T9074-AS-GIB-010/271 Rev 1
can fall off the item before the inspection is complete, the magnetizing current shall remain on during the examination of the inspection area, and the evaluation of any detected indications. 4.4 EVALUATION OF INDICATIONS. When using either prods or yokes, any detected indications should be evaluated when maximized by moving the prods or yoke to the optimum magnetization position and re-applying the test. Prods should be placed parallel to the indication; yokes should be placed perpendicular to the indication. 4.5 DETERMINATION OF RELEVANCY. All indications revealed by magnetic particle inspection do not necessarily represent defects since non-relevant indications are sometimes encountered. All indications in weld craters shall be considered relevant. Indications caused by marking methods such as scribe lines and vibro-etching can be considered non-relevant unless the inspector has reason to believe that the marking is masking a relevant indication. If any other indications are believed to be non-relevant, the following methods may be used to prove non-relevancy: a. Not less than 10 percent of each type of indication shall be explored by removing the surface roughness believed to have caused the type of indication to determine if defects are present. The absence of indications under reinspection by magnetic particle inspection after removal of the surface roughness shall be considered to prove that the indications were non-relevant with respect to actual defects. If reinspection reveals any indications, these and all of the original indications shall be considered relevant. b. A liquid penetrant inspection after grinding to remove the surface roughness believed to have caused the indication. c. Other methods for determining non-relevancy shall be approved by the authorized representative of NAVSEA. d. For in-service inspection of lifting and handling equipment, 5X magnification may be used to determine the relevancy of indications believed to be caused by tool marks (tool chatter, die marks, etc.) nicks, scratches, gouges, or handling marks. The bottom of the depression shall be visible, rounded, and free of notches to be considered non- relevant. Every indication of this type shall be examined at 5X magnification when determining non-relevancy. If the disposition of the indication under evaluation is in question, the indication shall be evaluated as relevant. 4.6 FINAL CLEANING. After completion of inspection, all magnetic particles shall be removed from all parts. All temporary plugs shall be removed from holes and cavities. 4.7 ARC STRIKES. For applications governed by a fabrication document, arc strikes shall be removed and reinspected as required in the fabrication document. For other applications the following shall apply: All evidence of arc strikes shall be completely removed by mechanical means and faired into surrounding material, and reinspected using the prod or yoke method or visually inspected at not less than 5X magnification. Excavations and remaining wall thickness shall be inspected for and shall meet the requirements of the governing specification. 4.7.1 Arc Strikes in High Hardenability Materials. For all arc strikes that occur after final heat treatment in S-1 materials with carbon content greater than 0.30 percent, S-3, S-3A, S-4, S-5, S-6, and S-6A materials (as defined in S9074-AR-GIB-010/278), complete removal of the heat affected zone shall be verified with an etchant that has been demonstrated to disclose heat affected zone structure in the material involved unless repair welding is required. Etchants shall be prepared and used in accordance with good metallurgical practice.
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