Hi I'm welding some heavy duty brackets out of 10mm steel, I'm tacking base plate to bench in all 4 corners & also tacking a brace plate actress the top of the 2 plate but after cooling when I cut the tacks it has still warped by a good 3 or 4 mm, what am I doing wrong? And how can I fix this. Any help would be appreciated.apoligies for my rough drawing lol.
- Thread starter ruffets
- Start date
The issue is you have weld shrinkage as well as the new section shrinkage. you could preheat everything after tacking, this should help. you could also eld the first side, slightly off so it pulls vertical as it cools, then preheat and weld hot. Bit of a faff....
Cheers m8 Il give it a bashYes,tack flat min 10mm under base, flat to flat (not a90 degree edge on),keep top brace. Nice hot tacks. Hope this helps.
Unfortunately I don't have burning gear I can't preheat I was welding the outside welds first before welding the insides, thinking of the pulled they would pull outwards (which wouldn't be as big a problem)
Screwdriver
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If you can't preheat the workpiece, you could run a couple of hot beads on the rear to pull it back into shape, then grind them off.
I'm bracing the uprights at the top then welding outsides first instead of presetting so they would pull outwards if anything, the main prob seems to be the base warping which is kicking them in, I will try tacking base down to thicker material (not having access to burning gear or any form of preheat) I will try the run across the back to see if that pulls it back into line and keep a big hammer close by for some brute force & ignorance
Unfortunately I have no access to any form of preheat and I was welding the outsides first to Pull uprights out a bit which wouldn't matter so much, seems to be the base which is causing me problems ...
JOEPRO
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Rothenberger superfire 2 torch on MAPP gas should be enough to pre heat
Screwdriver
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I might be wrong but I thought stresses build up in such situations so that when released, the stress dissipates itself by deforming anyway long after the part has cooled. I believe you would need to hold the workpiece in place then heat treat it to remove the stress before knocking out your supports.
<edit> I have heard tales of tapping away at welds so that the vibration causes the stress to dissipate as the hot weld cools. Think I remember seeing that on cast iron welds in particular.
I don't know is this will help or not, when I was much younger and first started off welding I did about 8 months in a tractor/earthworks company making the arms and bucket for mainly smallish agricultural equipment such as tractors with front buckets and some times larger excavator buckets. in the smaller versions the bucket was made out pre-pressed (sort of C shaped)) 5/16"+ inch steel, after marking it out we would tack weld a metal pad (in the correct position) about the same thickness on one end of the pad to the bucket, then weld a longish bar and use the leverage to bend it around the shape of the bucket once we tacked and bent the pad to the shape, ( sometimes a rosebud torch was involved) we would then remove the bar, fully welded the pad, cleaned the pad up and tack welded the 2 sets of 2 x 3/8"plates that held the ram ends, there was a hole in the middle of the plates the size of the ram end bolt holes and a larger pipe put in over the shaft between the two sets of plates, and another shorter pipe put in between the each pair of plates, then tightened them all up, we would do a a pair of plates at each end of the bucket. Once, tacked and positioned we then proceeded to weld the ram plates to the shaped pads.
First weld was only half the plate length on the outside, then a full length weld on the inside and finally the first missing half was welded. Once cooled we didn't seem to have a problem with the plates bending in or out once we removed the shafts and pipe, it probably also helped that the mounting pad was welded in circular shape on the bucket. I do vaguely remember that they may have reamed out the holes to make them precise fits but I never really paid much attention to that as that was not my job. I then welded on a length of oversized wear plate for the front edge of the bucket, heated the ends over with oxy/acet rose torch and bent the ends to fit the front of the bucket with the help of a B.F.G. Finally a few more skid wear plates to the bucket bottom and sides and my job was complete.
Another site I was employed at, did large structural beams and where they put reinforcing plates in place between the webs , there would be some deformation in the beams. The boiler makers use to oxy/acet heat the area and then pour cold water to shrink the beams and webs straight, couldn't get too much info out of those guys as in those days they were qualified boilermakers and I was a lowly class 2 welder. Very unfriendly towards us would be an understatement and heaven forbid they would part with any knowledge!
First weld was only half the plate length on the outside, then a full length weld on the inside and finally the first missing half was welded. Once cooled we didn't seem to have a problem with the plates bending in or out once we removed the shafts and pipe, it probably also helped that the mounting pad was welded in circular shape on the bucket. I do vaguely remember that they may have reamed out the holes to make them precise fits but I never really paid much attention to that as that was not my job. I then welded on a length of oversized wear plate for the front edge of the bucket, heated the ends over with oxy/acet rose torch and bent the ends to fit the front of the bucket with the help of a B.F.G. Finally a few more skid wear plates to the bucket bottom and sides and my job was complete.
Another site I was employed at, did large structural beams and where they put reinforcing plates in place between the webs , there would be some deformation in the beams. The boiler makers use to oxy/acet heat the area and then pour cold water to shrink the beams and webs straight, couldn't get too much info out of those guys as in those days they were qualified boilermakers and I was a lowly class 2 welder. Very unfriendly towards us would be an understatement and heaven forbid they would part with any knowledge!
Memmeddu
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I'd try to
Tack two pieces of flatbar beneath the base , with the side on the base ,in perpendicular direction to the upright plates .
Tack the uprights and tack something to prevent them to spread or close , keeping the square.
Preheat.
Then splice the welds .
Like a 120mm bead, will become 3 40mm beads .
40mm on a side ,40 on the opposite .
Finishing to weld where the previous bead starts.
Once cooled, you remove all the bracing and the warpage should be minimal.
If it's still not acceptable you have to heat the welds after finishing prior to remove the bracing to reduce the distortion once cooled down
Tack two pieces of flatbar beneath the base , with the side on the base ,in perpendicular direction to the upright plates .
Tack the uprights and tack something to prevent them to spread or close , keeping the square.
Preheat.
Then splice the welds .
Like a 120mm bead, will become 3 40mm beads .
40mm on a side ,40 on the opposite .
Finishing to weld where the previous bead starts.
Once cooled, you remove all the bracing and the warpage should be minimal.
If it's still not acceptable you have to heat the welds after finishing prior to remove the bracing to reduce the distortion once cooled down
