Aluminum 249.0-T6
Temper
AA 249.0 · UNS A02490
T6 = solution heat treated and artificially aged
Use for maximum room-temperature strength where corrosion exposure is controlled by coatings.
Values for the T6 condition
Other 249.0 tempers and conditions
249.0 is listed in 5 conditions; see the grade overview at 249.0.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
As fabricated | As-cast, no heat treatment — only for non-structural parts or as an intermediate state before solution treatment. | 110 | 195 | 2.5 | 65 HB | 38 % IACS |
Solution heat treated and naturally aged | Pick when maximum ductility and toughness matter more than yield strength, or before further forming/straightening. | 200 | 330 | 12 | 85 HB | 29 % IACS |
T7Default Solution heat treated and overaged (stabilized) | Default aerospace condition: slightly lower strength than T6 but better dimensional stability, elevated-temperature retention and resistance to intergranular/stress-corrosion attack. | 345 | 415 | 5 | 110 HB | 33 % IACS |
T6This page Solution heat treated and artificially aged | Use for maximum room-temperature strength where corrosion exposure is controlled by coatings. | 380 | 440 | 4 | 125 HB | 31 % IACS |
T6, heat treated by the user | Foundry heat-treat variant giving the highest registered strength; choose for critical thin-wall aerospace castings with tight process control. | 415 | 470 | 3 | 135 HB | 32 % IACS |
What is 249.0-T6?
249.0-T6 is 249.0 in the T6 temper — use for maximum room-temperature strength where corrosion exposure is controlled by coatings. 249.0-T6 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 440 MPa (63.8 ksi) — stronger than 86% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi). 249.0-T6 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 540°C (1,004 °F). T7 is the default condition FabDigit quotes; T6 is available on request or by drawing note.
Advantages
- Easy to machine — 78/100, better than 89% of aluminum grades
- High strength — 380 MPa (55.1 ksi), better than 86% of aluminum grades
Limitations
- Needs corrosion protection — 30/100, worse than 98% of aluminum grades
- Poor heat conductor — 120 W/m·K (69.3 BTU/hr·ft·°F), worse than 80% of aluminum grades
- Difficult to weld — 25/100, worse than 76% of aluminum grades
249.0-T6 properties
Typical room-temperature values for 249.0-T6; 12 are specific to this condition. Other listed values are 249.0 reference data and may not represent this condition. Bars are the position among aluminum grades.
Physical3
249.0-T6 has a density of 2.81 g/cm³ (0.102 lb/in³), heavier than 86% of aluminum grades. It melts at 540°C (1,004 °F).
Mechanical12
249.0-T6 has a yield strength of 380 MPa (55.1 ksi) and a tensile strength of 440 MPa (63.8 ksi) — stronger than 86% of aluminum grades. Elongation at break is 4% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
249.0-T6 is rated for continuous service to 150°C (302 °F). It conducts heat at 120 W/m·K (69.3 BTU/hr·ft·°F), worse than 80% of aluminum grades. Thermal expansion is 22.8 µm/m·K (12.7 µin/in·°F).
Electrical3
249.0-T6 conducts electricity at 31 % IACS, worse than 68% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is poor (30/100), worse than 98% of aluminum grades.
Sustainability4
Producing a kilogram of 249.0-T6 takes about 200 MJ of energy and emits 12.5 kg of CO₂ — less than 60% of aluminum grades. Typical recycled content is 10%.
Manufacturability7
249.0-T6's machinability is very good (78/100, better than 89% of aluminum grades); weldability poor (25/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 249.0-T6
Is 249.0 easy to machine?
Machines well in T6/T7 with sharp carbide or PCD tools, high speeds and generous coolant; watch for porosity breakout on machined sealing faces.
Can 249.0 be welded?
Poor fusion weldability — Al-Cu castings are highly hot-crack sensitive; repair welding only by qualified procedure (2319-type filler) followed by re-solution/re-age.
Can 249.0 be formed, bent or molded?
Sand or permanent-mold cast with heavy chilling, directional solidification and strong risering; wide freezing range makes it prone to hot tearing and micro-shrinkage, HIP is often used on critical parts.
What surface finishes work on 249.0?
Chromic/sulfuric anodize gives only fair protection because of Cu-rich phases; standard aerospace practice is conversion coat plus epoxy primer and topcoat.
249.0 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 |
|---|---|---|
| Cuprincipal strengthening element | 3.8 – 4.6 | 4.2 |
| Znco-strengthener with Mg | 2.5 – 3.5 | 3 |
| Mg | 0.25 – 0.45 | 0.35 |
| Mndispersoid former, grain-structure control | 0.25 – 0.5 | 0.35 |
| Tigrain refiner | 0.05 – 0.25 | 0.15 |
| Siimpurity limit — high purity required | ≤ 0.05 | — |
| Feimpurity limit | ≤ 0.1 | — |
| Others (each) | ≤ 0.05 | — |
| Others (total) | ≤ 0.15 | — |
| Al | balance | — |
249.0-T6 — frequently asked
What is 249.0-T6 used for?
249.0-T6 is typically used for aerospace structural castings, high-temperature brackets and fittings, airframe fitting and hinge castings, highly loaded housings and gearbox cases, missile and actuator body castings and HIP-treated critical cast components. In short: highest-strength cast aluminum family; aerospace structural casting alloy; hot-crack sensitive, poor weldability.
What is the yield strength of 249.0-T6?
249.0-T6 has a typical yield strength of 380 MPa (55.1 ksi) and a tensile strength of 440 MPa (63.8 ksi) — stronger than 86% of aluminum grades. Strength varies by condition: see the 5 listed tempers.
Is 249.0-T6 easy to machine?
Yes — machinability is rated very good (78/100, better than 89% of aluminum grades). Machines well in T6/T7 with sharp carbide or PCD tools, high speeds and generous coolant; watch for porosity breakout on machined sealing faces.
Can 249.0-T6 be welded?
Not readily — weldability is rated poor (25/100). Poor fusion weldability — Al-Cu castings are highly hot-crack sensitive; repair welding only by qualified procedure (2319-type filler) followed by re-solution/re-age.
What surface finishes work on 249.0-T6?
Chromic/sulfuric anodize gives only fair protection because of Cu-rich phases; standard aerospace practice is conversion coat plus epoxy primer and topcoat.
Can 249.0-T6 be formed, bent or molded?
Sand or permanent-mold cast with heavy chilling, directional solidification and strong risering; wide freezing range makes it prone to hot tearing and micro-shrinkage, HIP is often used on critical parts.
What is the maximum service temperature of 249.0-T6?
249.0-T6 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 249.0-T7 and 249.0-F?
T7 is the default condition — default aerospace condition: slightly lower strength than T6 but better dimensional stability, elevated-temperature retention and resistance to intergranular/stress-corrosion attack. F: as-cast, no heat treatment — only for non-structural parts or as an intermediate state before solution treatment. Yield strength is 345 MPa in T7 versus 110 MPa in F.
Sources
- Registration Record of Aluminum Association Alloy Designations and Chemical Composition Limits for Aluminum Alloys in the Form of Castings and Ingot ('Pink Sheets') — The Aluminum Association (2018)
- ASTM B108 — Aluminum-Alloy Permanent Mold Castings — ASTM International (2019)
- ASTM B26/B26M — Aluminum-Alloy Sand Castings — ASTM International (2018)
- ASM Handbook Vol.2 — Properties and Selection: Nonferrous Alloys and Special-Purpose Materials — ASM International (1990)
- ASM Specialty Handbook: Aluminum and Aluminum Alloys — ASM International (1993)
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.