"Richard Hanley" wrote in message
...
I have a part to make that calls for 6061 T6. I have some 6061 T651.
Can anyone tell me the difference between them?
Thank You Richard

T6 is precipitation hardened; T651 is precipitation hardened and then
stretched or rolled. T651 has greater long-term stability, which makes it
more suitable for use in instruments and other applications that would
suffer from dimensional change over periods on the order of a year or so.

Machinability and other properties are considered to be the same for both,
or quite close.

This is from the ASM's _Metals Handbook_, 9th Edition.

--
Ed Huntress
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