T9074-AS-GIB-010/271 Rev 1
7.3.3 Records. Records (see 1.8) of eddy current inspection shall contain the following: a. Description and unique identification of item inspected. b. Approved procedure identification. c. Instrument manufacturer, model number, and serial number. d. Probe description. e. Material type. f. Acceptance criteria used. g. Date of inspection. h. Signatures of inspectors. i. Disposition of the item inspected.
7.4 EQUIPMENT REQUIREMENTS.
7.4.1 Eddy Current Instrument. The instrumentation shall be capable of signal evaluation by both visual (meter readout) and audio sound pitch variations through connecting headphones, or by an impedance plane storage-type display. For all weld inspections, an impedance plane storage-type display instrument shall be used. The instrument shall provide a means for minimizing or adequately separating the effect of the lift off variable in the evaluation of test results. It shall be capable of detecting the notch in the performance verification reference block being used. 7.4.2 Performance Verification Reference Block. For non-ferromagnetic materials, a block of the same type of material that is to be inspected shall be used. For ferromagnetic materials, a block of material having similar electromagnetic properties (low alloy carbon steels such as HY, HTS, HSLA, etc. are considered similar) as that to be inspected shall be used. The block may be any convenient size provided that it does not present an edge-effect problem. The block shall contain a notch that is 0.015 inch deep, 0.250 inch long, and 0.010 inch wide (maximum dimensions). For the inspection of non- ferromagnetic welds, the reference block shall contain a weld and shall be of the same type of weld metal, same type of base metal and shall represent the same general surface condition (as welded, ground flush, etc.) as the weld being inspected with notches located as follows: one longitudinal notch in the weld metal, one longitudinal notch in the weld toe, one longitudinal notch in the base metal a minimum of ½ inch from the weld toe and one transverse notch in the weld metal. 7.5 STANDARDIZATION. Prior to inspection, verify the instrument performance using the performance verification reference block. This test shall produce a useable response from the notch(es) in the performance verification block and shall be discernible (in amplitude or phase) from material noise signals. The eddy current instrumentation shall then be normalized on an experimentally determined defect-free area of the item to be inspected. Standardization shall be accomplished at the following times: a. Immediately prior to starting an inspection. b. Whenever an inspection has been interrupted by the equipment being turned off or left unattended by the inspector. c. Whenever the inspector has reason to suspect that conditions affecting the standardization have changed. d. Not less than once every 4 hours. e. When the inspection has been completed. If a standardization check indicates the inspection sensitivity has decreased, all items tested since the last successful standardization shall be reinspected.
7.5.1 Painted/Coated Surfaces. Eddy current inspection shall not be performed through conductive coatings. Eddy current inspection may be performed through non-conductive coatings, but lift off affects due to the coating thicknesses shall
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