You only have to anneal it if you have to anneal it. What do you have in mind?

The quick and dirty is to wave an acetylene torch across it with the oxygen off to coat it in soot. Then, set the torch neutral and heat until the spot burns off.

btoyarzo...

Quote: I have some 'large rings of aluminum'...

Are they in-fact 6061-T6??? Were they forged or flash welded... or...???

What material specification(s) is(are) the rings? Were they delivered by a vendor or did You make them??

WHAT 'NEED" is forcing You to anneal them... if they are already in a full HT state.

How LARGE is LARGE??

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

Hi All, I appreciate the help. Theses rings are in fact 6061 T6 material and weigh about 40 lbs. a piece. Currently the old way to do it was 375 F for 3 hours to soften the material. Then after 3 hours we open the oven door and allow to air cool. They were delivered by a vendor and are about 15" OD by 13" ID and 4" height. They were machined from billet as well. I am not sure why they want them annealed. I believe you are correct that they are fully heat treated already. I'm not a Metallurgical Engineer but a Manufacturing Engineer. If you could possibly direct me to a Text which could help me I would appreciate that, many thanks!

Why buy 6061-T6 if annealing is required? Why not purchase 6061 and then heat treat after forming to produce desired strength?

Per AMS2770 and AMS-H-6088 [was MIL-H-6088]... the heat-treat operation You described... "...Currently the old way to do it was 375 F for 3 hours to soften the material. Then after 3 hours we open the oven door and allow to air cool...." is shear nonsense.

HT @375F is roughly in the AGE HT range... partial and full annealing are done at much higher temperatures... and never to fully heat-treated parts without deliberate consideration as to restoring the nominal 'working' HT. Typically this might be used by an OEM or second tier processor... rarely-if-ever by a end-user.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

I am here to get through the methods I have been assigned to figure out, with all your help and insight, a way through this mess. This issue to me is not "shear nonsense". So please give advice without being critical and I am very thankful!

So I see we are doing this process incorrectly. What is AGE HT? I am unfamiliar with this acronym and am not a Metallurgical Type Engineer. We are an OEM by the way. I have programmable Grieve and Blue M ovens.

Again, I am thankful for guidance and your assistance. So how what advice would you give to HT these materials?

btoyarzo... since You 'bristled' at the term 'nonsense'... then I will substitute the term 'pointless, as far as I can see'.

You need to discuss this in-depth with Your company's materials/process engineer [or scientist or lab-tech]. IF You are heat treating [any alloys] on a regular basis, these 'specialists' are a necessary part of the process.

AND It is important to refer to your established HT process specification [what ever it is] for aluminum alloys. A non-aerospace HT specification... or a non-US HT specification... may explain Why Your company is doing it's doing.

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

Hi WK: Wow! Just skip my question next time and take your bad attitude elsewhere. I was looking for advice not a lecture. I see you are a Legend in your own mind.

I presupposed this forum had "Professionals" that helped and advised people who are seeking advice, but I see you are not capable of being Professional in any sense.

btoyarzo...

I humbly suggest You 'click on the tab' with [YOUR name] highlighted... and then 'click on the tab' with my name [WKTaylor] highlighted...

SWAG [on my part]: You are in your 20s or early 30s [YO] working for a small non-US company.

PS: I am NOW 'the old-gray-haired guy' I used to call-on for advice and wisdom of experience.

I won't red-flag Your post, yet... someone-else might be able to provide You answers without needing more details.

Some wisdom from those 'much wiser than me'...

"You deserve to get what you ask for: but if You don’t ask for very much, don’t expect to get very much.”-- R** N*****, ****** Engineer [summarizing his experiences with critical aircraft fastener manufacturing].

Alternate versions, by other engineers…

"You don't get what you want... You get what you ask for. Ask carefully!” –TheTick, Eng-Tips

"You may not get what you asked for... but [for sure!] you never get more than you ask for!” –EdStainless, Eng-Tips

and, just because...

"Underestimate me... This’ll be fun." --SheShirt Logo

NOW, I'll 'go-dark-to-you and ghost-away', as You recommend...

Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

The preamble: Al alloys such as 6061 are tempered by first by heating to put all of the alloying elements, (Mn, Si, etc.) into solid solution, then quenching to approx. room temp. The alloy elements won’t do anything on their own for a few millennia or more; however if heat is applied, the elements will ‘precipitate’ into submicroscopic clumps that strengthen. So depending on the Time-Temp recipe you’ll get the various tempers designated as -T4, -T6, T7, etc. each having ad/disvantages. T6 is about optimum for strength. 375F for a couple hours could be ‘overaging’ like maybe into T7. You are doing something, so the descriptor of 'nonsense’ for this operation may not be totally accurate. (BTW T7 will be less strong, more ductile, I think, and better for corrosion resistance.)

Finally to answer your question - I think you should start at the beginning and get those elements all into solution, then quench or air cool the part. I may be wrong but that should be -T0. For sure, get a copy of the ASM Heat Treater’s Guide. The C2H2 treatment won't work - the part is too thick. Lastly for machinability, T6 should have very good chip formation, so reconsider annealing.

Hi Jughandle: Thank you for your input. I will get a copy of the ASM Heat Treaters Guide. These parts are going into an extreme corrosive environment and are way over designed as far as mechanical strength goes. I am just picking up a process where the old ones at my company have used this "Tribal Knowledge" when making these parts. This fact was overlooked by the previous poster who seemed more concerned with their own vast accomplishments rather that helping a fellow engineer with a problem out of his scope of of knowledge. But I did need to know if this was in fact "nonsense" but a more tactful way of explaining why would have helped me more. Thank you!