Rapid Ultrasonic Inspection of Artillery Projectiles.

Abstract : This report describes the results of an on-line, rapid ultrasonic inspection system for artillery projectiles using noncontact, electromagnetic acoustic transducers(EMATs). In Phase I, feasibility was demonstrated using the M-107 projectile as a medium. Based on these successful results, the present phase II was initiated with the purpose of adapting these results to the geometry of the M-549 (RAP) projectile. Included are discussions of the conceptual layout of a rapid, full automatic, microprocessor controlled inspection system based on the EMAT technology; the detailed design of the projectile handling system necessary to assure the reliable flow of projectiles through the system, including provisions for handling of rejected parts and consideration of compatibility with the production line of Norris Industries, in Vernon, California; the design and construction of an electromagnet to produce the magnetic bias necessary for optimum inspection; the design and construction of two ultrasonic channels; the demonstration of their ability to detect and locate EDM notches and naturally occurring defects in the M-549 projectile; and the possible effects of material variations such as surface decarburization. Based on the successful execution of these tasks, it is recommended that a complete prototype system be constructed and installed on a projectile production line in Phase III of this program.