NDT of Existing Framing 2

[dlew]

I have to come with a plan to investigate the capacity of an existing welded steel pipe framing. The structural framing is exposed in a marine environment, and have spots that are starting to rust and pit.
My main concern are the welded connections (pipe-to-pipe, and pipe-to-gusset plates). We are planning to NDT all the welds that show signs of corrosion, and my question is: What type of NDT should I use, and why?

Magnetic particle and colorant dying would test only the top 1/4" or so of the weld.
Ultrasonic and X-ray testing could be difficult in some places because of the framing geometry.

TIA

AEF

 

[evelrod]

Magnaflux and Dyecheck will expose most of the pre-existing flaws in the welds. Most cracks show through to the surface no matter where they are propagated. These two methods are cheap and easy to use but will not show interior or root flaws. For inclusions your stuck with X-ray (very expensive and difficult in the field) and UT. I have used UT in the field many times with very good rate of coverage. Those few welds that are difficult to get to are Dyechecked. ANY problems or doubts or failures in a welded joint, and they should be cut out and rewelded to specs by certified (and qualified) welders. It's cheap insurance! We usually only used X-ray on critical components (high pressure piping, nuclear facilities, etc., that sort of thing).
Always use proper personal protective gear and safe, approved working techniques.


Good luck and work safely.

Rod

 

[pipewelder1999]

If the piping frame is make up of T, K or y connections. Radiography would be difficcult to interpret. You would also need acceptance criteria and a code/specification for the work.

UT can detect and measure corrosion. RT can show the extent of pitting. Sometimes a combination of methods is useful.

 

[WKTaylor]

dlew...

Recommend You submit this thread in the forum for NDT:

QC, Inspection & Testing engineering Forum forum286

Regards, Wil Taylor

 

[dlew]

Evelrod, Pipewelder1999 and Wktaylor,

Thanks for your responses. They were very helpful.

I am considering ultrasonic testing for accessible places, and dye-pen testing in places where ultrasonic could not be used.

Most of the T and K connections in the piping frame are Ok. The pipe-to-gusset plate connections are the ones that show more signs of corrosion.

Thanks again
AEF