Welding Warpage

[lewis]

Welding up my sliders and they are warping due to the heat from welding them. I tried to outsmart the force of heat by welding a a big piece of angle iron to the slider when I was welding the kickouts to the frame and it looked good til I cut the welds off after it had cooled. I still have to weld on the dimpled piece and last time it twisted the crap out of it. What can I do to help prevent this? Here is the pic of it tacked on. I remove it ot finish welding it.

 

[STAG]

Well, one trick to prevent warpage and burn through is to stick a chunk of copper on the backside of the material at the area being welded... I would say if you got a 6" long peice of copper you could do 6" long stitch welds at a time, cooling the copper in a bucket of water in between each weld pass.. it would take a little bit to do it 6" at a time but you wouldn't warp the metal.. (how it works is it draws the extra heat that isn't used in the weld (which usually just heats up the metal around it) and the softer copper soaks up the up the heat and retains it...)... I'll post a link from OFN with some more pointers one sec..

 

[Bucking Bronco]

Have you tried just welding 1 inch welds spaced about 1 foot apart? Its tedious and not usually pretty but it should work.

 

[jswainthug]

I would just jump around. Do the front top then the bottom rear in small sections letting it cool in between.

 

[STAG]

Yeah I got thinkin about it and the copper would be a bit of a hassle for this much welding... so what I'd say is just have a wet rag and a bowl of water nearby and weld 3 inches or so and jump around... and because this isn't structural you would be fine with touching the wet rag to the weld after welding it to cool it quickly... lots of people do this...

 

[lewis]

I thought about doing it in small segments but its sooo hard to stop with a nice bead going. Everytime I stop, when I start again my beads looks different. I would rather it the weld look a little off then the whole slider twisted like a pretzel stick.

 

[Bucking Bronco]

I thought about doing it in small segments but its sooo hard to stop with a nice bead going. Everytime I stop, when I start again my beads looks different.

Same problem I had doing the roof of my buggy so I just made the welds a little thick and spent some time with the grinder smoothing things out.

 

[cheepin]

Only thing to do is.Weld in small sections and jump around letting it cool before going back to a previous weld.

 

[420willys]

back stepping the welds helps with warpage. start on the end and then weld into each start. make the welds the same length ( lets just say 6"s long each ) and it should help with warpage. maybe welding the two sliders back to back. then back stepping the welds and flipping them from one slider to the other.

its not so much the heat that warp's the metal its the cooling of the welds that shrinks the steel around it self and pulls the molicue's ( how ever its spelled )together.

the other thing is fit. if its fitted together with large gaps this will take more filler wire to fill and then put more pulling force on the welds to shrink when they cool.

jason.

 

[MikeGyver]

Thermal contraction is gunna happen no matter what.
About all you can do is take this into account while fitting so your work trues up after welding, press/bend the work flat afterwards, or use proper opposing thermal contraction afterwards.

I've seen little advantage in doing excessive staggering welds. The same amount of thermal energy is still being put into the work and it's still cooling at virtually the same rate. As stated, the heat isn't what pulls. It's the re-solidification of the metal. Keeping the workpiece cold isn't going to do much.

The order of which the weld is applied can also greatly effect certain instances. For example if 90degree T joint is completely welded on one side before the other, it's going to lean toward the first weld, Whereas if both sides are adequately braced with small stitch welds it will control the initial pull.

 

[Shawn]

I like those, cool.

 

[lewis]

Been welding them 3 inches at a time and its taking forever.We'll see if thats any better in awhile when I get them done.