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nde rt1 on boiler shell

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GenB

Mechanical
Oct 24, 2003
1,362
on scotch boilers, we do not weld about 2 in at the edge of the smoke box on the long seam weld joint, the sub-nde x-rayed the complete long seam and reported unwelded part as lack of fussion. The AI now wants me to reweld and re-x-ray the edge . are they in their right mind or not? My understanding is that if the edges are not part of the pressure "drum" or outside of the pressure boundaries, there is no need for nde on that part. Any advise and/or coments thanks, GB
 
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generalblr,
What is your technical justification for not completely welding out the seam and applying required NDE? Unless the portion of the longitudinal seam outside the pressure boundary has been subjected to an engineering evaluation in the design documentation, allowing it to be removed from consideration, I would tend to a more conservative approach and consider the entire seam as being subject to Code rules. My two cents
Regards,
RLS
 
The AI is absolutely correct. The smoke box seam weld must be a full penetration fusion weld. Any lack of fill is considered a stress riser and could result in cracks.
 
Will the stress riser affect the pressure part beyond the tubesheet which is 2 to 4 inches away?.-
The smoke box does not contain any pressure.

We have not problem in compliance and we have to do things right "we like to know who's right" and be happy.

Justification: none, but to keep cyl round we hold it from the edges leaving 1 to 2 inches unexposse to welding, we finish afterwards but it goes to nde before that.- now we have to change and finish it before nde.
thanks for your help, Regards,
GB
 
I would have to defer to PFT-10.

How about using a "run off" tab on each end? Holds your material in place. Allows you to complete the weld on the shell. Cut it off an throw it away when you complete the final weld.
 
I found out that the ASME Code allows the former, it is up to the AI to accept the practice. I have a knowledgeable AI but arguments always come out.

In the end is is right to do it right or well done with "no loose ends"

Is is not a problem to comply, I wanted to find out your opinions.
Thanks to all for the imput, it is important to share information,
GB
 
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