method for zerstoerungsfreien checking of lunkern in metallic gussstuecken on chemical composition

摘要

1,131,218. Activation analysis. HOESCH A. G. March 8, 1966 [March 29,1965], No.10145/66. Heading G1A. Metallic castings 13 leaving a rolling mill 11 are tested by first locating any cavities in the casting using a radiation method and then deter - mining the chemical composition of the cavity by activation analysis. The cavities are located by a known method using a Co 60 source of gamma rays 16 and a detector 17. A D-T neuton generator is controlled by the output of detector 17 to irradiate the centre of the cavity and also a sound portion of casting and the induced radio-activity is measured by a Nal scintillation counter 21. If the radio-activity of the cavity is greater than that of the metal, then the cavity contains oxidic slag and a cutter 24 is operated to remove the cavity. Slag-free cavities are not removed as these will disappear with further rolling.