Leak of Stainless steel plug, Material defect?? 2

[MATEGRITY2009]

Hello everyone,

Problem: The new plug of the air cooler heat exchanger made from stainless steel leaked during the leak test. The plug was new and never used. The defective plug was sent to be tested using PT and PAUT and it found the defect at the center and along the entire length of the plug (that's why it leaked during the leak test). I'm confident that this defect is not due to the machine processing used to create the plug.

The plug was sent back to the supplier for the RCA but finally, they didn't respond to the inquiries anymore. So, I'm here to get your thoughts on the possible root cause of the plug defect. Is it an inherent discontinuity or defect from the original melting and solidification of the metal?

Thanks for any help.

 

[EdStainless]

This is made from bar that had very low hot reduction when it was rolled.
This left shrinkage defects (pipe) down the centerline.
I have seen this with plugs, machined elbows, and valve bodies.
This is why expensive fittings are made from extruded or forged stock.
They don't leak.

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P.E. Metallurgy, consulting work welcomed

 

[MJCronin]

In what country was the plug manufactured ?

What is the ASTM/ASME material standard that the plug was supposed to be manufactured to ?

MJCronin
Sr. Process Engineer

 

[MATEGRITY2009]

In what country was the plug manufactured ?

The material supplier is in the USA.

What is the ASTM/ASME material standard that the plug was supposed to be manufactured to ?

Material spec. in PO is SA-479 316L

 

[EdStainless]

So not ordered to a fitting spec?
Can you see the porosity using penetrant? (liquid fluorescent maybe)
What did the supplier say? The parts are obviously defective.

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P.E. Metallurgy, consulting work welcomed