[cjarnutowski]

Hi guys, thanks for having me.

I tried to search for this but its pretty difficult to form a query for this specific question.

I am welding a 3"x.25" round tube to a 24"x24"x.25" plate, dead center. The material is steel and the process is TIG. I was hoping to hear some of your tricks for preventing the plate from "cupping" up toward the post on the side of the weld.

Any wisdom is appreciated,

Thanks,
Chris

[exnailpounder]

Welcome to the forum! Plate is the worst offender for distortion. I have had some success with tacking a couple pieces of angle on the non-weld side, clamping the piece down, doing the weld and then breaking the tacks and grinding them off. This isn't always possible but it helps.

[Farmwelding]

Depending on the use of the part, you could take another thick plate and tack it to the base plate on this. If you need an example, Jody has a video about mig welding aluminum that demonstrates this with aluminum plate

[motox]

presetting can help as well. you will have to try a couple of pieces
to see how much set to put into the flat piece to end up with a near
flat finished surface.
craig

[Mike]

Chris, welcome to the forum.

[Poland308]

Leave a gap between the plate and the tube when you tack them togeather. Gives a little relief from shrinkage as you weld it.

[AKmud]

Clamp the plate solidly to a table or a strongback of some sort if you can, and don't un-clamp it until it has cooled completely.

[Arclight Ironworks]

....I am welding a 3"x.25" round tube to a 24"x24"x.25" plate, dead center. The material is steel and the process is TIG. I was hoping to hear some of your tricks for preventing the plate from "cupping" up toward the post on the side of the weld...

What can you tell use about the intended use of this welded item? Static, dynamic, cyclical loading? Access to oxy-propane or oxy-acet torch?

Option #1. Micro tack the 1/4in round tube to the surface of the 1/4in assembly plate. 4ea 1/2" long tacks at cardinal positions on the clock. Cut 2ea 3/32" TIG filler wires into 24" lengths. Set aside. If available, sever another section of 2ft x 2ft x 1/4in steel plate as fixturing for your 1/4in assembly plate.

Stack up, from bottom to top. 1/4in fixture plate + 3/32" TIG filler at third-points on the surface of the 1/4in fixture plate + 1/4in assembly plate. Clamp the fixture plate to the assembly plate, bi-diretionally. This sandwiched arrangement "preloads" the system and introduces a micro-camber. Note, a fixturing plate is not req'd and you can easily camber the assembly plate directly to your welding table.

Weld the unit in quarters (e.g. 12 to 3 o'clock, then 6 to 9, then 6 to 3, and finally 12 to 9). Allow unit to cool, completely. Unclamp the assembly plate from the fixturing plate (or weld table). Inspect and FlameStraightening, as required, via oxygen-pro/acet torch by applying heat to the BOTTOM of the 1/4in plate.

Option #2. Disregard the 1/4in fixture plate approach. PreHeat the tube and entire assembly plate to 150F. Tack, followed by weldout a la the above technique. Allow the unit to cool. Inspect and FlameStraighten.

Unsure if you are experienced with oxy-fuel and FlameStraightening. We could walk you through the baseline technique if you have access to the equipment.

Understand that you cannot PREVENT heat from doing it's thing. Ever. Even placing a Battleship or M1 Abrams Tanks on the system as fixturing will not prevent warping. Minimize, yes. Eliminate, no. Atoms within the Elements are of star dust. Strong and Agile like the HoneyBadger.

Approach heat as a "tool". Apply to your advantage to affect the geometry during weldout and minimize distortion. In this situation, TIME between welds and attack approach are your allies.

[WildWestWelder]

The first question I have is how much cupping are you willing to put up with. Second, what material is the 1/4" plate? Is it cold finished? If it is then good luck, never had any luck with that. If it is hot rolled (A36) you shouldn't experience very much cupping unless you need it absolute flat.

[PeteM]

I'd place the plate on the table, the frame on the plate, and clamp them together. Then place/clamp some aluminum angles inside the frame on the plate to sink the heat. Let the square tube take most of the heat.

Anything beyond that begs the question "How important is it?"

[Olivero]

Well.....

Weld it and beat the piss out of it? That's what I do

The idea of leaving a gap between the plate and pipe is good, I have done it that way.

You can minimize it by welding a little bit at a time. I have warped 3/8" flat bar just by welding on and on and on without stopping, then I beat the piss out of it.

[PeteM]

Weld it and beat the piss out of it? That's what I do



.

Reminds me of some botched up keel plates I used to get some times when the sub-arc seam welder was out of whack.

Supposed to be relatively flat. Actually shaped like a pringle!

[cjarnutowski]

Wow, first of all thanks to Jody for cultivating a very helpful community.

I have an OA torch. The plate is HR A36. We can safely assume the loading condition is static, these are columns to support conference tables which will be bolted to the floor at the plate. Not sure if I mistakenly stated the wall thickness of the tube as 1/4", but it is in fact 1/8" wall. There is no tolerance, the reason I want to prevent distortion is to make leveling the columns easier.

Nonetheless I am taking this as a learning experience. Would anyone mind giving me a quick overview on flame straightening in this situation?

My concern with preload is that I'm trying to bend the plate in 2 axis, essentially cupping the plate in the opposite direction. Seems difficult to achieve with just clamps.

Thanks!! Chris

[motox]

why don't you go ahead and weld one and see how much it cups.
then you will have a better idea what to do to correct the cupping.

or just beat the piss out of it when it done, can't go wrong there.....
there is always a bigger hammer...
craig

[exnailpounder]

....I am welding a 3"x.25" round tube to a 24"x24"x.25" plate, dead center. The material is steel and the process is TIG. I was hoping to hear some of your tricks for preventing the plate from "cupping" up toward the post on the side of the weld...

What can you tell use about the intended use of this welded item? Static, dynamic, cyclical loading? Access to oxy-propane or oxy-acet torch?

Option #1. Micro tack the 1/4in round tube to the surface of the 1/4in assembly plate. 4ea 1/2" long tacks at cardinal positions on the clock. Cut 2ea 3/32" TIG filler wires into 24" lengths. Set aside. If available, sever another section of 2ft x 2ft x 1/4in steel plate as fixturing for your 1/4in assembly plate.

Stack up, from bottom to top. 1/4in fixture plate + 3/32" TIG filler at third-points on the surface of the 1/4in fixture plate + 1/4in assembly plate. Clamp the fixture plate to the assembly plate, bi-diretionally. This sandwiched arrangement "preloads" the system and introduces a micro-camber. Note, a fixturing plate is not req'd and you can easily camber the assembly plate directly to your welding table.

Weld the unit in quarters (e.g. 12 to 3 o'clock, then 6 to 9, then 6 to 3, and finally 12 to 9). Allow unit to cool, completely. Unclamp the assembly plate from the fixturing plate (or weld table). Inspect and FlameStraightening, as required, via oxygen-pro/acet torch by applying heat to the BOTTOM of the 1/4in plate.

Option #2. Disregard the 1/4in fixture plate approach. PreHeat the tube and entire assembly plate to 150F. Tack, followed by weldout a la the above technique. Allow the unit to cool. Inspect and FlameStraighten.

Unsure if you are experienced with oxy-fuel and FlameStraightening. We could walk you through the baseline technique if you have access to the equipment.

Understand that you cannot PREVENT heat from doing it's thing. Ever. Even placing a Battleship or M1 Abrams Tanks on the system as fixturing will not prevent warping. Minimize, yes. Eliminate, no. Atoms within the Elements are of star dust. Strong and Agile like the HoneyBadger.

Approach heat as a "tool". Apply to your advantage to affect the geometry during weldout and minimize distortion. In this situation, TIME between welds and attack approach are your allies.

Do all this

[Arclight Ironworks]

@ cjarnutowski - you have an OA rig. Good. Oxy-Acet bests an Oxy-Pro rig for flame straightening because the highest flame temp is CLOSER to the torch's tip and you can deliver a tight/tight heat intensity without diffusing the flame over a larger surface area as with Oxy-Pro. Thermodynamics in action.

Watch/study the below video. Use a large cutting tip, straight edge, and apply heat along a given line at a steady rate. Use a spray bottle with water to quench the heated area after a run. If you need additional runs, apply heat ONLY after the plate is cool/cool to the naked hand. Flame straightening is art and science blended. Patience and practice mastering this technique will serve you well in the future.

http://www.youtube.com/watch?v=0BI6itb9IpA#action=share

[exnailpounder]

O boy..somebody trying to sell something again...

[Otto Nobedder]

O boy..somebody trying to sell something again...

The video ends with an ad, but the information is sound. I use to do structural steel, and cambering beams was a task I got pretty good at. Now that I work primarily in SS pipe and plate, I've become quite good at pre-loading or pre-fitting a joint to allow for the shrinkage.

Steve S

[clavius]

This has been posted before, and while it seems hokey, the principles are sound and still apply:

https://www.youtube.com/watch?v=2vuGlcbDwKY

Besides, I really like that evil Mr Distortion guy. May or may not address exactly what you are working on, but there is some good basic info here if you watch it and pay attention.

[Olivero]

Well. You could also do some stitch welds on the plate to the table, then when done, cut it off and grind the welds down. I have heard of that working really well.

[Otto Nobedder]

Well. You could also do some stitch welds on the plate to the table, then when done, cut it off and grind the welds down. I have heard of that working really well.

This only contains distortion until you cut it loose. The shrinkage occurred anyway. Every heard a tack go "SNAP" half-way through a weld? Why did it do that? Because welding metal affects it in some substantial ways.

Steve S

[Olivero]

True, the stress and shrinking still occurs but if you relive the stress prior to releasing the piece, I would think it would stay flat.

Say he stitched it to the able and welded the pipe on and then heated the shabang up to whatever temperature it is, 500*F? Something like that and let it cool naturally. It should stay flat.

I THINK....

[MinnesotaDave]

True, the stress and shrinking still occurs but if you relive the stress prior to releasing the piece, I would think it would stay flat.

Say he stitched it to the able and welded the pipe on and then heated the shabang up to whatever temperature it is, 500*F? Something like that and let it cool naturally. It should stay flat.

I THINK....

Pre-stressing the piece would be much faster in my opinion.

[homeboy]

This is a bit out of my league but I read pre-stressing as in shimming the plate edges and clamping for a slight concave prior to welding to compensate for heat deflection as one suggestion. Curious what would happen if you drilled a hole in the plate centered under the pipe min. 1/2in . Place the plate over a perimeter frame and drop the bolt thru the hole. Under the frame would need a solid cross piece strong enough to tighten the bolt to concave the plate as required. Weld on pipe and after cool release bolt. Have no idea if this would work. If it doesn't work beat the piss out of it with a hammer!!