Can you use Magnetic Particle testing to check for depth of penetration? The reason I am asking is we have a customer who is useing it this way on a T joint fillet weld that has no beveling and is not 100% penetration. it is a 1/4 inch fillet weld on a .625 thick A36 base metal. I think he is picking up the joint line because there is not 100% penetration.
I wouldn't use MT. A simple mock up and cut and etch will show exactly the amount of penetration you have.
edit: I should have stated that I wouldn't use MT to check depth of penetration. MT is a good tool to have for fillet welds, but checking depth of pen requires something that can see further below the surface and is repeatable.
Is this Inspector Certified to do MT or is this done By Moe Larry and curly inspections? Is the fillet from 1 side. If it is not a full pen weld and you are using mt on the backside of course you will get and indication (duh). If you are lucky you might get a subsurface indication, BUT ITS NOT GOING TO TELL YOU THE DEPTH OF ANYTHING.
To answer your question... No, MT is not for depth of penetration. Having said that, MT can pick up near surface discontinuities. Lack of root fusion on a 1/4" fillet may yield such an indication if the problem is severe enough. However joint geometry may also yield a non-relevant indication at this location (depending on leg spacing...). If the technician is a properly trained Level II tech they should be able to tell the difference.
If there are several of these that the technician has rejected then the question can easily be answered by spot grinding (or carefully gouging) to verify one of the locations. -Bert
I wouldn't use MT. A simple mock up and cut and etch will show exactly the amount of penetration you have.
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