Quote:
Originally Posted by fciron
Kent, are you saying that 6061 can be annealed but it will age harden again in 12 to 18 hours?
Just want to be sure I understand you correctly.
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"Annealing" is a procedure done to soften metals with correct heating to correct temperatures, holding for a correct amount of time, and quenching at a given rate.
Different metal alloys require different annealing procedures, correctly done.
For
full anneal,
heat-treatable aluminum alloys must be taken to 925F, held to soak completely and then the temp. is lowered 50deg F per hour until 350F is reached, and then the part may be cooled in any fashion. This is how to get a full anneal on alloy 6061, as well as 2024, 2019, 2117, 7075, 6063, 6153, and etc.
Annealing this family of aluminum alloys requires a controlled environment.
"In the field", outside of the controlled environments, the craftsman can only do a "partial,
temporary anneal" - which is to take his part to 650F and then quench. And, yes,
precipitation hardening takes over and brings the part roughly back to "hard" in 24-36 hours.