Ground flushed longitudinal welds overlapped by external reinf. rings 1

[DORU]

I have the following situation:
We have ordered a vessel to an italian manufacturer which during the manufacturing DID NOT GROUND FLUSHED the longitudinal welds before welding over them the reinforcing rings and some plates for platforms fixing.
I told them that this is not acceptable so they proposed me
to accept the situation considering that "we have done on internal side, after flush-grinding of barrel's longitudinal welding, Ultrasonic Test the interested area and no defects have been found".
Please I need a very strong support (something from ASME 8 or 9) in order to accept or reject their proposal. Any advise is welcome.
Thank you very much.

 

[johnnymist2003]

Hi Doru,

look specifically at ASME VIII, Div 1 clause UG-82 - grinding flush is required.

John

 

[deanc]

Hummm-It could be argued these are non-pressure parts. In which case UG-82(b) would apply. See Interps. VIII-1-83-297,
VIII-1-89-113,VIII-1-89-174.
What does the AI say?

 

[WBH]

I concur that these are non-pressure parts per UG-80(b) in which the long. weld could be ground flush or the attachment coped to clear the long. seam. Additionally there is not an exemption for NDE performed on the plate joint. The reason for these requirements (grinding weld or coping attachment)is to prevent any undue stress from method of attachment, UG-82 ensures the external attachments are formed to the vessel section it will be attached to.

WBH

 

[bmoorthy]

Option 1: This is a long shot but still you may try. To convince the AI if he rejects your idea to leave it as it is , is to offer a one to one mock up and offer some physical testing or fatigue testing.

Second option: Cut (By grinding) the central portion of the covering pad plate, leaving 10 to 15 mm on all the sides on the shell itself and then provide a box type cleat back plate and weld it so that the arc does not strike the vessel wall. Leave a Notched portion the web plate near the area where the longseam coincides so that there is no weld over the weld. Here you do not have to flush grind since the top plate clears the shell.

Third option: Split the pad plate so that long seam is uncovered, this may be sufficient for external piping or platform cleat (under normal circumstances for an external support cleat, unless it is a reboiler support local load analysis is not required). Your Ai may not object to this.

Good Luck

 

[vak]

bmoorthy
Option 3 apperars to be OK. Other options are a bit too radical.