Remove of Pressure Containing Part

[IdanPV]

Hello All,

During a fabrication of a pressure vessel it was discovered that one of the nozzles were welded in the wrong location.
It was suggested to remove, by cutting, the nozzle and to close the hole by welding - using weld metal buildup or using small piece of steel and weld it.
Design code is ASME VIII-1.
Hole diameter=~30mm, Plate thickness=6mm no RT or UT is required.

Please advise,
Thanks.

 

[FMJalink]

Hi IdanPV,

Easiest way is just leave it and blind it off. Depends of course on whether the nozzle is acceptable for the process in the vessel and for the outside surroundings.

When the nozzle is set-on clean removal is relatively simple. Normally a larger hole is made in order to remove the heat effected zone and maybe the locally slightly damaged vessel wall.

When the nozzle is set-in the need for larger hole is larger in order to remove the nozzle material and the heat affected zone. With a set-in nozzle more heat will have entered in the vessel wall then with a set-on nozzle.

I am not that sure whether this can be done without NDE and retest. Depends on the applicable Code and legislation.

Good luck.

 

[IdanPV]

Hi FMJalink,

Thanks for you answer.

Some more information that may help:
This is a set-in nozzle.

There is no option to leave this nozzle in place, the only options are disqualify and destroy the vessel, Or remove the nozzle and fill the remaining hole with buildup weld or small piece of steel.

The question is: are there any Code limitation regarding this issue?
Are there any NDE requirements?

Thanks.

 

[SnTMan]

IdanPV, this kind of thing happens all the time. Weld a plug in the hole, grind flush, MT / PT, RT the weld, local PWHT if the material requires it, go on down the road. Like it never happened.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[IdanPV]

SnTMan & FMJalink

Thanks for your answers,
What a helpful forum this is, thanks!

 

[LittleInch]

Just make sure it's noted in the original text and fabrication so it's not classified as a "repair"

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[IdanPV]

LittleInch,

Thank you.
What does it exactly mean? it is a "repair" but it made during fabrication. How can I avoid it to be classified as "repair"?

Thanks again guys, appreciate it.

 

[weldstan]

If the repair is made after hydrotest and U-stamping, the rules of the NBIC are required to be met in most Jurisdictions in the USA and would be classified as a Repair thereunder. If repairs are done prior to the above, they are made under ASME VIII, same as vessel and no special reporting is required.

If the oroginal hole was trepanned out, try to use the original cutout for the repair.

 

[IdanPV]

Understood!
I forgot to mention that the repair is made prior to the hydrotest and the U-stamping of the vessel.

Thanks again guys.

 

[SnTMan]

IdanPV, you may want to get buy-in from the client, depending on contract requirements and relationships among the parties.

Best of luck

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[r6155]

Where was the manufacturer's inspector?

Regards

 

Like it never happened.

That something happened at the repaired spot will be visible from across the street, so not quite.

(What happens in the weld shop doesn't stay in the etc.)

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

 

[r6155]

This repair must be indicated in the "as built" drawing.

Regards

 

[SnTMan]

Well, functionally anyway

EDIT: and for most ordinary materials.

The problem with sloppy work is that the supply FAR EXCEEDS the demand