Aluminum 7040 · temper · default condition
Aluminum 7040-T7451
Properties of the T7451 condition, compared with the other 7040 tempers.
The standard supply condition for 7040 aerospace thick plate: near-T6 strength with good through-thickness toughness, SCC resistance and low residual stress for deep machining.
What is 7040-T7451?
7040-T7451 is 7040 in the T7451 temper — the standard supply condition for 7040 aerospace thick plate: near-T6 strength with good through-thickness toughness, SCC resistance and low residual stress for deep machining. 7040-T7451 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 505 MPa (73.2 ksi) — stronger than 91% of aluminum grades. Elongation at break is 10% and the elastic modulus is 71 GPa (10.3 Msi). 7040-T7451 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 480°C (896 °F).
Advantages
- Tough — resists crack growth — 38 MPa·√m (34.6 ksi·√in), better than 96% of aluminum grades
- High strength — 450 MPa (65.3 ksi), better than 91% of aluminum grades
- High electrical conductivity — 40.5 % IACS, better than 77% of aluminum grades
Limitations
- Difficult to weld — 20/100, worse than 89% of aluminum grades
- Limited service temperature — 120°C (248 °F), worse than 79% of aluminum grades
7040-T7451 properties
Typical room-temperature values for 7040-T7451 — 16 properties are specific to this condition; the rest are grade-level values shared by every 7040 temper. Each bar shows where the value sits among the aluminum grades in FabDigit's library — further right is higher.
Physical3
7040-T7451 has a density of 2.82 g/cm³ (0.102 lb/in³), heavier than 89% of aluminum grades. It melts at 480°C (896 °F).
Mechanical12
7040-T7451 has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 505 MPa (73.2 ksi) — stronger than 91% of aluminum grades. Elongation at break is 10% and the elastic modulus is 71 GPa (10.3 Msi).
Thermal6
7040-T7451 is rated for continuous service to 120°C (248 °F). It conducts heat at 154 W/m·K (89 BTU/hr·ft·°F), better than 68% of aluminum grades. Thermal expansion is 23.4 µm/m·K (13 µin/in·°F).
Electrical3
7040-T7451 conducts electricity at 40.5 % IACS, better than 77% of aluminum grades.
Chemical & Environmental3
Corrosion resistance is fair (45/100), worse than 62% of aluminum grades.
Sustainability4
Producing a kilogram of 7040-T7451 takes about 205 MJ of energy and emits 12.5 kg of CO₂ — more than 75% of aluminum grades. Typical recycled content is 10%.
Manufacturability7
7040-T7451's machinability is very good (70/100, better than 72% of aluminum grades); weldability poor (20/100); formability poor (25/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Other 7040 tempers and conditions
7040 is also supplied in 6 other conditions. The full side-by-side table is on the 7040 overview.
- T7451DefaultThe standard supply condition for 7040 aerospace thick plate: near-T6 strength with good through-thickness toughness, SCC resistance and low residual stress for deep machining.450 MPa yield · 145 HB
- T6Choose when maximum static strength matters and exfoliation/SCC exposure is low; toughness and stress-corrosion resistance are the lowest of the aged tempers.510 MPa yield · 165 HB
- T651T6 strength with stretch stress relief so heavily machined plate stays dimensionally stable.505 MPa yield · 163 HB
- T7651Choose when high strength plus exfoliation-corrosion resistance is needed in moderately thick plate; toughness a little below T7451.480 MPa yield · 153 HB
- T7351Pick for the most SCC-critical thick sections where toughness beats peak strength.425 MPa yield · 138 HB
- OPick for maximum formability or before re-solution heat treating; strength is far below service level.115 MPa yield · 65 HB
Working with 7040-T7451
Is 7040 easy to machine?
Excellent chip formation in T74/T76 tempers — high-speed carbide, polished flutes, 3–8 % emulsion coolant; stretch-relieved plate keeps distortion low on deep pocket milling.
Can 7040 be welded?
Not suitable for fusion welding (hot cracking, SCC in HAZ); join by riveting, bolting or friction-stir welding with qualified procedures.
Can 7040 be formed, bent or molded?
Form in O or freshly quenched W condition only; aged plate has limited bend ductility and needs generous radii and stress-relief planning.
What surface finishes work on 7040?
Chromic/tartaric-sulfuric anodize plus primer or hard anodize for wear; alkaline etch and conversion coatings work well, avoid strong caustics and dissimilar-metal contact without insulation.
7040 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 | ≤ 0.1 | 0.05 |
| Fe | ≤ 0.13 | 0.07 |
| Cu | 1.5 – 2.3 | 1.9 |
| Mn | ≤ 0.04 | 0.01 |
| Mg | 1.7 – 2.4 | 2 |
| Cr | ≤ 0.04 | 0.01 |
| Zn | 5.7 – 6.7 | 6.2 |
| Zrgrain-structure control (Al3Zr dispersoids) | 0.05 – 0.12 | 0.09 |
| Ti | ≤ 0.06 | 0.02 |
| Others (each)each | ≤ 0.05 | — |
| Others (total)total | ≤ 0.15 | — |
| Al | balance | — |
7040-T7451 — frequently asked
What is 7040-T7451 used for?
7040-T7451 is typically used for wing spars, bulkheads and heavy frames. In short: thick aerospace plate.
What is the yield strength of 7040-T7451?
7040-T7451 has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 505 MPa (73.2 ksi) — stronger than 91% of aluminum grades. Strength varies by condition: see the 7 listed tempers.
Is 7040-T7451 easy to machine?
Yes — machinability is rated very good (70/100, better than 72% of aluminum grades). Excellent chip formation in T74/T76 tempers — high-speed carbide, polished flutes, 3–8 % emulsion coolant; stretch-relieved plate keeps distortion low on deep pocket milling.
Can 7040-T7451 be welded?
Not readily — weldability is rated poor (20/100). Not suitable for fusion welding (hot cracking, SCC in HAZ); join by riveting, bolting or friction-stir welding with qualified procedures.
What surface finishes work on 7040-T7451?
Chromic/tartaric-sulfuric anodize plus primer or hard anodize for wear; alkaline etch and conversion coatings work well, avoid strong caustics and dissimilar-metal contact without insulation.
Can 7040-T7451 be formed, bent or molded?
Form in O or freshly quenched W condition only; aged plate has limited bend ductility and needs generous radii and stress-relief planning.
What is the maximum service temperature of 7040-T7451?
7040-T7451 is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 7040-T7451 and 7040-O?
T7451 is the default condition — the standard supply condition for 7040 aerospace thick plate: near-T6 strength with good through-thickness toughness, SCC resistance and low residual stress for deep machining. O: pick for maximum formability or before re-solution heat treating; strength is far below service level. Yield strength is 450 MPa in T7451 versus 115 MPa in O.
Can FabDigit make parts in 7040-T7451?
Yes — 7040-T7451 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)
- Aerospace thick plate alloys 7040/7050 (T7451, T7651) plate data — Constellium (formerly Pechiney/Alcan) (2020)
- ASM Handbook Vol. 2: Properties and Selection — Nonferrous Alloys — ASM International (1990)
- MMPDS-17 Metallic Materials Properties Development and Standardization — Battelle/FAA (2022)
- EN 485-2 Aluminium and aluminium alloys — Sheet, strip and plate: mechanical properties — CEN (2016)
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.