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1543 views
01:19 May-08-2005
Jim Jordan
Inconel/carbon steel welds-"false positive" indications with RT and UT

We produce an Inconel 625 butter weld to 8630 carbon steel. RT and UT examinations both detect a linear indication which appears to be non-fusion. Subsequent destructive examination shows a good weld with 100% fusion. Has anyone has similar experience?



    
 
03:17 May-09-2005

Frits Dijkstra, RTD bv Rotterdam, NL

R & D
Applus RTD Technological Center,
Netherlands,
Joined Jan 2004
6
Re: Inconel/carbon steel welds-"false positive" indications with RT and UT Dear Jim,

The false indications you noticed with RT can be caused by diffraction phenomena, which are also known to be possible in the heat affected zones of welds like austenitic / duplex / 9% Nickel. Such indications can indeed appear as linear indications an can lead to misinterpretations (false calls).

Also UT can give false indications in this case, caused by the interfaces between the different materials in the weld. The only way to avoid this might be the use of specialized UT techniques using refracted longitudinal waves. Test samples with artifial defects such as holes and notches will be required to optimize such an approach for the welds you are looking at. We will be happy to assist.

----------- Start Original Message -----------
: We produce an Inconel 625 butter weld to 8630 carbon steel. RT and UT examinations both detect a linear indication which appears to be non-fusion. Subsequent destructive examination shows a good weld with 100% fusion. Has anyone has similar experience?
------------ End Original Message ------------





    
 
23:01 May-05-2014

massimo carminati

Consultant, AUT specialist
IMG Ultrasuoni Srl,
Italy,
Joined Apr 2007
691
Re: Inconel/carbon steel welds-"false positive" indications with RT and UT In Reply to Jim Jordan at 01:19 May-08-2005 (Opening).

I experimented the same matter and the only way to ensure these were false calls has been to machine flush the weld root protrusionand inspect with both creeping wave and PA longitudinal wave from both sides of the weld and only from inside, because from outside we also had falsa calls with UT. Be careful, just grinding the weld root protrusion may not be enough.


    
 


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