For the interpretation of radiographs and the assignment of radiographic quality levels to a casting, it is necessary to use a standard set of reference radiographs. The reference radiographs available from ASTM (see clause 2) are the only internationally used and recognized documents that may be used for this purpose.

• Year of Declaration: 1996
• Reference: ISO 4993: 1987
• Number of Pages: 2
• Code: GYS 159
• Version:
• ICS Number: 77.040.20