7XXX ¾TªO §Þ³Nªí

7XXX series alloys contain zinc as the main alloying element, usually in combination with magnesium and copper. Alcoa's range of high strength 7XXX alloys are widely used in aerospace structures and are approved by the world's leading airframe builders. For engineering applications these alloys are generally used in the T651 or T652 temper in order to provide maximum strength.

Strength:

These materials offer the highest levels of room temperature strength attainable in rolled aluminium alloys.

Stress relieved:

7XXX plate alloys are stress relieved by controlled stretching, designated T651 or cold compression designated T652. See table overleaf for details.

Machinability:

7XXX are easy to machine, especially in the T651 temper.

Polishability:

7XXX alloys can be polished to a high finish.

Corrosion resistance:

7XXX alloys are susceptible to exfoliation corrosion and stress corrosion cracking in the T651 temper. This can be improved by over ageing. 7XXX alloys often require protection against general corrosion and a wide range of commercial protective coating systems are available.

Welding:

7XXX alloys with more than 0.2% copper are not considered weldable by fusion welding. 7XXX alloys with less than 0.2% can be welded.

7XXX Applications:

7XXX is superseding steels in structural load bearing applications where the benefits of lightness, specific stiffness and high strength-toweight ratio can be exploited.

• Machined components

• Load bearing structures, e.g. cargo
  containers

7XXX alloys, with excellent machinability and wear resistance are widely used for mould applications.

7xxx series alloys technical data

STANDARD DIMENSIONAL AVAILABILITY

Alcoa Europe only supplies plate that exceeds the requirements issued by the major specifying authorities e.g. European Standards. 1. These dimensions show only the range of capabilities and cannot necessarily be provided in every combination of these sizes. Other sizes may be available, subject to enquiry. 2. The above alloys are only available in Mill Finish 3. * denotes maximum width decreases with increasing thickness 4. ** denotes wider widths may be available on request

TYPICAL PHYSICAL PROPERTIES