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Gents--I have 16 pieces of 1/2" thick plate, 9" square, that will be welded to 4x4x3/8 square tube columns, each plate will have 4 gussets located in the center of column. I plan to MIG well all. I had considered tacking the gussets on a bench with jig prior to welding the plate to the column to use as a centering method. I would be indebted if I could solicit some of your expertise on any tips you might share on avoiding distortion of the 9" plates, these supports will be attached to a foundation with j-bolts I expect some distortion and use shims to square up, I'd just like to keep it to a minimum. Recommendations would be greatly appreciated, in advance thank you.
Reply:Clamp or bolt another plate on the back of the base and alternate your welds. if you can bolt two of columns together and then you can really alternate the welding to limit heat input. I would tack the base plates on and then tack the gussets on and weld together. You could put little welds where the gussets fit over them if you wanted.
Reply:Hello 200mphbusa, most shops would simply tack everything up and weld it out. As you are going to be mounting these to J-bolts that are likely cast into concrete there is generally little to worry about if the construction is by an experienced erector. I put it that way because where most columns are connected in the manner that you are describing. However, leveling nuts are generally put onto the studs first and shot-in and set to grade, then the columns are placed over these nuts and additional nuts/washers are run-down and torqued. If any additional plumbing of the columns is required the nuts are loosened and tightened accordingly. Then non-shrinking grout is used to fill in under the plates to complete the set-up of the columns.If you are concerned about doing what you can to keep things as un-distorted as possible you could fully tack the plates and gussets to the bases of these columns and then bolt 2 columns end-to-end with a small spacer in the center of the flat-side of these mounting plates and draw them down tight, then proceed with welding them out. After cooling, take them apart, this will minimize the distortion that would be present. The thickness of the shim however, is something that experimentation can only prove out, my first suggestion would be a washer of roughly 1 1/2" to 2" in diameter placed in the center with a little bit of tape to keep it there while bolting them up. As I did mention innitially, most shops would simply weld them up. Unless they were stainlesss steel, then they might pay some additional attention to distortion issues. Good luck and best regards, Allanaevald
Reply:preheating from the underside may help a tiny
Reply:AEVALD hit the nail on the headVantage 500's LN-25's, VI-400's, cobramatics, Miller migs, synch 350 LX, Powcon inverters, XMT's, 250 Ton Acurrpress 12' brake, 1/4" 10' Atlantic shear,Koikie plasma table W/ esab plasmas. marvel & hyd-mech saws, pirrana & metal muncher punches.
Reply:I recently pondered this question. Preheat will help. but I suggest post heat. No pun, After welding, heating from below with a rosebud tip will expand the metal on the underside. You may find a hammer necessary when hot, but shrinking as it cools should bring it back to shape. Another tactic you could use is begin by welding or bolting two plates together, Attach two posts, and gussets, then separate.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:ya, i'm w/ you on your theory. but welding on cold steel instead of hot, end result the cold will have pulled a lil more
Reply:Aevald's got it. Two base plates with a spacer in between, tighten them up so they are distorted in the same amount and opposite direction that you would expect the weld to pull a flat plate.Ian TannerKawasaki KX450 and many other fine tools
Reply:Gents--thank you to each of you for sharing your expertise and experience, it is much appreciated. Because my shop is limited in space, placing the columns end to end won't be possible, but I will try the technique of placing an adjacent plate with a spacer in the center and clamped as recommended. I'll experiment with the preheat also and try a couple. I'll report back to you on the outcome, again thanks for taking the time to help out.
Reply:Weld it then beat it.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:if i am picturing your setup. pre-bow your base plates by shimming like the others said. then when welding your gussets start from the outside and weld to the inside corner... have done alot of support posts, motor mounts etc like that. works great.. good luck! pics when done?
Reply:In the structural steel field, nine times out of ten if your welding a 3/8" HSS to a 1/2" base plate you shouldn't have to worry about it getting warped. Your weld size should be 8mm and if you can lay down a good weld all the way around, then you don't have anything to worry about. "Just weld it up".
Reply:If you had a helper, you could get them setup. To do the layout, and preheat the plates for you. I would use a # 3 or 4 cutting tip, a straight edge, and heat red hot. Once the square is red hot, throw the plate on the ground and cool with a water hose. Be sure you cool the side that was heated. Then weld the square tube to the opposite side. Attached ImagesDont pay any attention to meIm just a hobbyist!CarlDynasty 300V350-Pro w/pulseSG Spool gun1937 IdealArc-300PowerArc 200ST3 SA-200sVantage 400
Reply:AS Tat2 implied, don't over-weld.Hobart Beta-Mig 2511972 Miller AEAD-200LEMiller 250 TwinNorthern Ind. Hybrid 200Longevity Stick 140Longevity Migweld 200SThermal Arc Pak 3XR
Reply:Can you test the following method on a test piece. cut a 4x4 inch hole in the center of the 9" plate with the same radius as the tubing. slip fit the 9x9" "ring" over the tubing and use small angles to clamp the 9x9" square to the center line of the 4x4 tube, I would leave alittle open corner joint gap to fill. tac everything in position on both sides. fully weld out the 4x4 & 9x9 on the bottom side as there is very little leverage to warp the 9x9. Hopefully you can bevel out a nice groove and weld the piss out of it. Essentially the same amount of weld by doing a butt weld from the top side but without warping the 9x9 base plate. You might still be required to weld out the entire top side to prevent places for water to collect and rust over time. This is where you always get the taco warping effect. Maybe you can do minimal welding on the top. good luck
Reply:Is there a specified fillet weld size that you must achieve? What kind of stress will this weld have to endure, when put into action?The reason I ask, is because I have welded at least a thousand of these machinery mounting brackets (mostly 3/4" - 1" thick). In the beginning, I used to mig weld them, because it is quick. But, they'd distort. Then I tried tig welding them. The bead size was greatly reduced , as well as the distortion. They have a fairly big job to do, when put into action. Not a one has ever broken.That being said, these assemblies do get machined square post-weld because they really have to be precise, but there isn't much to cut to get them square. Not like there used to be when I used to mig weld the whole pieceAnd, I also don't fully weld them...I do mig weld the back side bevel, though..That may or may not be an option to you...Rich |
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发表于 2021-8-31 22:36:19