Distortion when welding 2 small tubes on each end...

[USAeng]

How can you overcome distortion in this situation? The whole thing is becoming somewhat twisted...

There are two tubes about 5/16" dia. about 3' long. they are spaced about 1/4" apart. A solid piece is being welded on each end and then a spacer is tack welded in the middle. The welds are all about 1/8" fillet welds all the way around on each end of the tubes.

See crude picture for a rough visual. Any suggestions? Thank you

 

[metengr]

Can you describe your current fitup/weld sequence?

 

[USAeng]

they have since tried a jig now to hold things down while welding and that seems to have helped...

first he is welding around each tube on the one side then sliding the spacer on and welding and then welding the piece on the other side...

Seems that we can prevent some distortion with the jig and then fix most of the rest by simply bending.

 

[metengr]

Sounds reasonable to me. Thanks

 

[unclesyd]

If you re not already doing this I would make the end spacers in one piece with two parallel holes where the tube slips through and you can weld it on the ends.
I would also look to minimize the welding on the center spacer.

If you have very many of these to fabricate I would look into some type of precision welding such as shown by Weldlogic, Arc-Zone, and many others.

http://www.weldlogic.com/index.html

http://www.arc-zone.com/index.php

 

[Tmoose]

http://www.lincolnelectric.com/knowledge/articles/content/distortion.asp

http://weldingdesign.com/blodgett/wdf_68978/

http://weldingdesign.com/blodgett/wdf_70297/

http://weldingdesign.com/blodgett/wdf_70297/

 

[Guest102023]

Consider brazing instead.

 

[MikeHalloran]

Weld one tube on the inside faces of the end pieces.
Let the other tube be a little longer, so it extends through the end pieces plus a little vigorish, and weld that tube on the outside faces of the end pieces.



Mike Halloran
Pembroke Pines, FL, USA