrudes and forges easily at 375–500 °C.
What is the maximum service temperature of 6061-T51?
6061-T51 is rated for continuous use to about 170°C (338 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 6061-T6 and 6061-O?
T6 is the default condition — default choice: peak-strength general engineering temper for machined parts, frames, fixtures and structural extrusions. O: pick for maximum formability (deep drawing, tight bends) before subsequent solution treatment and ageing. Yield strength is 276 MPa in T6 versus 55 MPa in O.
Can FabDigit make parts in 6061-T51?
Yes — 6061-T51 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
- 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)
- ASTM B221 — Aluminum and Aluminum-Alloy Extruded Bars, Rods, Wire, Profiles and Tubes — ASTM International (2021)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- MMPDS-17 — Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- EN 573-3 / EN 485-2 — EN AW-6061 (AlMg1SiCu) — CEN (2019)
- 6061 alloy technical datasheets (Alcoa / Constellium / Kaiser) — 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.