welding joint coeffient

petty · **Posted:** Sat Jun 05, 2010 8:03 am

Dear all
for example, a vessel mark "RT3" ,head is seamless ,circle welding joint inspect per. Uw-11(b),not according to uw-11(a)5.
to calc. the thinkness of head,we must use a welding joint coeffiect "0.85"
But why to clac. seamless nozzle on shell Per UG45(a),we can use joint coeffiect "1"
why?
by the way,I am in chinese.My English is very poor,Do U understand what my expression?

zoecool · **Joined:** Mon Dec 22, 2008 10:23 am **Posts:** 7

Dear petty: please found FIG.L-1.4-2

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

petty wrote:

Dear all
for example, a vessel mark "RT3" ,head is seamless ,circle welding joint inspect per. Uw-11(b),not according to uw-11(a)5.
to calc. the thinkness of head,we must use a welding joint coeffiect "0.85"
But why to clac. seamless nozzle on shell Per UG45(a),we can use joint coeffiect "1"
why?
by the way,I am in chinese.My English is very poor,Do U understand what my expression?

I understand you mean that the extra RT spot on circ.weld connecting smls head to smls shell per UW-11(a)(5)(b) was not performed then E=0.85.
What I do not understand is your concern about UG-45(a). It is a totally different problem.
Mauro

Eric.chen · **Joined:** Mon Sep 06, 2010 5:43 am **Posts:** 6

Hi,petty
i am designing one vessel, during the calculation, i have the same question. I use Pvelite to computer the design. there are two different parameters as follow,
Efficiency, Longitudinal Seam 1.
Efficiency, Circumferential Seam 0.85
we choose the first one to be 1, since the nozzle pipe is seamless, without longitudinal seam. so we can think E=1.
for the second, we should choose per UW-11 b.

Eric

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

Eric.chen wrote:

Hi,petty
i am designing one vessel, during the calculation, i have the same question. I use Pvelite to computer the design. there are two different parameters as follow,
Efficiency, Longitudinal Seam 1.
Efficiency, Circumferential Seam 0.85
we choose the first one to be 1, since the nozzle pipe is seamless, without longitudinal seam. so we can think E=1.
for the second, we should choose per UW-11 b.

Eric

No Sir.
To use E=1 for seamless pipe shell or seamless head you have to comply with UW-11 (a)(5)(b), i.e. one additional spot to the circ.weld joining shell to head. Read UW-12(d) and UW-11 (a)(5)(b) -last three lines.
Mauro

Eric.chen · **Joined:** Mon Sep 06, 2010 5:43 am **Posts:** 6

Gonzaga wrote:

Eric.chen wrote:

Hi,petty
i am designing one vessel, during the calculation, i have the same question. I use Pvelite to computer the design. there are two different parameters as follow,
Efficiency, Longitudinal Seam 1.
Efficiency, Circumferential Seam 0.85
we choose the first one to be 1, since the nozzle pipe is seamless, without longitudinal seam. so we can think E=1.
for the second, we should choose per UW-11 b.

Eric

No Sir.
To use E=1 for seamless pipe shell or seamless head you have to comply with UW-11 (a)(5)(b), i.e. one additional spot to the circ.weld joining shell to head. Read UW-12(d) and UW-11 (a)(5)(b) -last three lines.
Mauro

Dear Mauro,
Yes, i agree, Maybe i have not express my point of view clearly, the two parameters are for nozzle calculation. i try to explain why we can choose E=1 during the seamless nozzle calculation. I'd like your opinion about it.
Eric

Jackal · **Posted:** Mon Sep 13, 2010 7:10 pm

UW-11(a)(5)(b) is ASME's way of providing a means to ensure confidence in the quality of connecting butt welds (Category B or C) attaching vessel shells/heads/communicating chambers.

The Spot RT requirement of UW-11(a)(5)(b) can be classified as a "quality shot" for confidence when determining the joint efficiency of the intersecting (imaginary or real) butt welded longitudinal joint.

It does not come into play when calculating reinforcement of nozzles per UG-37 or UG-45, just because. No explanation needed.

Gonzaga · **Joined:** Sat Dec 15, 2001 1:00 am **Posts:** 657

OK E=1 in circ.stress calculation for nozzle seamless pipe.
MG

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