flame straightening

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This is an example of how to flame straighten Tees.  These ones were cut from a twenty inch beam.  When split the tees bent convex on the flange side.  Often they go concave on the flange side.  The heating and shrinking took about 4.5 hours for the two pieces.  I used a water bucket with two rags and move from one end to the other while the two pieces were clamped against each other.  When I started there was about three inches between the mating flanges and slowly I was able to tighten the clamps until the flanges touched each other.   Welding is 10 mm fillets with .045 metal core wire.Last edited by MicroZone; 05-25-2007 at 11:24 PM.
Reply:Nice work, just curious, but what is that going to be installed on?  I see T's quite often but never really understood why a "T" would be chosen over a "I" beam.  Just curious for my own knowledge.   Again nice work, I never thought of that.  ~JacksonI'm a Lover, Fighter, Wild horse Rider, and a pretty good welding man......
Reply:These ones are for supporting some sort of sign.  The sign shop is across the street.  They purchased a split beam delivered.  When the beam arrives it is flame cut down the center of the web except for four or five spots along the length that holds it together.  When you cut the spots with a torch it pops apart.  I guess they had not realized that it had to be straightened.  Flame straightening is one of my specialties.  The main thing it to THINK before applying any heat.
Reply:Nice work Randy, I like to see different stuff like that versus welds, welds, welds.John -  fabricator extraordinaire, car nut!-  bleeding Miller blue! http://www.weldfabzone.com
Reply:You use the wet rag right back on the spots you heated or give it some time first?? That's good work. Looks like they just came out of the box brand new. 4.5 hours would make me a mental wreck. I've practiced some of the flame straightening for things for myself. I was impressed with the results but it kills me waiting.
Reply:The sequence in heating and cooling is important.  You want the largest gradient of heat between the cold areas and the are you are heating.  Ideally I would have a helper with a siphon gun working at the same time.  In this case I heated the pie section until it was dull red.  I had the Tees on horses propped so that the web was horizontal and I could heat both sides of the web with the torch.  The last area to lose the red heat should be the wide part of the pie section.  Once red I laid one wet rag on each side of the hot metal to accelerate cooling and keep the black steel as cool as possible.  Do not quench the red area... let it cool naturally.  Once the area is black you can dump a soaking wet rag right on top.  Until the metal is room temp you don't really know how much it moved.  If I had a helper on a siphon gun he would be shooting wet air on the outside face of the flange while I heated the pie section.  Once red he takes over on the web area and cools the area next to the red by moving his gun back and forth in a Vee pattern just outside the red area chasing the red from the flange out toward the flame cut edge.   Meanwhile I jump along and start heating another pie section.   Also with a helper would have the Tee set between horse standing up, flange down with gravity trying to straighten it.  For extra effect you put a com-a-long from the middle down to the floor attached to a steel plate imbed in the floor.Last edited by lotechman; 05-26-2007 at 03:21 AM.
Reply:A true professional metalworker.DavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:nice work its good to see guys that still  know how to do stuff like thatChuckASME Pressure Vessel welder
Reply:Great explanation. It sounds very similar to what I have to do to rear-end housings that are out of alignment.Nice job lotechman.- Paulhttp://all-a-cart.comWelding Cart Kits and accessories
Reply:Do not quench the red area... let it cool naturally. Once the area is black you can dump a soaking wet rag right on top. Until the metal is room temp you don't really know how much it moved.
Reply:As I mentioned it is wise to think before applying the heat.  A motto that was told to me :  The hot side becomes the short side.   To cool the item back down to room temp an air siphon gun drawing water into the air stream is very effective.  yes it is wise not to rush the process.  The best tactic is to do a heat shrink then leave it alone and do some other job until it is room temp and you can check it with the eyecrometer.  That movement the wrong way when you initially apply heat is indeed alarming for the beginner.  The principle behind the process is that as you are heating the cold area opposite is restricting movement.  Once the area is red hot the cold area stops any more expansion so the red area is upset since it is soft like toffee.  When it cools back down to black it is now too short to fit into the original area so it pulls stretching the cold area putting the cold area in tension.
Reply:I used to bend ornamental cap rail the same way.  Always seemed to me the contraction was greater than the expansion.There were points when the metal wouldn't do anything without much force and I would have to let it rest and come back.Thanks for sharing.
Reply:[QUOTE=tapwelder]There were points when the metal wouldn't do anything without much force and I would have to let it rest and come back.QUOTE]There are some situations that you would want to forget.  This is a picture of an assembly that humped upward at each pipe location on the beam.  I had to shrink the beam straight after welding.  The pie shaped heats had to happen on each side of the big pipes.  Big rosebud on propane and siphon gun ... lots of water all over the floor.  We got smarter on the next pair and clamped/tacked back to back before welding.  The weld shrinkage was less so it made life a lot easier on the flame shrinking.  By the last pair we had it all figured out and clamped back to back and shimmed the middle out the width of two 2 by 4s.  At that point the flame shrinking was minimal and only took a few hours.  PLEEZ!  Lets not talk any more about the first one! Attached Images