Repeat Hydrotest and Radiography After Weld Grinding? 1

[cb418]

During the hydrotest of several small ASME B31.3 pipe assemblies, a gouge was inadvertently put in the circumferential butt weld. The gouge was removed by grinding (not below the thickness of the adjacent base metal, the weld is still slightly convex) and then was liquid penetrant examined. The weld was 100% radiographed prior to hydrotest. Is there a ASME section, interpretation, code case, etc. that will support not having to repeat the hydrotest and radiography after this repair, which is really just surface finishing; no welding was performed and the full required weld thickness remained. Any assistance would be greatly appreciated, there are a lot of these that got damaged. Thanks.

Chris

 

[metengr]

In my opinion, a re-hydrotest and NDT are not required for a mechanical repair (no welding) based on your stated information.

 

[JR97]

Chris,

ASME B&PV Code Section III NB-6115 allows the lesser of 10% of wall or 3/8 inch to be removed after hydrotest. Assuming your grinding met the above no additional hydrotest is required (if NB is applicable).

Radiography is a volumetric examination. All of the material present was inspected. Therefore, grinding and blending a gouge does not invalidate the inspection; you just know you had good grinding dust! What you did not mention is that final surface inspection (MT or PT) should be performed after grinding on the new final surface.

JR0097

 

[cb418]

JR0097,

Thanks for your very specific answer! I have also found a Section III code case that waives radiography for this situation, so I'm fully covered.