nozzle weld from the inside of the vessel wall

[Spoonful]

Hi All,

I got a nozzle need to be attached to a dish end, due to space limitation on the outside of the dish end, it is difficult to weld this nozzle on the outside of the dish end. the solution is have the nozzle protruding a little further into the dish end, and do a full penetration weld from the inside, then add a fillet weld on the top, just like how it is normally done from the outside. and all this is done before weld the dish end on to the vessel barrel.

I can't see why not this can't be done,it is equivalent to a UW-16.1 type C attachment weld, but only welded from inside of the vessel.

Any comment?

Regards

Spoonful

 

[gr2vessels]

If you meant UW-16.1 type (d), you are correct (the inside protrusion is optional as per UW-16.1(l) for partial penetration, if applicable).
This is full pen welded from inside and has added a small fillet (refer definition t_c) on the outside of the shell.
Cheers,
gr2vessels

 

[Spoonful]

Hi gr2vessel,

The problem is that, it is not possible to reach the nozzle from outside, otherwise we would just use UW 16.1 type C weld. So the small fillet weld for type D is not achievable. The question is use exactly as type C but flip it weld direction. Any comment on this?

Thanks

Spoonful

 

[chicopee]

Is that fillet weld to increase the area of compensation within the limits of reinforcement?

 

[gr2vessels]

No, the fillet weld is intended to remove the stress concentration, emulating a 'radius' weld. Obviously, this time we're looking desperately to make good a bad design, stretching the limits of the code. Again, the compromise is sought from the code, not from a correct engineering. I would spend some money removing the flange in order to make room to put the fillet weld on the right place. But again, that's me and I cannot suggest ignoring the fillet weld which is very important, perhaps the thing to save a couple of lives if the nozzle would fail because that missing miserable fillet weld.
For some reasons, I could not open this time the attachment to sent, perhaps a glitch on my PC. However, the radius could be emulated by a good welder, increasing the weld gap and increasing the amperage to force a bulge of the root weld from inside towards outside. Remember, you have to cheat the welding procedure to save face.
You are the judge if it's worth the risk.
Best of luck,
gr2vessels

 

[Spoonful]

Hi gr2vessel,

Thanks for the advise, after spoken with our production manager, he agrees welding only from inside is not a good idea, won't achieve a good result at the back of the weld, and no good for any testing. Best to do is spending extra time on removing the obstruction , then put them back afterwards.

Thanks

 

[gr2vessels]

Good man,
Cheers,
gr2vessels