Urgent TIP on torispherical head to be transported into two halves

[fedeghi]

I have a question that's puzzling me this evening, and any hint would be really appreciated.

I am dealing with a torispherical head that has to be delivered into two halves, for transport issues.
In attachment you can see the geometry, and consider that it will be manufactured from plate, A516 gr60N.

The idea is to cut it along its diameter AFTER forming.
Consider that this head will not be welded on a real ASME "pressure equipment" (design pressure is 0.6 barg, Temp is 350°C).

I was wandering about what may happen when we cut a head like this after formation. Should we expect to observe free deformation due to some stress concentration that the head has suffered during forming?
Will the two halves edges not correspond when they will have to be re-welded on site?

Honestly, I can't predict what's going to happen.
Any help will be highly appreciated.

Thanks!

 

[vesselfab]

165" diameter is not that large....but maybe on other parts of the world.

you can make a cradle to mount the head standing on edge but leaning to one side to keep the height and width down

that's what i would do to keep from cutting the head and trying to reweld it.

 

[fedeghi]

I'm afraid that we will have to proceed with cutting anyway.

But what about the deformation after cutting?

 

[SnTMan]

fedeghi, if distortion is a big concern, you could weld fixturing plates to the head along the cut line before cutting.

I doubt anybody can say for sure what it will do when you cut it.

Regards,

Mike

 

[boilerone]

You can easily weld temporary bracing steels inside the two halves (before cutting) so as to keep the dimensions and cut them off after re-welding.

 

[GenB]

just cut the darn thing, fixture it to weld and heat treat it to to take the stress
and hope for the best . you are lucky
for pressure you would have to RT

 

[SnTMan]

boilerone, thank you, temporary bracing was the term I was groping for (and missed)

 

[Weldmedic]

Heads like this are usually fabricated in halves, not totally welded. During the forming process the individual plate section geometry is usually verified with sweeps and templates. During fitup and assembly, bracing is used to maintain configuration for fabrication, inspection and shipping.It would be difficult to predict where deformation(if any) would occur after a cut. If you absolutely have to, prior to cutting, brace adjacent to the cut line and radially to the center and at each weld seam on each half of the head. Reassemble fit and weld out diameter and circumference prior to removing the bracing. Assure that whatever bracing you use is robust.

 

[vesselfab]

Our large heads are completely welded in the flat.
then Radiographed and MT.

at this point they are normalized.

then formed in one piece.

It's been a while since i have seen a head fabricated in sections and then welded,,except for extremely large heads