The short wavelengths of radiant energy have become a useful tool for the inspection of die castings. As the rays pass through materials of non-uniform structure containing defects such as voids, porosity, or cracks they are absorbed to a lesser extent than the rays passing through sound material. The images results in light and dark areas representing various density of material.
Radiographic examination is an important adjunct to the die-casting process, not only for indicating the internal condition of an aluminum die casting but also for determining the conditions to produce the best die casting. X-rays taken of die castings at the beginning or the breaking in of a new die can greatly aid the die caster in determining the effect of gate change, the extent of venting required, the effect of metal and die temperature and pressures, and other operating conditions. Such radiographs will show the results of each successive change in casting conditions and thus aid in arriving at the maximum soundness through a coordinated DOE.
Doehler, H.H. (1951) Die Casting. New York, New York. McGraw-Hill Book Company, Inc.