Wednesday, November 4, 2015

Radiograph and IP (off The Facebook)

James H
I recently had a friends weld get rejected by xray for a concave bead.  Repaired it, reshot it, and it came back rejected for IP.  Two times in this last year I've heard this. Both times, same example. Is it just a bad xray tech or is it a change in the rules today?

Paul W Cameron - CWI
A friend eh?
Let me preface this by saying, "I'm no RT Guy." but, a concave bead in a radiograph could easily mask Incomplete Joint Penetration (IP).
A concave bead will appear darker (because it's thinner) than the base material around it when viewed in a radiograph. Once that concave bead is repaired (adding more weld [making it thicker then base material]) the area that was once dark is now light and any IP would be clearly visible.

Great Question!


Unknown said...

I got asked why I didn't have the RT TECH shoot tracers when the original shots failed for IP and LOF. I tried explaining to the person that per UW-52 it doesn't mention the term tracers, just that when one shot fails for spot radiography then you need to shoot two more spot shots somewhere within that same weld segment by the same welder, not necessarily on each side of the original shot. My question is, what is the proper term for tracer and why do so many people misunderstand it. Also, just to make sure, is it ok or not ok to not shoot those other two shots the same day?

Paul W Cameron - AWS/CWI said...

In my original post I noted that I'm no RT Guy. When I read your comment I have no idea what "UW-52" and "Tracers" mean. You probably need to ask an RT Guy :-)

DPeter67 said...
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DPeter67 said...

UW-52 is from the ASME Boiler and Pressure Vessel Code.
UW-52 covers SPOT radiography uf a "unit of weld made by "A WELDER". The code requires 2 additional shots (radiographs) also commonly called tracers...from THAT UNIT OF WELD. UW-52 leaves it up to the inspector to choose the locations of the additional shots of THAT WELD made by THAT WELDER.