Feasibility study on application of synchrotron radiation CT imaging to alloy steel for non-destructive inspection of inclusions

Shimamura, Yoshinobu*; Matsushita, Shinya*; Fujii, Tomoyuki*; Togo, Keiichiro*; Akita, Koichi*; Shobu, Takahisa  ; Shiro, Ayumi*

In order to examine the feasibility of applying synchrotron radiation CT imaging to alloy steels for non-destructive inspection of inclusions for potential origins of internal fatigue damage in the very high cycle region, synchrotron radiation CT imaging was utilized for repeated non-destructive observation of Cr-Mo steel. An ultrasonic fatigue testing machine was used in aid of the repeated observation. As a result, it was found that the synchrotron radiation CT imaging with 70 keV was useful for non-destructive observation of inclusions of more than 10 m, one of which may be an internal fatigue origin. No identifiable damage was observed around every inclusion, and in the base metal, at least up to 70% of fatigue life was observed in the imaging volume.