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Checking for cracks on internal threads

Checking for cracks on internal threads

Checking for cracks on internal threads

I'm looking to inspect some parts for cracks to internal threads.  The parts in question are 15-5PH H1025.  The threads are 1-14-2A x 2" deep. The part is about 2.375" outside diameter by 3" long.  

We called a local Xray house and the tech support person said the wall thickness (approx 0.670") was too heavy and Xray would not work.  He recommended mag particle.  I am skeptical about being able to see cracks at the root of the threads by that technique.

Any ideas would be greatly appreciated.

RE: Checking for cracks on internal threads


I agree with the Xray house that RT would not give you what you want.  I suggest water washable or post emulsifiable PT.  You will want to get a 90 degree head on the water source to clean the root out good and maybe an extension for the developer spray can nozzle.  Other than that, pretty straight forward inspection, view thread roots with dental mirror.


RE: Checking for cracks on internal threads

Hello RMS1956

The advise of magnetic particle is good, only use a coil and fluoressent fluid.
PT is also possible, I would do that also fluoressent.
For viewing the mirror is ok, but a small endoscope can be used too.



RE: Checking for cracks on internal threads

You can also use ultrasonic testing to verify any visual thread root indications from wet fluorescent MT. We have used this many times with great success on large steam turbine casing bolts.

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