metal bowed after welding (2025)

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paul taylor

New Member
Messages
4
Location
Raunds, uk
  • May 22, 2016
  • #1

Hi All. I have made a pair of driveway gates from 60x30x3mm box mild steel. I have welded a 30x30x3mm angle iron to 1 of the uprights to act as a stop, I have only welded 1 side along it's edge as I thought this would be sufficent, but it has pulled the steel from straight by about 10mm over 1.8m in length. If I was to weld the other edge, will it pull it back straight or am I better off cutting the angle off & start again( (I guess by just removing the angle iron it won't straighten itself?)

Thanks in advance for all replies.

Paul.

J

J.F

Member
Messages
145
Location
Cornwall
  • May 22, 2016
  • #2

this video might help

Kent

Member
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9,988
Location
Bowland, Lanacshire,UK
  • May 22, 2016
  • #3

Did you just weld it without tacking it up along the joint?

I am struggling to understand what is bent and how but figure it's got to be the angle iron? Which you used as a slam plate?

I think you just did a continuous weld one end to the other without tacks? Not surprisingly it pulled into the weld I suppose

Cut it off sand it smooth and when you for it again you should just put a few stitches on both sides alternating after you tack it both
sides

Slam plates are normally done in flat bar - again alternate stitched ( chain stitch) is what it's called

tinman123

Putting the Extra into ordinary.
Messages
1,068
Location
Northern Iron.
  • May 22, 2016
  • #4

i dont think tack id make a big pile of difference as when you weld it after, even in stitches it ill still pull it indeed just tacking it down its lth will start it off nicely.

the only success ive had welding something to the side of something else is to bend it backwards with clamps and then weld it, when you relaese the clamps if youve guessed it right it will end up straight.

im sure there is a formula for it somewhere probably but seeing since i didnt do that course i just guesstimate it.

Kent

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Location
Bowland, Lanacshire,UK
  • May 23, 2016
  • #5

I don't really think anything because I do this very regular and was taught how as a teenager 30 years or so ago

You must tack both sides and chain stiching will even out the pull and still give all the strength you ever need and more

I am struggling to describe chain stitching though all the other pro welders should know what I mean so I will draw it shortly

Kent

Member
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9,988
Location
Bowland, Lanacshire,UK
  • May 23, 2016
  • #6

Here fag packet plans. Welding distortion is created by heat and the pull is towards the location the heat is applied and the direction of travel
Chain stiching as shown limits heat input and for every pull there is another to counter it
Order of welds applied also helps - don't just stich one side!
Tacks work as a series of clamps but can also mark the start stop points desired

metal bowed after welding (5)

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paul taylor

New Member
Messages
4
Location
Raunds, uk
  • May 23, 2016
  • #7

Thanks guys. Kent, yes the angle iron was welded continuously on 1 side without tacking/stitching the other side. It is not just the angle that has distorted, it has pulled the box section as well. I am not sure whether to stitch the other side to pull it back or cut it off & start again. If I do cut it off, do you think it might return to it's original state?

Paul

Kent

Member
Messages
9,988
Location
Bowland, Lanacshire,UK
  • May 23, 2016
  • #8

metal bowed after welding (7)

No its junk. Why are you using angle as a slam plate anyway. Flat bar directly onto the outer face
This is one I fitted last week see the slam plates

  • DSC_1018.JPG

    262.7 KB· Views: 85

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paul taylor

New Member
Messages
4
Location
Raunds, uk
  • May 23, 2016
  • #9

I used angle on the beam above the gates, this was a left over.

tinman123

Putting the Extra into ordinary.
Messages
1,068
Location
Northern Iron.
  • May 23, 2016
  • #10

Kent said:

I don't really think anything because I do this very regular and was taught how as a teenager 30 years or so ago

You must tack both sides and chain stiching will even out the pull and still give all the strength you ever need and more

I am struggling to describe chain stitching though all the other pro welders should know what I mean so I will draw it shortly

i know what the chain stitching is you describe and in your pic there its about the only way it can be done.
but pauls problem is its actually pulled the box into a curve where as yours is more keeping the welded piece plumb with the box and not pulling it to one side but id be shocked if it actually leaves the box straight after you have welded a flat on one side of it, there will still be a slight curve altho the way you have it drawn will reduce it somewhat.
in your picture of the gate with the slam plate welded flat to the box there wont be as much of a pull.

Welderpaul

Member

Staff member

Messages
14,548
Location
UK
  • May 23, 2016
  • #11

tinman123 said:

i know what the chain stitching is you describe and in your pic there its about the only way it can be done.
but pauls problem is its actually pulled the box into a curve where as yours is more keeping the welded piece plumb with the box and not pulling it to one side but id be shocked if it actually leaves the box straight after you have welded a flat on one side of it, there will still be a slight curve altho the way you have it drawn will reduce it somewhat.
in your picture of the gate with the slam plate welded flat to the box there wont be as much of a pull.

I think where Kent is coming from is stitch welding to reduce the amount of weld (Rather than welding the slam plate/angle all the way down) to stop it bananaring.

tinman123

Putting the Extra into ordinary.
Messages
1,068
Location
Northern Iron.
  • May 23, 2016
  • #12

Welderpaul said:

I think where Kent is coming from is stitch welding to reduce the amount of weld (Rather than welding the slam plate/angle all the way down) to stop it bananaring.

i get his point, but as im sure you know too that when you weld a plate to something like that it will still pull.
welding the angle the whole way down one side will pull the box as it has, stitching it will reduce it immensely but it will still pull somewhat is what im geting at.
eliminating the pull altogether is the holy grail, the thing we all aim for.

blenkie1

Member
Messages
1,006
  • May 23, 2016
  • #13

Welderpaul said:

I think where Kent is coming from is stitch welding to reduce the amount of weld (Rather than welding the slam plate/angle all the way down) to stop it bananaring.[/QUOTE

Did you not start a thread about trying to control distortion? Trying to find it

Kent

Member
Messages
9,988
Location
Bowland, Lanacshire,UK
  • May 23, 2016
  • #14

A lot of what I do has been taught to me years ago. Generally you get a feel for what you can and can't get away with
It might be a holy grail but with the right ways it rarely becomes an issue to produce most things to Tollerance
If however you have never been taught / shown the temptation is always to put too much weld in too soon - skipping all the measuring tacking, sorting the places to weld and order

Kent

Member
Messages
9,988
Location
Bowland, Lanacshire,UK
  • May 23, 2016
  • #15

paul taylor said:

I used angle on the beam above the gates, this was a left over.

Yeah, I am confused as regards the design without a plan. Drawing or photo

blenkie1

Member
Messages
1,006
  • May 23, 2016
  • #16

http://www.mig-welding.co.uk/forum/threads/controlling-distortion-during-welding.61459/#post-769780

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paul taylor

New Member
Messages
4
Location
Raunds, uk
  • May 24, 2016
  • #17

Thanks for your help

Paul

D

Dale allison

New Member
Messages
29
Location
Lancashire
  • Jun 5, 2016
  • #18

paul taylor said:

Hi All. I have made a pair of driveway gates from 60x30x3mm box mild steel. I have welded a 30x30x3mm angle iron to 1 of the uprights to act as a stop, I have only welded 1 side along it's edge as I thought this would be sufficent, but it has pulled the steel from straight by about 10mm over 1.8m in length. If I was to weld the other edge, will it pull it back straight or am I better off cutting the angle off & start again( (I guess by just removing the angle iron it won't straighten itself?)

Thanks in advance for all replies.

Paul.

Hi Paul, when you hear steel up it shrinks when cooling, the best thing to do would be to start again and stitch weld in smaller runs, 20-30mm every 50-100mm apart should 've sufficient for light weight projects, if you are looking for something stronger, I'm guessing not otherwise you would use bigger wall steel and retain the heat, stitches of 50mm spaced 100 apart would be ok, also consider using a heat sink

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metal bowed after welding (2025)

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