weld buil up on pressure vessel nozzle hole- legal? 2

[shervin73]

T here is nothing mentioned in ASME VIII about the subject. Tan somebody help me to know how much is allowed?
The operator made the nozzle hole in wrong direction so it must be modified to its right.
Thickness of the vessel is 100mm and modifying the hole needs about 100mm build up!!!
I know it's not logical but we couldn't find any reference.

 

[gr2vessels]

There is nothing mentioned in ASME VIII about your subject because it is not against the Code requirements. Provided you can prove with specific tests and approved welding procedure, the quality of material deposited, it should be equal to the plate material you are using to manufacture the vessel. The thickness is irrelevant. Remember, there is plate material with weld deposited cladding, which can be counted to the strength of the plate in certain conditions. Your weld deposit is not different from the cladding material.
Cheers,
gr2vessels

 

[metengr]

You can use a full penetration flush patch plate versus trying to fill an opening with weld metal.

 

[shervin73]

Thank u gr2 vessels and metengr,
we thought about both patching and buttering but we were not sure that buttering (or build up) is permissible for 100mm. it is equal to the plate thickness.

I believe that patching is more reliable than 100mm or even more weld build up. our contractor are insisting to build up instead of patching.
for your information, the plate is not weld overlay (explosion cladded type)and clad material is not considered to designing the required strength.

any other comment would be appreciated.

 

[weldtek]

Certainly either weld buildup or a full pen patch of matching base metal would work. If you're the owner what's your preference? Normally this kind of rework would be handled under an NCR and any proposals run by the owner for approval.
From a practical standpoint, since you're only relocating the opening around 4", in 4" thick material, even using a patch plate will result in pretty much 100% weld metal being used, however, it would be easier to perform RT on the repair area with a patch plate. Keep in mind you don't have to weld the patch around its entire circumference, you just need to weld the area outside the new opening plus an amount sufficient to facilitate welding and NDE.

 

[shervin73]

This is the situation.
black lines shows the present direction (wrong direction) and should be modified to red lines.
so the gray triangle must be weld build up.
Or make the hole larger, and prepare circular patch to close the hole and make the hole in right direction into the patch.

http://files.engineering.com/getfile.aspx

 

[metengr]

If I were the owner, I would tell you I want the flush patch, full penetration weld, NDT and re-drill the nozzle opening.

 

[stanweld]

If you have the original drop from the cut out or drops from other nozzle cut outs into the shell, use it or one of them and repair as indicated by metengr. Of course you may also weld build up; As purchaser. I would require RT of weld build up area prior to remaking the nozzle cut out.

 

[GenB]

If this is a full penetration welded nozzle, for what I see a triangle with original opening of about 2 in around, now one side will have extra 2x2
area triangle, it is not that much fill after all. one side of the triangle will open +2inch.