Exploded graphite in SG Iron casting

[smurali1]

We have some SG Iron castings. We found exploded graphite formation in some of the castings after machining.
(The confirmation was done by destructive study of one casting)
Are there any NDT method to find out how much depth is exploded graphite?

Thanks

SPM

 

[JoeyV87]

No, the only way to detect nodule form at any depth is to cut and look. Or if you know what's causing it you can cut and get a chemistry (I'm assuming its a chemical impurity).