Tough question... how do you predict/combat warping?

admin

How does one predict or combat warping in their weldment?Are there any books on fabrication that go into depth on this?I know I'm opening a can of worms here, but I gotta start somewhere... My textbook doesn't even touch on this subject...
Reply:Originally Posted by TaidenHow does one predict or combat warping in their weldment?Are there any books on fabrication that go into depth on this?I know I'm opening a can of worms here, but I gotta start somewhere... My textbook doesn't even touch on this subject...
Reply:Excellant excellant article, doing any sheetmetal?or just weldments in general?Can also lookup stress relieving.http://www.lincolnelectric.com/knowl...distortion.asp
Reply:It's all about heatAny weld will contract/shrink as it cools, in turn pulling on the weldment.  This is distortion.Welding on diagonal patterns, matching welds on top of and underneath joints, etc......all help to alleviate the worst effects of distortion.  BUT YOU WILL GET SOME DISTORTION EVERY TIME YOU APPLY A WELD TO MATERIAL.By looking at the job, and trying to predict the pulling effects, you'll get some idea how to proceed.  Basic info is covered in the Bible (as others have mentioned above).A good approach is to try to counteract every force with an opposing force.  Fight shrinkage with shrinkage.  Restricting joints may help to some degree, but there will still be shrinkage, which in extreme cases could lead to weld bead failure from cracking.  Preheating can help reduce the effects of shrinkage.  And if all else fails it's time to get out a heating tip and "heat shrink" the structure back to specs.  The most successful approach is to balance shrinkage with shrinkage (sounds stupid until you've seen the effects, or had a real disaster)Another approach, when feasable, is to pre-stress the weldment in order to allow for shrinkage.When you see something pull after you weld it, don't sit there and pull your hair out.  Analyze why it pulled, and try to figure out how an equal amount of heat(a weld) applied to another area of the weldment will help to pull it back to shape.  This will teach you how to sequence multiple welds to counter distortion caused by preceding welds in the same sequence.  This learning process also transfers over to weldment design."Any day above ground is a good day"http://www.farmersamm.com/
Reply:The way I generally understand it is there are a few things you can do to prevent warping in general.  -Always- tack your welds together, every 4 inches or so, lay down a quick tack on the joint you are about to weld.  It can be tedious, but it would prevent a lot of warping, at least on the joint itself.Keeping things clamped together as much as possible will help as well, metal that is clamped down won't warp as easily.It is important that you note what you are clamping your work to.  I think the best thing you can clamp your work to are pieces of thick angle aluminum, this keeps the temperature on the area around the weld more reasonable as much of the heat goes into the angle aluminum.  These details are assuming that you are working with sheet metal.  I don't know what to tell you about other kinds of setups, like tubing.Some say that pulse welding is supposed to do great things for preventing warping, I know it's a great way to make the stack of dimes look come super easily.  I feel that there is probably going to be at least a little warp-age, but it can be avoided for the most part if you do these things I just suggested.Miller 330 a/bp water cooledI believe in gun control, I hold my gun with two hands.  If you want to know why, click here.Buy American or bye America.
Reply:Just weldments in general. I'm concerned about things like welding a table top support and having it be flat, stuff like that.Here's a picture of what I'm planning, and I want it to be as flat as possible.
Reply:Build the table frame as a seperate stand alone unit, heat shrink it back to straight, then tack/stitch weld the table top thingys on, then shrink again.Shrinking can be accomplished either with a torch and rosebud (possibly just a cutting tip), or backbeading(welding in order to place heat on opposite sides, then grinding the welds off)A great hands on learning project"Any day above ground is a good day"http://www.farmersamm.com/
Reply:could i just heat it with a TIG torch? I have no oxy/fuel bottles.
Reply:No dive in and do some welding.I've built a few things like this for myself, make sure table/surfaces are straight and level to begin with, don't overweld and weld some nuts to the bottoms of the legs so you can make levelers.Anything like a grinder stand I make with three legs instead of four.