: The resulting radiograph is visually compared against the ASTM E155 reference radiographs. The inspector identifies which severity level most closely matches the appearance of discontinuities in the casting.
The most authoritative source is ASTM International directly. Reference radiographs for E155 inspection (Volume I) are available as adjunct RRE015501, which includes 13 plates covering discontinuities in aluminum-alloy castings and 10 plates for magnesium-alloy castings. astm e155 porosity levels pdf repack