ALUMINUM 7075 FORGING PARTS
PRINCIPAL DESIGN FEATURES
The 7075 alloy is capable of high strength as developed by heat treating. It also has excellent properties at low temperatures.
APPLICATIONS
Commonly used in the manufacture of aircraft and other aerospace applications not requiring the corrosion resistance of Clad 7075.
MACHINABILITY
It is best to machine this alloy in the annealed condition. Machining capability is good and oil lubricants should be used.
FORMING
This alloy is comparatively strong for an aluminum alloy. As such it prodsuces greater springback during forming operations. Forming is best done in the annealed condition and if difficulty is encountered then warming the material to 200 – 250 F will assist formability.
WELDING
Resistance welding is the only preferred method of joining AL 7075 alloy. Gas welding should be avoided and use of arc welding may result in degradation of corrosion resistance.
HEAT TREATMENT
This alloy may be solution annealed at 900 F for 2 hours at temperature, followed by a water quench. The alloy may then be given a precipitation hardening (aging) heat treatment — see “Aging”.
FORGING
The alloy may be forged in the temperature range of 900 F to 700 F. It should be solution heat treated following forging.
HOT WORKING
Warming the material to 250 F will greatly assist formability.
COLD WORKING
Cold working is readily accomplished with the alloy in the soft, annealed, condition. Conventional forming methods may be used, but springback is greater for this alloy than for other of the aluminum alloys.
ANNEALING
The temperature for annealing AL 7075 alloy is 775 F, holding at temperature for 3 hours. Controlled cooling at 50 F per hour should then be used down to 500 F from which it can then be air cooled.
AGING
Precipitation strengthening (aging) is done at 250 F for 24 hours and air cooled for T 6. The T 73 temper requires heating to 225 F for 8 hours followed by 24 hours at 325 F and air cooling.
OTHER PHYSICAL PROPERTIES
Electrical conductivity 36% of copper.