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Old 02-14-2019, 12:52 PM
crystallographic crystallographic is offline
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Default Welding 7075 - GTAW

This is a nice break-through for tubing parts manufacturers - link below.

While 2024 has been welded since 1943, that I know of, having 7075 enter the weldable realms is very nice.
(Wasn't it Trek bicycles that made some bike frames from welded 2024, some years back?)


https://newatlas.com/welding-aa7075-aluminum-alloy/58449/?utm_medium=email&utm_campaign=2019-02-13 153132 USA Daily Basic 2019-02-13 153957 New welding process opens up uses for formerly un-weldable alloy&utm_content=2019-02-13 153132 USA Daily Basic 2019-02-13 153957 New welding process opens up uses for formerly un-weldable alloy+CID_525f440f5d4a195f3d53729489c20e00&utm_sou rce=Campaign Monitor&utm_term=New welding process opens up uses for formerly un-weldable lightweight alloy

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Old 02-14-2019, 01:20 PM
dwmh dwmh is offline
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Very interesting. There's some smart people about. Thanks for sharing Kent.
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Old 02-14-2019, 06:45 PM
AllyBill AllyBill is offline
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Hate to say this, but I was asked to weld a pair of 7075 skins for a restoration project a few years back and I glued them back together using strips of native material harvested from an unseen joggled edge as filler with no difficulty at all.
It was given a good annealing and furnace cool at the heat-treatment plant to take it to T-0 and beyond first to maximise the available elongation.
I brought it up to temp with a torch before starting as a precaution and gave it a little post-heat too and it welded perfectly. No cracking whatsoever.
Just to be extra sure, I then twice stretched the welds with hammer and dolly then heat-shrunk them back gain to make the weld homogenous with the native material (that works brilliantly) then off it went for heat treatment back to the condition we found it in and has never ailed a thing to this day. I guess if it was a process for new aircraft or nuclear subs it would need a little more consideration but it certainly welds easily enough without cracking if you want it to.

Will

Ooh! And I just noticed that it automatically says MetalShaper of the Month. Cheers for that. Cool.
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Old 02-15-2019, 07:11 AM
Marc Bourget Marc Bourget is offline
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Interesting!


I'd always heard that 7075 welded beautifully but a light "wack" would cause the weld to fail.


You've obviously excelled but did you ever create a coupon to test?


I'm curious what your approach would achieve.


Again Kudo's for your sculpture and welding efforts!
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Old 02-15-2019, 11:25 AM
crystallographic crystallographic is offline
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[QUOTE=AllyBill;153306]Hate to say this, but I was asked to weld a pair of 7075 skins for a restoration project a few years back and I glued them back together using strips of native material harvested from an unseen joggled edge as filler with no difficulty at all.
It was given a good annealing and furnace cool at the heat-treatment plant to take it to T-0 and beyond first to maximise the available elongation.
I brought it up to temp with a torch before starting as a precaution and gave it a little post-heat too and it welded perfectly. No cracking whatsoever.
Just to be extra sure, I then twice stretched the welds with hammer and dolly then heat-shrunk them back gain to make the weld homogenous with the native material (that works brilliantly) then off it went for heat treatment back to the condition we found it in and has never ailed a thing to this day. I guess if it was a process for new aircraft or nuclear subs it would need a little more consideration but it certainly welds easily enough without cracking if you want it to.

Will

Why not share your technique with others, William?
https://awo.aws.org/resource-library...013e-426316799


But then again, you could just go ahead and take it all to your grave ...
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Old 02-15-2019, 07:06 PM
AllyBill AllyBill is offline
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Quote:
Why not share your technique with others, William?

But then again, you could just go ahead and take it all to your grave ...
Hi Kent,

I thought I had. I set out the process but if there's any part of it about which you want to know more please ask. I didn't test the welded material at the time as it was a real struggle to harvest enough material to make the welds in the first place. It was a working restoration so it had to be right but there was nothing left over. I've welded the same material for display only and a much easier process is to dilute down the edges to be welded with 1xxx filler, dress them then dilute back up again with with 5xxx for the final welds, which puts back most of the strength and it won't crack. For extra security stretch the welds then shrink back with heat a couple of times like kneading dough.

Will
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Old 02-16-2019, 08:38 AM
bobadame bobadame is offline
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I tried to weld 7075 once and found it impossible to make it flow together. It seemed to just turn gray and ball up and away from the adjacent piece. The few areas that did flow together cracked immediately. So if I understand this article correctly it might be possible one day to use a filler rod which contains the magic beans which bind the different elements together during cooling. Cool.
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Old 02-16-2019, 11:38 AM
crystallographic crystallographic is offline
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Quote:
Originally Posted by bobadame View Post
I tried to weld 7075 once and found it impossible to make it flow together. It seemed to just turn gray and ball up and away from the adjacent piece. The few areas that did flow together cracked immediately. So if I understand this article correctly it might be possible one day to use a filler rod which contains the magic beans which bind the different elements together during cooling. Cool.

Yes Bob, it's nice when a new filler is developed that takes all of the exhaustive mischief out of the solution.
I remember when cast gray iron got a filler (also containing Ti) that took all of the pre-heat/post-heat/peening joy out of welding it.

"Weld an inch and pound an hour" became a distant memory - after a number of years.

For those doing multiple feet of weld on one casting it was huge progress.

Now the tube-fab guys have a whole new strength level to design with.

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