Abstract
Utility of electron -diffraction reflection method has been shown by the present authors, for identification of the nonmetallic inclusions constituting sand-marks in steels. However, when the nonmetallic inclusions are large enough to charge the electron on them, their electron diffraction patterns cannot be obtained because of irregular scattering of the diffracted electron beam. This phenomenon is usually observed in the electron-diffraction of a poor electric conductive material.
To overcome this weak point of the electron-diffraction, it is adequate to apply the lowvelocity electron bombardment on the specimen in operating the electron-diffraction. In the present work, it was recognized that good results were obtained by the electron-diffraction reflection method using the supplementary low-velocity electron gun to identify the macroscopic nonmetallic inclusions constituting sand-marks in steel, and the usefulness of this method were shown.
