Terry wrote:

Do you think that even if I sucesfully weld the flanges on the tube
without warpage (while mounted to some sort of support piece), that
when I remove the support piece from the flange, it will have some sort
of memory and warp anyway?

It will.


It would probably be best to let the piece
completely cool down before I pull anything apart.

Doesn't help that much.

I would (if you insist on machining then welding) weld it in a different
way that makes less warpage.

Drill holes into the flanges (diameter 6..7mm) and countersink them (on
the outer side). The holes have to match the center of the tube's wall.
Weld into those holes with a MAG (quite high current). These welds tend
to pull the flange flush to the tube. Of course you have to clamp your
work while welding.
Trick is to make the welds in a short time with high current that
assures that you melt the tube. You won't have succes with stick welding
and less success with TIGing.
Make some trial welds to get the trick. It is not very difficult.
There are even special gas nozzles (for MIG/MAG) for that job, but you
don't need them. I have one but never use it.
Holes can even be bigger -to some amount- than the tube's wall thickness

Nick
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