Welding - repairs to repairs

[dbday]

Hi,

I have a carbon steel presure vessel with a 6"NB XXS nozzzle which is terminated in a pipe cap.
X-ray of the nozzle to pipecap weld found a defect in the weld which has been repaired.
However, x-ray of the repair has shown a defect in the repaired weld (albeit not as bad as the original defect).

Am I ok to repair the repair ?

Are there any restrictions concerning repairs of repairs, can I go on as many times as is needed until they get it right ?

Advice will be appreciated.

 

[phighfill]

You can only repair 3 times, other than that, go for it. After 3 repairs then the weld is to be completely removed and rewelded.

 

[LCeballos]

Search in ASME Section VIII div 1, paragraphs: UW-38, UW-51.

Regards,

Luis C.

 

[metengr]

After 3 repairs??????????? Where did this advice come from? You can weld repair as many times as needed provided total PWHT time is factored into the WPS used for the repair, if PWHT is applicable. If not, there is no limit on weld repairs provided NDT is performed before and after repairs.

 

[bernoullies123]

Generally, most client specifications will not allow any repair without a qualified repair weld procedure, and they generally restrict the number of repairs to those number of repair cycles qualified.

Back to the ASME codes, and others for that matter, as metengr noted, the number of PWHT cycles is a essential variable and will need to be qualified. I have used and seen many client specification that state that WPS's need to be qualified with a minimum of 3 PWHT cycles.

 

[dbday]

Thanks guys, I think that tells me what to do.
Cheers