Help with warped 1" plate

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I have this assembly that is a 7.5" OD pin in the center with a 1" A36 plate/washer. There is a 1/2" weld that stops 1/2" short of the 2" cross pin. There is also the 4 gussets. When if welded this piece inlet it cool between passes but it still warped the 1" plate down roughly 1/4" on the outside.Does anyone have any suggestions on flattening the 1"? Does not have toBe perfectly flat, but as close as I can get it. Dynamic MetalworksMontrose, CODynMetalworks.com
Reply:If you are going to but mounting holes to bolt the circle to the ground won't it flatten out while tightening? Assuming the anchors don't pull out of course... If not, then heat shrinking?Precision TIG 225MillerMatic 250Powermax 35XPPowermax 65TM 4X4 w/ water tableLagun FTV1Monarch 10EEJD2 M3 with hydro conversion
Reply:A large plate goes over the pin and spins against the 1" washer, so no bolts. I've thought about trying to straighten with heat, I just have very little experience with that.Dynamic MetalworksMontrose, CODynMetalworks.com
Reply:I take it as the plate curled up as in the first picture? If so, this is gonna be tough. Do you have two #12 rose buds? I would heat a donut on the bottom side of the plate. Inside of the donut would be the pin. Heat the ring red hot, and a little wider than the gussets on the top side. Once this area is red hot, take a garden hose and cool the area with water. Lay a straight edge on it to see how far it moved. If need to go more, make the heat ring bigger. Don't do this until the plate is completely cold to the touch. Attached ImagesDon’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:You can increase the shrinkage effect if you use a siphon gun spraying an air water mix on the top area while you heat the bottom surface of the plate.  An alternative is to duplicate the fillet weld heats by running beads on the opposite side.  Again it will work better if the side that has already shrunk is kept cold by spray or wet rags.
Reply:did we forget about using the needle gun to peen the welds or just jump to the heat ? I have forgotten now .
Reply:Originally Posted by lotechmanYou can increase the shrinkage effect if you use a siphon gun spraying an air water mix on the top area while you heat the bottom surface of the plate.  Again it will work better if the side that has already shrunk is kept cold by spray or wet rags.
Reply:Thanks everyone for the input. How much will the rapid cooling affect the strength of the plate/weld?Dynamic MetalworksMontrose, CODynMetalworks.com
Reply:This is a homemade siphon gun.  The hose goes in a bucket of water and you spray.If your plate is A 36 it will have minimal effect.  Other structural alloy plates can be affected.  I doubt you have the new family of plate that appearing.  It has no grain direction because it is rolled at a temperature lower than normal causing the grains to fracture into smaller grains that are no longer elongated.  The alloy is doped with rare elements to ensure that it does not fracture when rolled at lower temp.  The yield strength of these alloys goes way up but if you heat to a red the grain grows and you lose the high yield strength.   Shrinkage and distortion is increased the greater the temperature difference between the red hot area and the surrounding cold metal.  When you heat shrink the red hot metal expands but is restrained by the surrounding colder metal so it swells in thickness.  As it cools from that malleable state it shrinks pulling the surrounding metal towards itself.  If you are smart when you heat shrink heat the area red then cool it with wet air spray or rags applying the cooling to the area around the red,  Don't quench the red area. That is a waste of time and effort.   In the case of that plate you can increase the shrinkage effect by water spraying one side of the one inch plate while heating the other side to red.  I have pulled out kinks in large beam flanges using this technique.   Acetylene is the best for heat shrinking however you run into the problem of a limit in the amount you can draw off a acetylene tank.  MAAP gas is best compromise since it is hotter than propane and you can concentrate the heat more easily.  I have used propane and even natural gas with oxy to shrink but it is not as easy.Last edited by lotechman; 09-06-2014 at 11:04 AM.
Reply:lotechman I seen one of those siphon guns used one time.The guy who taught me how to heat shrink, learned from and helped the guy do the beams on the Seattle Space Needle. Years ago I was in the raising gang sheeting an 80' x 80' x 70' tall building at the Boeing Space Center in Kent Washington. We sheeted the inside of the building with 4' x 8' x 10-GA sheets. All four walls, ceiling, and floor. 100% welded with .030” Mig. When the floor got welded you couldn't hardly walk on it. Boeing would not allow the sheets to be anchored to the concrete floor. Company I was working for brought in the guy who taught me how to heat shrink, to heat shrink the floor. He took a warehouse forklift, drove it onto a 6” x 6” angle iron. Took a very large oxygen & acetylene welding tip heated a 6 on 12 line at the heel of the angle iron. He had a kid cool the heated line with a siphon gun with a 5-gallon bucket of water. I'll bet it took him at least a month, but when he was done the sheets on the floor were as tight as the skin on a drum!Don’t pay any attention to meI’m just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:I saw a rig laying in a shipyard which was  a bar with flame holes all along it with a handle much like a floor broom.  The guys told me that they used it to shrink deck plate to take out the buckles.  Never saw it used though.   A word of caution here:  Many new alloys do not take kindly to heat shrinking or you are limited in the temperature you can use as dictated by the engineer.  I would just look at the alloy and if it was low carbon like under 0.4% I was good to go.  Not any longer.  For rough ironwork it is no problem but if you are working to structural code you have to be careful.  Putting camber on beams by heat shrinking was standard method.  On many current jobs the engineer will only allow bending the camber on a press.