7075 Aluminum Plate
This aluminum plate is made of one of the strongest of the aluminum alloys. Its use parallels that of 2024, with 7075 selected when higher mechanical properties are desired. 7075 aluminum is an aluminum-zinc alloy with 1%-8% zinc in addition to small amounts of magnesium and small quantities of copper and chromium. This alloy is precipitation hardened to very high strength levels. Alloy 7075 is used in airframe structures and other highly stressed components.
Due to its high strength-to-weight ratio,7075 is used for highly stressed structural parts. Applications include aircraft fittings, gears and shafts, fuse parts, meter shafts and gears, missile parts, regulating valve parts, worm gears, keys, and various other commercial aircraft, aerospace and defense equipment and components.
Machineability and Weldability
7075 in the T6 condition has a machinability rating of 80% when compared to 2011 at 100%. Aluminum 7075 is can be formed in the annealed condition. and can be forged in the temperature range of 700 Degrees to 900 Degrees F. It should be solution heat treated following forging. Aluminum 7075 is a very poor choice for welding. Resistance welding is the only preferred method of joining 7075.
Gas welding should be avoided and the use of arc welding may result in degradation of corrosion resistance.
Heat Treating
7075 may be solution annealed at 900 Degrees F for 2 hours at temperature, followed by a water quench. The alloy may then be given a precipation hardening (aging) heat treatment.
Annealing
Annealing is done at 775 Degrees F, holding for 3 hours at temperature. Controlled cooling at 50F per hour should then be used down to 500F from which it can be air cooled.
Aging
Precipitation strengthening (aging) is done at 250 Degrees F for 24 hours and air cooled for T6. The T73 temper requires heating to 225 Degrees F for 8 hours, followed by 24 hours at 325 Degrees F and then air cool.
| Silicon | 0.4 |
| Iron | 0.5 |
| Copper | 1.2-2.0 |
| Manganese | 0.3 |
| Magnesium | 2.1-2.9 |
| Chromium | 0.18-0.28 |
| Zinc | 5.1-6.1 |
| Titanium | 0.2 |
| Others, each | 0.05 |
| Others, total | 0.15 |
| Balance, Aluminum |
| Thickness | Tensile Strength | Yield Strength | Elongation |
|---|---|---|---|
| In. | KSI | KSI | % |
| .250-4.00 | 83-73 | 73-63 | 13-11 |
