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Main flange to shell - Full RT 3

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ElCidCampeador

Mechanical
May 14, 2015
274
Good day,

first of all sorry if I ask this question another time (I think that this theme has already discussed many times in this forum).

Considering a pressure vessel designed according to ASME VIII Div.1, where the main flange is directly welded to the shell with a joint type 1, with E=1.

This joint is a category C, right?

If Full RX is required, do I have to do RX on this weld? According to what point of ASME? I'm trying to understand UW-11...thank you for your help and patience
 
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ElCidCampeador, Cat C is correct.

It look to me like the least you would have to do is spot the round seam per UW-11(a)(5)(b). If any of the service or thickness restrictions of UW-11(a)(1) thru (4) apply I'd say you need to full RT that seam.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand
 
SnTMan said:
If any of the service or thickness restrictions of UW-11(a)(1) thru (4) apply

Nope

SnTMan said:
It look to me like the least you would have to do is spot the round seam per UW-11(a)(5)(b)

Even if shell is seamless?
 
I'd say yes. Very common practice in the S&T world.

The problem with sloppy work is that the supply FAR EXCEEDS the demand
 
Marty, yes, excellent :)

The problem with sloppy work is that the supply FAR EXCEEDS the demand
 
Thank you guys.

What sounds odd to me is that this kind of weld is required "only" RX spot by ASME (in normal service and low thickness) when for other circonferential joints (e.g. shell-to-head, even in the same vessel) is required full.
I mean, in my (short) experience all welds between main flange and shell have been taken "full" regardless of code and treated as Cat. B welds by common practice...is there a "technical" reason why ASME requires only "spot" as minimum?
 
Hmm...my first post was deleted. Any flange to shell/nozzle is considered Cat. C per UW-3.
There are two types of "full radiography"....RT1 and RT2.
RT1 would RT the full length of this weld.
RT2 only requires a spot per UW-11(a)(5)(b).
when for other circumferential joints (e.g. shell-to-head, even in the same vessel) is required full.
This is not correct. Any Cat. B would require the same spot to achieve full radiography (RT-2), per UW-11(a)(5)(b). If the head was hemispherical, then it would require RT of the full length of the weld, as that is a Cat. A weld.
 
See UG-116(e)(1) thru (4) for RT1, RT2, RT3, RT4 requirements.
 
david339933 said:
See UG-116(e)(1) thru (4) for RT1, RT2, RT3, RT4 requirements.

Still not clear.
UG-116(e)(1) for RT1 refers to UW-11(a) in a generic way, but inside this paragraph I don't understand the exact point which requires full RT for Cat.C joint main flange to shell (with no particular limitation of service or material or thickness etc...). Could you please show me?
 
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