Difference to be considered while designing Forming block for 2024-T3 3

[Gopalakrishnan C]

Hi,
We have form blocks for 2024-0 condition material, now i need to design form block for 2024-t3 063"thk material. Please help me on points to be considered.Thanks!

 

[rb1957]

wait for Will to respond, but my 2c is make the form block to suit the final shape. When you HT to T42 the piece may warp but locally forming (= careful hammering) will be a conforming part.

You must be bending a tight radius ? Maybe a bigger problem is the resulting thickness (around the bend) ??

another day in paradise, or is paradise one day closer ?

 

[Gopalakrishnan C]

Thanks rb1957, The material go only with T3 condition not going for T42. the bend radius is .33" i just need a joggle over the 20" sheet.
i am wondering if i need to consider spring back on this part or no? Thanks

 

[rb1957]

sorry but you cannot (AFAIK) heat treat from O to T3, only to T42 (which is effectively the same temper).

"the bend radius is .33" i just need a joggle over the 20" sheet." … I'm surprised this needs to be done in O condition ?

 

[Gopalakrishnan C]

Sorry about that. I was not clear. I am going to form 2024-T3 condition material. The sheet thickness is .063" and bend radius of .33"

 

[rb1957]

oh, I'm sorry, I misread your post. I think there's no problem forming T3 to the shape you're saying (BR = 0.33", t = 0.063") with a form block intended for O condition.

another day in paradise, or is paradise one day closer ?

 

[berkshire]

If you are putting a joggle in over 20", are you pressing this in with a press, or hammering it in with mallets? As a general rule forming t3 material will encounter spring back in the material so you will need to overbend slightly to achieve the final desired results. This job can also be done with a joggling roller. This can also be done in two operations on a hand brake.
B.E.

You are judged not by what you know, but by what you can do.

 

[WKTaylor]

G... As You suspected... AND this is highly non-standard.

The form block for rubber-press hydroforming in sheet-metal 2024-T3 temper will have to include significant allowance for 'spring-back'**... which means a 90-Deg finished bend-angle will need to be bent to a substantially higher angle... unlike forming in the 'w' temper. Incorporating one-or-more joggles, at the same time, might not be feasible or practical on one form-block. [**I don't have spring-back tables handy, this PM]

The only-way I see this 'working' is a different approach... finger-break-form the part axially... then joggle-form transverse, afterwards... but even this seems overly complex/sketchy.

I am deeply curious as to 'why' You aren't forming in the O-> SHT-> W-> form-> age-to -T42 sequence?

NOTE.
A 'few tricks-of-the-trade' about heavy forming or stretch-forming in -T3 temper...

Ensure sheet metal is clean and free of surface scratches/gouges/etc

Deburr/radius all edges to prevent forming cracks.

Use aqueous forming lubricant [soap?] to minimize drag.

Immediately after forming, age HT to -T62 [I don't think -T81 applies after heavy forming] for stress relief and 'stability'.

Possibility of the appearance of 'Ludder's lines' is very real and may/may-not present a problem.






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]