New and Refined Nondestructive Techniques for Graphite Billets and Shapes.
Summary rept. no. 2 (Final),
GENERAL ELECTRIC CO PHILADELPHIA PA RE-ENTRY AND ENVIRONMENTAL SYSTEMS DIV
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The limits of utility of several advanced NDT approaches for detecting small flaws in graphite were evaluated. Of these, focal plane ultrasonic inspection was found to be the most successful in delineating defects in depths of from 0.060 to 4 in. down to 0.020 to 0.030 in. diameter in ATJ-S and 0.010-in. diameter in AXF-90 graphite. For nearer surface inspection 1 MHz differential eddy current techniques can be applied to detect voids down to approximately 0.010 x 0.010 in. For billet and part inspection slit radiographic techniques were found to reduce scatter and parallax distortion induced image degradation and to achieve 10 to 15 percent improvements in the film contrast and defect resolution achieved with graphite. Author
- Ceramics, Refractories and Glass