Controlling distortion during welding

[blenkie1]

This is a part for a car transporter, common design this particular one goes on one of the biggest manufacturers of transporters in the UK

I spent 12 years working on car transporters. They are a nightmare! probably the worst job I've had. We used to make them from scratch when I first went and then we started to just strip the trailers we had and redesigning/modifiying them to what we needed. Because the law changed we could add an extra 400mm into the chassis so that was my main job. Used to take me about 3 weeks to get a trailer, strip everything off, Hydraulics, Rams, Chains, Electrics, and anything else and rebuild it all back up again.

 

[Kent]

How do you ensure the tags remain at 90 to the beam?

A guy I used to work with served his time in the shipyards. He was a burner by trade and one of his jobs was applying heat in the correct place to correct warping caused when welding the plate steel on ships. He freely admitted it was a black art, impossible to teach and only learned through experience.

Flame straightening on hull plates is no great black art I recon most who do it just do what they were shown without ever thinking about the why it worked
Burning generally seems to be something of a disappearing skill in recent times though

 

[AndyStobbs]

O/T, but how much penetration do you get into the channel on a job like this Welder Paul?

 

[Turbo]

Flame straightening on hull plates is no great black art I recon most who do it just do what they were shown without ever thinking about the why it worked
Burning generally seems to be something of a disappearing skill in recent times though

Unfortunately this guy spent too long doing just this job and ended up a one trick pony. He was employed as a fitter with us and was pretty useless at most things. You would thing that he would've picked up welding skills along the way but he couldn't do that either. Most of our work was with stainless steel so his burning skills were rarely needed!

I remember seeing a 6x4 car trailer being built at work. The fitter (a different one) welded all the floor support cross pieces to the lower side rails, all 40mm angle iron. He didn't account for warping & the bottom rails ended up being 25mm out between the end & middle of the rail! I know coz I got the job of fitting the sides and I had to cut a curve in the boards to get them to fit!

That taught me a lesson & if I'm welding in the middle of angle iron I always clamp a piece of 50x50x6 box section to the back to stop the angle 'pulling'.

 

[Kent]

Yes they were one trick ponies I also worked with one
He told me of how he could only work his torch on certain sizes otherwise the union was onto him
It did make them very practiced at that one thing though
To be fair this degree of specialisation can be an issue in all trades welders, machinists etc

 

[Welderpaul]

O/T, but how much penetration do you get into the channel on a job like this Welder Paul?

Enough

We work to certain company standard welding procedures which have been carried out on test pieces using the same grade and thickness (or thicker) steel, same gas, same wire and in the same welding position, then destructively tested. This means we know, using those parameters, that the weld will function correctly.
Welds are visually inspected and that's about it for a job like that.
We UT test a certain percentage of jobs over 25mm thickness.

All welders at our place are BS9606 'coded', so with that in place, the welds should be right.

 

[Welderpaul]

Good information there Paul. What make are the clamps in the picture. Cheers.josh.

Piher clamps. They are a really good bit of kit, must have 30 or so, various lengths. They take some serious abuse, the only thing with them is the rack bar starts to bend backwards but every so often we put them in the press and straighten them.

I can't moan because we are using them far beyond their capacity.

 

[Welderpaul]

Sorry if this is a stupid question but..

if you find by trial and error that 25mm packing obtain s flat result thats good.

If you did the same job without the packing would you see 25mm of bow or something less?

I think something less is probably the answer ?

Pretty much, yes.

 

[The flasher]

Cheers welderpaul.

 

[AndyStobbs]

Enough

We work to certain company standard welding procedures which have been carried out on test pieces using the same grade and thickness (or thicker) steel, same gas, same wire and in the same welding position, then destructively tested. This means we know, using those parameters, that the weld will function correctly.
Welds are visually inspected and that's about it for a job like that.
We UT test a certain percentage of jobs over 25mm thickness.


All welders at our place are BS9606 'coded', so with that in place, the welds should be right.

I wasn't worried that it wasn't up to scratch, just curious. I have a hell of a gut feeling for what will work, when mending things, but less so on welding things.

 

[Rrunnach]

Burning generally seems to be something of a disappearing skill in recent times though

It is still being taught, Kent. I had two groups burning all day yesterday. Use of PUG, free hand and, use of aids.

Paul, not steel, 200x75x6 al/al channel section, which were installed inside Trident subs, very tight tolerance.
Rectangle frames, done same as steel, made up in L's, before putting them together. Offset prior to tig welding, allow to cool, if crept under 90*, then onto a stake to planish wed, till 90* was achieved. then put L's together, same again if diagonal were out. that was one PITA job I will never forget!

 

[Kent]

It is still being taught, Kent. I had two groups burning all day yesterday. Use of PUG, free hand and, use of aids.

Paul, not steel, 200x75x6 al/al channel section, which were installed inside Trident subs, very tight tolerance.
Rectangle frames, done same as steel, made up in L's, before putting them together. Offset prior to tig welding, allow to cool, if crept under 90*, then onto a stake to planish wed, till 90* was achieved. then put L's together, same again if diagonal were out. that was one PITA job I will never forget!

Unfortunately not to the amount of pupils it was and is that not as an add on rather than as an apprenticeship in burning as a stand up trade?
I can burn but not like the specialist trained fully skilled burners I have worked with

 

[Rrunnach]

Unfortunately not to the amount of pupils it was and is that not as an add on rather than as an apprenticeship in burning as a stand up trade?
I can burn but not like the specialist trained fully skilled burners I have worked with

As Bob Dylan sang "the times they are a changing" and have done for a few decades now.

What is being done is not an add on, it is a fundamental unit where burning skills are hopefully learned. A couple of lads are well skilled up, as they back gouge sea fastenings from offshore supply vessels, same for gouging out back of roots.

Other lads, some use it, some will never use it in their current employ, however, if and when they change employer, or go self employed, they will have good practicable and, knowledge skills, probably former and latter a tad rusty.

With CNC O&A, Plasma and, Laser, the stand alone trade as a burner, is dead in the water.