T9074-AS-GIB-010/271 Rev 1
CHAPTER 7 EDDY CURRENT TESTING
7.1 INTENDED USE. The inspection process covered is for the detection of surface cracks of ferromagnetic and nonferromagnetic materials. This method may only be used when authorized by the fabrication document, military specification, or other NAVSEA approval. 7.2 DEFINITIONS. The standard terminology for electromagnetic testing as described in ASTM E1316 shall apply to this section, except as noted below. 7.2.1 Normalize/Normalization. Adjustment of the eddy current system to provide a balanced response in an experimentally determined defect free area.
7.3 EDDY CURRENT INSPECTION REQUIREMENTS.
7.3.1 General Requirements.
7.3.1.1 Method. The overall inspection process shall consist of applying the eddy current test (ET) technique to detect surface cracks in the item inspected. 7.3.1.2 Surface Finish. The inspection surface for the ET scanning does not require removal of nonconductive coatings, for instance paint. The surface shall be reasonably smooth and clean. It shall be free of any substance that might inhibit free movement of the probe along the scan path. 7.3.2 Procedure. Eddy current inspection procedures shall contain, as a minimum, the following information. a. Material to be tested. b. Summary of process used. c. Equipment description. d. Performance verification description. e. Surface preparation. f. Normalization technique.
g. Scanning technique. h. Evaluation technique. i. Evaluation criteria. j. Recording and reporting requirements.
7-1
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