4" sqaure aluminum tubing

[weldjunky]

i had to weld 2 6"x14" peices of aluminum plate on the tubing and now the tubing has a slite bananna bend to it how should i go about getting this out so its straight ? it is '20ft long and is going to be a trial for concrete

 

[DAVIDSTECKER]

You could make a "straitening press" using a hydraulic jack if you have a way to counter act the force by securing the other section of the tubing. Use a tight string to find where the bend is and where it is straight.
I would think that the bend is very localized so you would only need to concentrate on the area near the welds.
Depending on the material, if you someone with a lot of structural weld experience there is a method heating the area and then selectively cooling one side to get the material to pull back in line.
If you have to do this again you can pre-bend the tubing the opposite way and then the welding will pull the tube straight. Again this takes experience on the part of the welder and/or shop.
Another method I have read about but do not have any hands on experience with is a vibratory system that is applied during the welding to relieve stresses before they pull the tubing.

 

[mfgenggear]

did you preheat the aluminum before welding

 

[mfgenggear]

an other sugestion if you have access to a press.

mount/support the tubing assembly on each end with steel supports(steady rest or horses). heat the assembly, then press in the center of the bowed section with a press.
use a dial indicators with plenty of travel to verify
the amount of travel or verify with a straight edge.