Reinforcing pad crosses over the longitudinal seam 1

[rajat84]

Dear All

I am design ASME U stamp vessel.

I wanted if weld on weld is premitted in ASME, i.e. longitudinal seam is run over by reinforcing pad weld.

Ideally I am trying to do 100% radiography before aand aafter weld. I cannot find in ASME code if it is allowed?

Any views greatly appreciated.

 

[doct9960]

See UG-82

 

[gr2vessels]

Also refer to UW-46, with particular reference to the note in the brackets, at the end of the Clause (my copy of ASME VIII Div. 1 is missing Clause UW-15(d)). However, you should do the 100% RT on the long seam, before you cover it with the reo pad, but I would discourage you to cover it in corrosive service or other similar demanding services. There is always a chance to re-design the reo pad for smaller OD and increased thickness, in order to avoid the overlap with the long seam. Or, is there any chance to rotate the long seam to avoid covering it with reo pads?
One more thing, if you must cross the pad's fillet weld over the shell long seam, try to design the pad so the welds crossing angle is as close to 90 deg as possible.
cheers,
gr2vessels

 

[roca]

Note that reducing the reinforcement pad diameter may affect your nozzle load calculations.

The minimum distance between the edge of any attachment weld of a pressure part (nozzle, reinforcing plate) to the edge of a another pressure weld of the vessel shall at least be 50 mm or twice the thickness of the pressure part, whichever is the greater.
If this is not possible the attachment weld should cross the pressure weld completely by a length of at least 50 mm or twice the wall thickness (whichever is the greater) in order to avoid any stress concentration.

Before the attachment weld is made, 100% NDE should be performed in accordance with code requirements (ASME VIII = UW-11) on the pressure weld in the area where the attachment weld will cross.

 

[doct9960]

gr2vessels,

my copy of ASME VIII Div. 1 is missing Clause UW-15(d)

UW-15(d) was redesignated to UG-37(g) in the 2004 Edition, 2005 Addenda; but this was not reflected in the 2007 Edition. You could send a request for revision on UW-46, i.e. change the last sentence in brackets to read as "[For tests on reinforcing plates, see UG-37(g)]"

 

[gr2vessels]

Thanks, I shall do.
cheers,
gr2vessels

 

[rajat84]

Thanks Guys,

I really appreaciate ur help. It helped me to make descicion congfidentalaly.