Subsurface Corrosion

 

MOI 308/7 image of a small corrosion pit (the dark area in the center of the picture).  Corrosion is irregular in shape and can be most easily identified by moving the imager across the area being inspected.

 

Corrosion is seen as irregular shadow shapes moving with the imager.

 

 

 

Spotwelds

 

The MOI is also being used by the military to detect defective spotwelds.  Good spotwelds show as very faint rivet like images.  A broken spotweld image shows clearly.  A Technical Order exists for spotweld inspection of the KC-135 aircraft.

 

 

 

 

Surface Cracks

 

MOI 308/7 image of a surface crack protruding from both sides of the circular rivet site.  The small format imager examines one rivet site at a time.  The frequency for this image was 200 kHz.