We have parts cast from 356 aluminum alloy and heat treated at the
foundry. We machine them after heat treating. Never thought of doing
it any other way. The heat treatment can induce some distortion some
times (not often) so that would be bad if one was going to anneal,
machine and then heat treat.

Pete Stanaitis
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Karl Townsend wrote:
I'm preparing to machine several AL 7075 T6 forgings...

"The Kid" (my son) tells me I should anneal before machining because
there will be hard brittle spots. Easy enough to do at the anneal temp
of 775 (not sure how long). But, then I haven't got T6 grade 7075 AL
anymore. How would I get it back to T6 grade?

Or, am I better off with plan "A"? Don't anneal.

Karl