Figure 11-6.--Principles of shadow formation.
sources varied 90° from each other. Unfortunately,
are less dense than the surrounding steel. Therefore,
many parts do not lend themselves to this procedure.
they absorb a smaller portion of the beam passing
through the metal, and they show up on the radiograph
as darkened areas. The characteristics of the more
common defects revealed by a radiograph are briefly
described as follows:
The defects most frequently detected in steel welds
Surface roughness appears as irregular light
porosity, cracks, and incomplete fusion. Sand
and dark areas having contours identical to the
inclusions, porosity, shrinkages, and hot tears are some
of the defects revealed in steel castings. These defects