metal warpage during welding

[1930artdeco]

DIY beginner welder here with a warping question. Is it possible to determine if the metal at a weld will either raise or lower due to warpage by looking at the seam where the two metals meet? The reason I ask is this, I just did a but weld (steel to steel-19 ga.) and I thought both pieces were level or just slightly higher/lower. Slowly did my tack welds all the way around being careful to not let the metal get too hot. I noticed that one corner and partially that side 'dipped down a bit'.

Now I did not clamp the two pieces together as they fit so well together that I just zapped them together. Great and kept on going. Then I noticed as I continued on that one corner dipped down a bit-plus I could hear it either popping welds or kreaking somehow. Would a clamp of some sort prevented this from happening?

Thanks,

Mike

 

[rsanter]

First you need to think about what you are doing when you are welding.
you are adding molten hot metal to cold metal. The arc heats the cold metal and allows the deposit of the hot filler metal to the base metal.
all that metal now cools and when it cools it shrinks.
the shrinkage is what causes the warping. There are some tricks to reduce or minimize the warping.

geometry. Where and how you put the patches in.
gap, having an even minimal to zero gap will minimize warping or at least keep it even.
heat, not overheating the weld. You don’t want to weld cold and have poor penetration but you don’t want more heat than needed.

and old school trick that many people do when welding on car bodies is hammering the weld.
some people will weld a stitch (short section of weld) then They will hammer and dolly the weld. Hammering the weld while it is still hot takes advantage of the heat to flatten and expand (stretch) the weld area to counter the shrinkage

other will anneal the weld after all is done. If you reheat the mig weld with a gas torch to TIG torch you can relive some of the weld shrinkage stress out of the weld and you also can hammer and dolly the heated well (same like above)

typically a mig weld is harder than the base metal. Hammering when hot means the weld is not as hard at that time and reheating (annealing) the weld will also serve to remove some of the harness from the weld and make it easier to work.

understanding what’s happening to the metal is essential to becoming a welder. That really the difference be someone who ‘welded’ and some that is a “welder “

 

[kctgb]

That isn’t very thick metal, it’s going to bend as soon as you put heat on it. I’ve seen 3/8 and 1/2 inch plate bend after 10 minutes of welding on it. When the weld puddle cools it shrinks pulling the base metal with it.

 

[T444e]

I've seen either 3/4" or 1" plate (can't remember which) warp from welding.

 

[22george]

First you need to think about what you are doing when you are welding.
you are adding molten hot metal to cold metal. The arc heats the cold metal and allows the deposit of the hot filler metal to the base metal.
all that metal now cools and when it cools it shrinks.
the shrinkage is what causes the warping. There are some tricks to reduce or minimize the warping.

geometry. Where and how you put the patches in.
gap, having an even minimal to zero gap will minimize warping or at least keep it even.
heat, not overheating the weld. You don’t want to weld cold and have poor penetration but you don’t want more heat than needed.

and old school trick that many people do when welding on car bodies is hammering the weld.
some people will weld a stitch (short section of weld) then They will hammer and dolly the weld. Hammering the weld while it is still hot takes advantage of the heat to flatten and expand (stretch) the weld area to counter the shrinkage

other will anneal the weld after all is done. If you reheat the mig weld with a gas torch to TIG torch you can relive some of the weld shrinkage stress out of the weld and you also can hammer and dolly the heated well (same like above)

typically a mig weld is harder than the base metal. Hammering when hot means the weld is not as hard at that time and reheating (annealing) the weld will also serve to remove some of the harness from the weld and make it easier to work.

understanding what’s happening to the metal is essential to becoming a welder. That really the difference be someone who ‘welded’ and some that is a “welder “

Good information. Hadn't thought of annealing the weld.Thank you.

 

[Rockable]

Good information. Hadn't thought of annealing the weld.Thank you.

Dont try that as a beginner. Try controlling the heat affected zone (haz) and the fit first. Make a tack. Grind it down close to flat without putting too much heat in the panel. Hammer it down against a dolly to stretch it back out. Then, make another tack. If you space them about an inch apart to start with, you can then go back a put one in between. After that, "stack a tack". The heat on your welder should be high enough to give good penetration with a shor burst of weld. Practice. Remeber, every weld shrinks. Try to minimize it by stretching the weld.

You cant really anneal a mig weld. Carbo is added tomit via the gas. Someone with a lot of experience might be able to but you cant.

 

[Jacko264]

Hi
I know its not steel but i use to weld aluminium floors in 40 foot trailers and to stop the sheets of aluminium warping i use to put a 2.5 mm gap to give the sheets room to expand .
also tacks all the way not long welds

 

[tncatadjuster]

Practice helps with learning what and how to minimize.

 

[tarbellb]

This

Jody breaks it down, makes it very easy to see whats happening

 

[kctgb]

This

Jody breaks it down, makes it very easy to see whats happening

Sad to see Jody not doing so well, hope his health issues get better.

 

[danielbuck]

I've seen either 3/4" or 1" plate (can't remember which) warp from welding.

if you get parts of the metal hot enough to weld, it will warp regardless of size.

 

[BORING HOP YARD]

I would like to make a recommendation to you. Take the time and read the thread below, it has the information that you're looking for. Robert does a really good job of explaining what's going with the metal.
https://www.garagejournal.com/forum/threads/welding-in-patch-panels.53534/

 

[zimman]

Just takes time to learn. Tac on side and it pulls, tac the other side and it pulls it back. On thinner stuff you can have a wet rag ready to cool the run, short runs only. Halt inch at the time. Prepare for days not minutes in welding. LOL TIG is a bit cooler to weld for me.
Zim

 

[American Locomotive]

I've been doing a lot of body work the past couple of years on a long-term project, and I'm just now starting to come down with a process to minimize warping.

One thing that has helped me is to turn the welder power up, but use shorter bursts. Just very quick tacks at a pretty high power/wire feed speed. I have found that this seems to allow the tack to fully penetrate the weld seam, and prevent a big bead from forming up top. Since the weld is more symmetrical on both sides, it seems to reduce pulling/distortion. I also found that if it does bead up, quickly hitting it with angle grinder while it's still hot also seems to help. The trick is that at higher power settings, it can be easy to just instantly pop a hole through the metal, but with practice and tweaking you'll be able to ride the edge.

Globbing a giant bead on top that doesn't really fully penetrate (say if your welder is set low current, because you're worried about burning through) seems to be the worst for distortion.

 

[jmdirk]

I would like to make a recommendation to you. Take the time and read the thread below, it has the information that you're looking for. Robert does a really good job of explaining what's going with the metal.
https://www.garagejournal.com/forum/threads/welding-in-patch-panels.53534/

This and MP&Cs general fab thread. You'll learn more about welding and sheet metal reading through his stuff that you will watching 100's of hours of YouTube videos. The guy just really understands how metal moves.

 

[nadogail]

When you apply enough properly placed tack welds, they will work together to neutralize distortion and stop movement of the welded joints.

How many tack welds? What should the spacing be? The answer will come to you as you gain experience,

 

[Fixr]

When you apply enough properly placed tack welds, they will work together to neutralize distortion and stop movement of the welded joints.

How many tack welds? What should the spacing be? The answer will come to you as you gain experience,

I recently had a welding project where I really wanted to avoid distortion of some light plate edge-welded to angle. So I did a few tacks on one side, spaced well apart and not all in a row one after the other but back and forth from one end to the other and in the middle. Repeated on the other side. And then back and forth, flipping it back and forth trying hard to keep the heating and cooling even.

Massive failure. Warped all to hell like a series of potato chips. I'm frustrated.

Fortunately, it won't be going into a nuclear power plant, or even a vehicle.

 

[nadogail]

I recently had a welding project where I really wanted to avoid distortion of some light plate edge-welded to angle. So I did a few tacks on one side, spaced well apart and not all in a row one after the other but back and forth from one end to the other and in the middle. Repeated on the other side. And then back and forth, flipping it back and forth trying hard to keep the heating and cooling even.

Massive failure. Warped all to hell like a series of potato chips. I'm frustrated.

Fortunately, it won't be going into a nuclear power plant, or even a vehicle.

There will be like that, My Moma said.

 

[Opa]

here is a you tube link (I hope I did this right) that I found helpful in how to use heat to straighten (remove) warpage after welding.