I am told radiographic and ultrasonic won’t work on large fillet welds

The Question?

I am told radiographic and ultrasonic won’t work on large fillet welds

I'm calling about the possibility of NDT of fillet (6mm) welded stainless welds. I’ve been told that radiographic and ultrasonic won’t work, and that I should do Dye pen, but I’m unhappy at a surface inspection only. Do you think you can get achieve a sub-surface inspection of a fillet weld? I assume NDT can be done in shop. I can’t access an actual bracket at the moment.
There are various bracket morphologies, but they are all basically are all 316 stainless RHS or CHS lengths, filllet welded onto a flat SS base plate.

The Answer,

My belief is NDT can be performed on almost everything. We only need to be aware of test restrictions to obtain fruitful results by applying appropriate technique and spending adequate time and money.
In your case a fillet weld can be tested using radiography as well as ultrasonic.
Ultrasonic test will be time consuming and thus expensive as compared to Radiography. Ultrasonic test will also have more restrictions as comparedto radiography.
Considering the size as 6mm fillet weld, I believe that Radiography can be performed in a non-conventional way.
We will have to radiograph the fillet weld 2-3 different directions at 10degrees from the plate faces.
This technique will reveal most of the discontinuities within the weld and gross discontinuities at the fusion face and weld root.
This technique will not reveal lack of fusion along the fusion faces.


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