Aluminum 2018

Aging Procedure

Age hardening is accomplished starting with the alloy in the solution treated, T4, condition (950 F and water quenched). Age at 340 F for 10 hours followed by air cool for T61 temper . Age at 450 F for 6 hours and air cool for T71 temper.

Annealing Procedure

Annealing ("O" temper) is done at 775 F for 3 hours and then controlled cooling at 50 F per hour down to 500 F, followed by air cooling.

Applications

Commonly used in the manufacture of aircraft engine cylinders and in heads and pistons.

Cold Workability

This alloy is primarily intended for fabrication by forging and/or hot working. However it may be cold worked by conventional means but this should be done with the alloy in the annealed condition.

Forgeability

Forging should be done in the temperature range of 900 to 970 F, finishing at 500 F before reheating to 970 F if necessary.

Formability

This is primarily a forging, or hot working, alloy. However cold working can be done with the alloy on the annealed condition.

Hardening Procedure

Hardens by heat treatment and aging and/or cold working.

Heat Treatability

Solution heat treatment is done at 950 F for sufficient time to allow uniform heating throughout, then water quench. For heavy section size parts the water quench should be done using water at approximately 200 F.

Hot Workability

The alloy may be hot worked readily in the temperature range of 500 to 970 F.

Machinability

The alloy is readily machined, especially in the aged condition for smooth finishing. In the T4 condition (solution heat treated) the alloy is softer and may tend to build up during lathe turning or milling. Use of lubricating oils is recommended.

Other Mechanical Properties

Shear strength T61 temper 39 ksi.

Other Physical Properties

Electrical conductivity 40% of copper.

Principle Design Features

This is a high strength, age hardening, forging alloy.

Tempering Procedure

Not applicable.

Weldability

Welding of this alloy by conventional methods is NOT recommended. It may be arc or resistance welded by special techniques