Straightening a weldment

[jwmelvin]

I’m building some material racks out of 2x1/8 angle. As expected, they have quite a bow from welding:


As I understand it, heat straightening would be the best approach? I don’t have a torch but in theory could get a oxy-propane setup.

Is it worth trying to straighten these using a 20T press? It seems like it might work.

If you were heat straightening, would you heat the areas I highlighted in yellow? Or those in pink? Or somewhere else?


And am I correct that the process is to heat to orange hot then cool with sprayed water?

Thanks for any advice,
Jason

[Mac's Crew]

If you spray it with wat6it will crystallize the structure of the steel making it harder yet weaker. As hard breaks soft wears.

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[thegary]

If you spray it with wat6it will crystallize the structure of the steel making it harder yet weaker. As hard breaks soft wears.

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Heat the area you have marked in pink. Then use a cold wed rag to quench the area. Watch the piece as it straightens and stop quenching when it is straight. It will take a couple of times to get the process down but after that it will go fast. Experiment with the amount you heat it too.

The heated area will expand when it is hot and will make the bend worse while it is hot but the quenching will shrink the steel back down and straighten the piece.

[SlowBlues]

If you don't have a torch or press, just match every weld (with another weld) on the opposite side of the bowed angle iron (to balance the shrink forces) and then grind them down (or don't).

Match every weld and then you can go back and add more weld (shrink) if needed. Easy, and time consuming, but a torch setup is ~$300, a hydraulic press is ~$150 and takes up quite a bit of room.

Since your racks look straight in one dimension i would heat in the purple areas, but only on the bowed side (not the triangular bit on the "top" side in the pic). If it is bowed in both dimensions then heat both sides to straighten in two directions (up and to the right in orientation to the colored "where to heat" pic).

[Lis2323]

And be patient. It might get worse before it gets better. And when things start going the way you want, DON’T get greedy. Take slow steps and try to remember what works and what doesn’t.

You’ll get it. Have fun!

[BD1]

What is this getting mounted too. ??


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[tapwelder]

In this case I would Bend it cold. Concentrate the bending force on the flange. Angle likes to twist. You could also weld a bead opposite the welds.

However, you do it, patience is important. With heat /water or welding, stop and wait until the bending action stops. The contraction is creating the results and it is always greater than the expansion.

[12V71]

And be patient. It might get worse before it gets better. And when things start going the way you want, DON’T get greedy. Take slow steps and try to remember what works and what doesn’t.

You’ll get it. Have fun!

This, exactly. Shrinking is hard to undo. And it will happen faster than you think.

[ronsii]

This, exactly. Shrinking is hard to undo. And it will happen faster than you think.

LOL!!! Ain't that the truth

[cwby]

To straighten it cold, you can set it on top of a hydraulic jack on your table. Center of bend. Chain each end to the table, jack it past true & let pressure off to check it. It may have to go an inch or two past true to make it relax back straight.

[12V71]

LOL!!! Ain't that the truth

On a serious note I do quite a bit of flame straightening. Here's a pic of some from last year. This was the startpoint.
The second pic is almost there, still needed some re-arching when I was done with getting it straight enough to track down the road.

[Welder Dave]

Do you have some strong Bessey clamps or C clamps? Maybe you could put them back to back with 2x4's or 4x4's in the middle and use clamps at the ends to try and straighten them out some. Will have to go a little more than required. This would be relatively inexpensive to try. If the racks are bolting on a wall will probably straighten out when bolting on.

[OPUS FERRO]

12V71

Here's a pic of some from last year.

Any idea of what caused the deformation . . . ?


Opus

[12V71]

12V71



Any idea of what caused the deformation . . . ?


Opus

It had something heavy dropped on the right hand side (as sitting in the drivers seat) there were a couple of buckled spots in the top flange that were trimmed out and replaced after things were straightened out. The current owner bought it like that and ran it several years that way. I only suggested straightening it when I had to re deck the thing.

[jwmelvin]

What is this getting mounted to?

To a 2x6 wall, with tabs that I will weld on to each bracket.

In this case I would Bend it cold. Concentrate the bending force on the flange. Angle likes to twist. You could also weld a bead opposite the welds.

To straighten it cold, you can set it on top of a hydraulic jack on your table. Center of bend. Chain each end to the table, jack it past true & let pressure off to check it. It may have to go an inch or two past true to make it relax back straight.

Do you have some strong Bessey clamps or C clamps? Maybe you could put them back to back with 2x4's or 4x4's in the middle and use clamps at the ends to try and straighten them out some. Will have to go a little more than required. This would be relatively inexpensive to try. If the racks are bolting on a wall will probably straighten out when bolting on.

Thanks I have a press it’s just an awkward shape to fit in there. These are some helpful ideas on how to get around that. I appreciate the help.

If you don't have a torch or press, just match every weld (with another weld) on the opposite side of the bowed angle iron (to balance the shrink forces) and then grind them down (or don't).

I thought about this too, thanks. I’ll try some mechanical methods first and then maybe some additional beads.

And be patient. It might get worse before it gets better. And when things start going the way you want, DON’T get greedy. Take slow steps and try to remember what works and what doesn’t.

You’ll get it. Have fun!

I appreciate the encouragement and useful guidance. I knew before I f’ed it up I should ask people who have done it. I was kind of hoping the only solution was to buy a torch and oxygen tank (it would be about time) but I’ll give the mechanical methods a go first. Thanks all. I’ll report back.

[jwmelvin]

I first tried some clamps on my table but it seemed pretty hard to move the metal:


So I built a frame to support my weldment at two points and hold it from twisting:


I overdid it a bit on the first two but the third came out pretty straight:

[Welder Dave]

Glad it worked. How many pounds are your clamps rated for?

[JayWal]

That's pretty impressive, it can be pretty tough to get a warped angle that straight. Looks great

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[BD1]

Glad you got it straightened out.
You do know what caused that right ?
So it will be avoided on future projects .


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[MetalMan23]

If you don't have a torch or press, just match every weld (with another weld) on the opposite side of the bowed angle iron (to balance the shrink forces) and then grind them down (or don't).

Match every weld and then you can go back and add more weld (shrink) if needed. Easy, and time consuming, but a torch setup is ~$300, a hydraulic press is ~$150 and takes up quite a bit of room.

Since your racks look straight in one dimension i would heat in the purple areas, but only on the bowed side (not the triangular bit on the "top" side in the pic). If it is bowed in both dimensions then heat both sides to straighten in two directions (up and to the right in orientation to the colored "where to heat" pic).

I was about to say this, but you beat me to it, this is the way to do it.
I did some stainless steel fabrication with 2x2 tubing, the way it was laid out made it warp, I had to weld on the opposite side to straighten it out, it works fast too,

[jwmelvin]

Glad it worked. How many pounds are your clamps rated for?

The big one is 2000 lb according to Kant Twist. It felt like I was going to have an easier time with the press so I went with that.

Glad you got it straightened out.
You do know what caused that right ?
So it will be avoided on future projects.

Well, I thought it was inherent to welding on one side of the long piece. I’d love to hear more about how to avoid it.

[Lis2323]

Clamping it down securely and taking your time with the welds allowing them to cool will help. Skip around also. Do one leg near an end and then perhaps one halfway up the length. Don’t do them consecutively.

[Welder Dave]

Being it's only 1/8" it will warp much easier with enough weld for 1/2" thick material. I think your racks could be bent into pretzel shapes before they broke. Clamping them back to back when welding them would help and like said above don't weld one section all at once.

[Kelvin]

Clamping it down securely and taking your time with the welds allowing them to cool will help. Skip around also. Do one leg near an end and then perhaps one halfway up the length. Don’t do them consecutively.

Also, welding hotter so you can get in and get out faster (with less total heat input) can help, too.

[Lis2323]

I have often wondered for welding smaller heat critical projects if something like this would work to minimize distortion.




Obviously if it worked it may not be cost effective on bigger jobs but has anyone ever tried something similar?