Full Transcript:

What’s up guys? This is Michael with Michael Talks Metal back for another talk on Aluminum. How about a quick tap of the subscribe button, or if you are enjoying the video, a little like? Thank you and let’s jump in! Today our video is about two of the highest strength of  the aluminum alloys.

Both are in the 7xxx series….. 7050 and 7075 to be precise. Both are widely used in the aerospace industry.

If you have not seen our video on aluminum tempers or if you would like to review click here

Primary alloying element in this series is Zinc.

The Aluminum Association, the American industry organization that has established standards also uses a comparative rating system for various properties  of aluminum alloys.  An A rating is the most favorable and E is the least.  Again these are comparisons within aluminum alloys. An alloy and temper rated “A” is superior to one rated “B” and so on.

Aluminum chemistry requirements routinely contain a restriction of point 05% maximum each for any unspecified elements and a total of point 15% maximum which applies to all these alloys. Balance element is aluminum.

7050 UNS A97050  has a chemical composition of point 12 % maximum silicon,

point 15 % maximum iron, 2 point 0 to 2 point 60 % copper, point 10 % maximum Manganese, 1 point 9 to 2 point 6 % magnesium, point 04 % maximum chromium, 5 point 70 to 6 point 70 % zinc, point 06 % maximum titanium , and point 06 to point 15 % zirconium.

The T76 and T74 tempers (and variants likeT7651)  are rated C for general corrosion, B for stress corrosion,  B for machinability,  B for anodize response and a D for weldability.  Major application is for aircraft structural parts.

7075  UNS A97075  has a chemical composition consisting of point 40 % maximum silicon, point 50 % maximum iron, 1 point 20 to 2 point 00 % copper, point 30 maximum manganese, 2 point 10 to 2 point 90 % magnesium, point 18 to point 25 % chromium, 5 point 10 to 6 point 10 % zinc, and point 20% maximum titanium.

The  T6 tempers and variants like T651 are rated C for stress corrosion but are the highest strength.

The T73 tempers are a bit lower in strength but earn a B rating for stress corrosion resistance.

Both the T6 s  and T7 s are rated C for general corrosion, C for machinability, B for anodize response,  and D for weldability

Perhaps the most widely used high strength alloy in aerospace applications.

The high strength T6 tempers  of these alloys should be used with caution when used in environments where stress corrosion can be an issue  They should be protected from exposure (eliminating the contact with the environment) or other tempers or other alloys should be used…more on this topic in our next video.

Commercial applications generally specify ASTM standards. Aerospace applications utilize AMS standards or the defense and federal standards.

As always, there are detailed requirements within  the full temper designation and any specifications that can require specific products and processing so we caution you to carefully check the specs.

Thanks for watching and if you made it this far, please consider hitting that little subscribe button or if you have missed any of the previous videos, click here! Thanks again for tuning in, see you next Thursday for another round of Michael Talks Metal. Have a great week, this is Michael, and I’m out!