Liquid Penetrant Sequence 1

[RyderT]

Part # 1 contains an ASME full penetration double sided butt weld that requires final radiography and liquid penetrant NDE.

Part # 2 attaches to Part # 1 with a partial penetration joint and requires final liquid penetrant testing. The partial penetration weld that attaches part # 1 to Part # 2 covers a portion of the full penetration weld.

Can final liquid penetrant testing of part # 1 be performed after the part # 2 is welded to part # 1 per ASME, even though a portion of the full penetration weld is covered by the partial penetration weld?

 

[fegenbush]

RyderT,

My first thought is to say that the NDE of the weld on Part # 1 must be complete before Part # 2 is welded to it. This is because the second weld will obscure the view of the first. Additionally, I do not see how you (or your interpreter) could accurately read a radiograph taken through a full penetration weld and a partial penetration weld. Lastly, if there were a problem to be repaired in the fully radiographed weld, it would be more difficult to do so with another weld on top of it.

My personal preference is to use the liquid penetrant test after the root pass has been applied when looking at the back gouged/ground side of the weld before the final cover pass is added. This ensures 100% penetration of the weld and has spared me from having to have the radiographers in the shop twice.

 

[RyderT]

Thanks for your input. I concur.