New and Refined Nondestructive Techniques for Graphite Billets and Shapes
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Report Number: AFML TR 70-212 Part 2
Author(s): Oaks, A. E.
Corporate Author(s): General Electric Company
Laboratory: Air Force Materials Laboratory
Date of Publication: 1971-07
Pages: 161
Contract: F33615-69-C-1623
DoD Project: 7351 - Metallic Materials
DoD Task:
Identifier: AD0736774
Abstract:
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.
Provenance: Lockheed Martin Missiles & Fire Control
Author(s): Oaks, A. E.
Corporate Author(s): General Electric Company
Laboratory: Air Force Materials Laboratory
Date of Publication: 1971-07
Pages: 161
Contract: F33615-69-C-1623
DoD Project: 7351 - Metallic Materials
DoD Task:
Identifier: AD0736774
Abstract:
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.
Provenance: Lockheed Martin Missiles & Fire Control