Round number for heat treatment?

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pfarber

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Before I call up the company's I have found I wanted to get a general idea of what the cost of heat treating a -O aluminum alloy to the -T3 state.

Anyone have any small projects done (ie wing ribs)? I know I can form the 2024-T3 around a form, but I think It will be much easier if I did all the forming to -O 2024 the get the lot heat treated... unless the cost is just unrealistic.

Anyone do it and have a recent price/quote?
 

Dana

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I bent 3/4" 2024-T3 tubing into a 52" diameter ring around a wood form for a paramotor cage, no problem. Had to bend it to about half the final radius to allow for springback.
 

Angusnofangus

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Before I call up the company's I have found I wanted to get a general idea of what the cost of heat treating a -O aluminum alloy to the -T3 state.

Anyone have any small projects done (ie wing ribs)? I know I can form the 2024-T3 around a form, but I think It will be much easier if I did all the forming to -O 2024 the get the lot heat treated... unless the cost is just unrealistic.

Anyone do it and have a recent price/quote?
I used to drop off parts to be heat-treated at a local shop, but never saw the bills, but would be interested to know what kind of quotes you get. A larger shop should be able to do all your ribs in one or two cooks. I would be surprised if it would be less than $500.
 

Aviacs

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Testing is actually pretty easy, one way is with a Rockwell tester, which checks the hardness of the aluminum. Five minutes per part, max. You just need the tester, which I'm sure isn't cheap.
Well yes, and "maybe"

My note about interesting discussion was my link to the heat treat discussion on Eng-Tips.com; and the described process for T3/T42

Have you read the process for T3, which is not really a post forming option? (T42 is, though that is "equivalent to T3")
Brinnell tester is more appropriate to published specs, but Rockwell can be used & converted.
Have you ever used a Rockwell tester & interpreted the indentation? (I briefly owned one, used it for steel tooling inspection)
Do you have the calibrated sample blocks for the hardness T3 condition represents?
I suspect from the specs, you would have quite a fine range of Ra or Rb values that might or might not be acceptable.
Those hardness values interpolated, they might or might not fully represent all the attributes of the T3 or T42 condition.

"Hardness" of a material is a simplified proxy for other values like tensile strength. Yet properties like elongation at yield matter in the spec, as do other physical properties of the material (for steel tools, given a base hardness, i'm much more interested in Charpy values relating to toughness, e.g.) In some materials like PH stainless steels, and in aluminum, there are steps in which a very small temperature and soak range makes large material changes. In fabricated parts, there is also the issue of uniform response to treatment.

Rockwell dents are a good quick way to feel good about a material, if you don't have to think about the application too much.

BTW, I'm not saying T42 would necessarily be difficult, given a good (uniform, stabile control) furnace. I'm pointing out that facile notions of Rockwell testing could be due a bit more consideration.

AFA the OP, i was merely pointing out that "T3" is not really an option, ex-factory that manufactured the sheets. T42 is, and might be worth reading up when the spec/rfq is posed to the heat treater. Or whether another T condition in the range might be.

smt
 

Angusnofangus

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Well yes, and "maybe"

Have you read the process for T3, which is not really a post forming option? (T42 is, though that is "equivalent to T3")

T3 and T42 are not just equivalent, they are the same temper. It was just arrived at slightly differently. Aluminum Alloy Heat Treatment Temper Designations

Brinnell tester is more appropriate to published specs, but Rockwell can be used & converted.

Rockwell is used by the OEM that I used to work for, and they deemed it appropriate and so does Transport Canada. So is Brinnell 'more appropriate? I don't think so.


Have you ever used a Rockwell tester & interpreted the indentation? (I briefly owned one, used it for steel tooling inspection)

Yes. I have used a Rockwell tester, also the sample blocks.

Do you have the calibrated sample blocks for the hardness T3 condition represents?
I suspect from the specs, you would have quite a fine range of Ra or Rb values that might or might not be acceptable.
Those hardness values interpolated, they might or might not fully represent all the attributes of the T3 or T42 condition.

Not sure why you would think that Rockwell findings would be somehow dodgy.

Rockwell dents are a good quick way to feel good about a material, if you don't have to think about the application too much.
BTW, I'm not saying T42 would necessarily be difficult, given a good (uniform, stabile control) furnace. I'm pointing out that facile notions of Rockwell testing could be due a bit more consideration.

I have no idea of the point you are trying to make here.

Rockwell is an accepted way of certifying the post-heat-treat conditions of parts, Brinnell is an alternate way, accurate I assume, but I've never used it.

AFA the OP, i was merely pointing out that "T3" is not really an option, ex-factory that manufactured the sheets. T42 is, and might be worth reading up when the spec/rfq is posed to the heat treater. Or whether another T condition in the range might be.

The OP was asking about forming ribs with 2024 in the T3 condition v forming them in O and heat treating. By making them in O and then heat treating they become T4. Unless you are into some exotic stuff, that is the usual post heat treat temper range for 2024. Don't know what you mean by 'another T condition in the range might be'. T refers to the method of obtaining temper. There is a hardness range for each alloy that is typical for that temper.
smt
 

pfarber

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Amazing, this took less than a day to not only not answer the original question, but shot off on a wild tangent not related to the original question.

I would pay good money to join a forum where the OP can delete the unresponsive posts people 'contribute'
 

BBerson

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I guess you missed this detail in the link above that explains why shops don't do this much for individual customers.
"NOTES.
Aerospace heat treaters prefer HT/quench of raw [semi-trimmed blank] stock... then forming while in the unstable 'W' temper... then natural aging to -T42 . Lots of good reasons for setting up fab sequence this way."
 
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pfarber

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I guess you missed this detail in the link above that explains why shops don't do this much for individual customers.
"NOTES.
Aerospace heat treaters prefer HT/quench of raw [semi-trimmed blank] stock... then forming while in the unstable 'W' temper... then natural aging to -T42 . Lots of good reasons for setting up fab sequence this way."
I am not concerend about the process. That's step II after I determine if its financially feasible to even consider it.

Since you seem to want to 'contribute'... what did you pay, how large was the order (in lbs)?
 

proppastie

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but I think It will be much easier
probably most here saw this part of the quote and reacted to it......only thing I remember was L Pazmany saying something to the effect of "Pretzel" (warpage)

there probably is a good reason why no one here will be able to give you a price they paid for this service.
 

User27

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Start with blanks cut from T3 or T4, solution heat to soften and bend, which will also remove any warpage.
Age back to T4.
The quenching after cooking will often cause warping so carry out the forming operations after heat treatment.
No idea of the cost for small batches.
 

proppastie

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so carry out the forming operations after heat treatment
we learn even if we do not answer what OP wants to know...this is the way this site works......

warps after solution heat soften? and forming will remove the warpage ? and it will not warp again when it age hardens?......

so Pazmany's ribs must had done it wrong. ( seem to remember him saying the ribs came back like pretzels so perhaps he sent formed condition O ribs to the heat treat shop )
......so starting with O material is the wrong way to go?
 
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BBerson

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Pazmany started with condition O but was ready to straighten the parts within minutes after quench.
The parts remain soft for several minutes or more if packed in dry ice.
He lived in Los Angeles near the industry in 1970. No other plans seller prescribes heat treatment, as far as I know. They all use 6061-T6 or T4 as supplied and use fluting instead of heat treating.
 

Angusnofangus

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we learn even if we do not answer what OP wants to know...this is the way this site works......

warps after solution heat soften? and forming will remove the warpage ? and it will not warp again when it age hardens?......

so Pazmany's ribs must had done it wrong. ( seem to remember him saying the ribs came back like pretzels so perhaps he sent formed condition O ribs to the heat treat shop )
......so starting with O material is the wrong way to go?
Ribs , or any other part, that is made of 2024-O, when heat treated will be immediately quenched when coming out of the oven. This is what causes them to resemble pretzels. It is then aged for 96 hours during which it reaches temper. After quenching it is still soft, it is W condition, and can easily be straightened. Material that was originally 2024-T3 brought to W by heat treating and then formed just needs to rest for the 96 hours in order to return to its tempered state.
 

TFF

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Sounds like unless one is local, or the heat treater will take on the straightening, which means some sort of go / no go gauge and tooling and instructions along with more cost, it would be best to design without needing to need the service.
 

Mad MAC

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There are 3 other options
6013-T4 formedinT4 and then HT to T6 (heat treatment is a bake like 6061-T4 so little distortion, sits between 2024-T3 and 6061-T6 strength wise)
2024-T4 Kaiser T-FORM (never seen it or used it) requiring no HT will no doubt be priced into sheet cost.

Otherwise there is warm forming of 2024-T3 which just makes 2024-T3 a little bit more formible (at our end of the market its probably a tub of boiling water to heat the blank to 100 deg C before forming). Anyone tried it?
 
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cvairwerks

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Most SRM’s for military a/c from about 1954 or earlier give the process times, temps and other info for both solution and air tempering 2024O to the ST condition. It’s not hard with a little bit of equipment, some calibrated temp measuring capability and the desire to do it. The better option is find a treater that is local, knows how to do it to aerospace specs and get with them. Most will quench, do an inspection and pack on dry ice. At that point you’ve got a bit under 96 hours before the parts reach full hardness to do any rework needed.
 
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