Aluminum 6003-T66
Precip hard
AA 6003 · UNS A96003 · EN AW-6003, AlMg1Si0.5Cu
T66 = t6 with improved mechanical properties
Controlled-practice ageing giving the highest guaranteed strength for structural window/door sections.
Values for the T66 condition
Other 6003 tempers and conditions
6003 is listed in 8 conditions; see the grade overview at 6003.
Compare all 8 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Annealed | Softest, most formable condition for severe bending or deep drawing before ageing. | 55 | 115 | 26 | 30 HB | 50 % IACS |
As fabricated | Mill/as-extruded state with no property guarantee; used when the part will be heat treated or is non-structural. | 85 | 150 | 18 | 45 HB | 47 % IACS |
Cooled from hot working and naturally aged | Press-quench-free profiles that will be bent or joined then optionally aged; low-cost intermediate strength. | 95 | 170 | 18 | 50 HB | 43 % IACS |
Solution heat treated and naturally aged | Formable pre-aged condition for profiles that must be bent or stretch-formed, then artificially aged to T6. | 100 | 185 | 20 | 55 HB | 41 % IACS |
Cooled from hot working and artificially aged | The economical architectural temper: press-quenched and aged, good strength with minimal distortion. | 170 | 205 | 12 | 65 HB | 47 % IACS |
T6 variant, underaged | Slightly under-aged T6 when profiles must still be bent or roll-formed after ageing. | 180 | 220 | 13 | 70 HB | 44 % IACS |
T6Default Solution heat treated and artificially aged | Default full-strength condition for structural window, door and framing profiles. | 205 | 240 | 10 | 75 HB | 45 % IACS |
T66This page T6 with improved mechanical properties | Controlled-practice ageing giving the highest guaranteed strength for structural window/door sections. | 220 | 255 | 8 | 80 HB | 46 % IACS |
What is 6003-T66?
6003-T66 is 6003 in the T66 condition — controlled-practice ageing giving the highest guaranteed strength for structural window/door sections. 6003-T66 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Elongation at break is 8% and the elastic modulus is 69 GPa (10 Msi). 6003-T66 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 615°C (1,139 °F). T6 is the default condition FabDigit quotes; T66 is available on request or by drawing note.
Advantages
- High electrical conductivity — 46 % IACS, better than 87% of aluminum grades
- Conducts heat well — 178 W/m·K (102.8 BTU/hr·ft·°F), better than 86% of aluminum grades
- Polishes to a fine finish — 65/100, better than 82% of aluminum grades
- Good corrosion resistance — 68/100, better than 75% of aluminum grades
6003-T66 properties
Typical room-temperature values for 6003-T66; 22 are specific to this condition. Other listed values are 6003 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
6003-T66 has a density of 2.7 g/cm³ (0.0975 lb/in³), lighter than 59% of aluminum grades. It melts at 615°C (1,139 °F).
Mechanical13
6003-T66 has a yield strength of 220 MPa (31.9 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Elongation at break is 8% and the elastic modulus is 69 GPa (10 Msi).
Thermal6
6003-T66 is rated for continuous service to 150°C (302 °F). It conducts heat at 178 W/m·K (102.8 BTU/hr·ft·°F), better than 86% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
6003-T66 conducts electricity at 46 % IACS, better than 87% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is good (68/100), better than 75% of aluminum grades.
Sustainability4
Producing a kilogram of 6003-T66 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
6003-T66's machinability is fair (52/100, worse than 63% of aluminum grades); weldability very good (78/100); formability fair (45/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 6003-T66
Is 6003 easy to machine?
Machines like 6061-T6 but slightly gummier in T5; use polished-flute carbide, high rake, 300–1000 m/min and flood or MQL to avoid built-up edge.
Can 6003 be welded?
Readily GMAW/GTAW welded with ER4043 (crack-safe) or ER5356 (colour-match for anodizing); expect HAZ strength to fall to about T4 level unless re-aged.
Can 6003 be formed, bent or molded?
Extrudes at moderate press speeds with press quenching to T5; bend in O/T4/T61 where possible — T6 needs bend radii of roughly 3–4× thickness.
What surface finishes work on 6003?
Excellent clear and colour anodizing and electrophoretic/powder coating for architectural service; mechanical polishing is fair — the Mn/Fe intermetallics can streak on bright-dip.
6003 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 | 0.35 – 1 | 0.7 |
| Feimpurity limit | ≤ 0.6 | 0.25 |
| Cu | ≤ 0.1 | 0.03 |
| Mn | ≤ 0.8 | 0.15 |
| Mg | 0.8 – 1.5 | 1.1 |
| Cr | ≤ 0.35 | 0.05 |
| Zn | ≤ 0.2 | 0.05 |
| Tigrain refiner | ≤ 0.1 | 0.02 |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
6003-T66 — frequently asked
What is 6003-T66 used for?
6003-T66 is typically used for window and door frames, structural profiles, ladders and railings. In short: stronger than 6060 extrusions; good architectural anodizing; balanced strength and formability.
What is the yield strength of 6003-T66?
6003-T66 has a typical yield strength of 220 MPa (31.9 ksi) and a tensile strength of 255 MPa (37 ksi) — stronger than 59% of aluminum grades. Strength varies by condition: see the 8 listed tempers.
Is 6003-T66 easy to machine?
Reasonably — machinability is rated fair (52/100, worse than 63% of aluminum grades). Machines like 6061-T6 but slightly gummier in T5; use polished-flute carbide, high rake, 300–1000 m/min and flood or MQL to avoid built-up edge.
Can 6003-T66 be welded?
Yes — weldability is rated very good (78/100). Readily GMAW/GTAW welded with ER4043 (crack-safe) or ER5356 (colour-match for anodizing); expect HAZ strength to fall to about T4 level unless re-aged.
What surface finishes work on 6003-T66?
Excellent clear and colour anodizing and electrophoretic/powder coating for architectural service; mechanical polishing is fair — the Mn/Fe intermetallics can streak on bright-dip.
Can 6003-T66 be formed, bent or molded?
Extrudes at moderate press speeds with press quenching to T5; bend in O/T4/T61 where possible — T6 needs bend radii of roughly 3–4× thickness.
What is the maximum service temperature of 6003-T66?
6003-T66 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 6003-T6 and 6003-O?
T6 is the default condition — default full-strength condition for structural window, door and framing profiles. O: softest, most formable condition for severe bending or deep drawing before ageing. Yield strength is 205 MPa in T6 versus 55 MPa in O.
Sources
- International Alloy Designations and Chemical Composition Limits for Wrought Aluminum (Teal Sheets) — The Aluminum Association (2018)
- EN 573-3 / EN 755-2 — Aluminium and aluminium alloys: chemical composition and mechanical properties of extruded rod/bar, tube and profiles — CEN (2016)
- ASM Handbook Vol. 2 — Properties and Selection: Nonferrous Alloys — ASM International (1990)
- ASM Handbook Vol. 13B — Corrosion: Materials — ASM International (2005)
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.